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PROFESSOR: Did anybody have
any questions about this path

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00:00:25,070 --> 00:00:29,240
analysis where we ended
the class last time?

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00:00:29,240 --> 00:00:37,950
It's a way to find the
probability for two individuals

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when you know they're
related in some way.

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00:00:42,260 --> 00:00:50,830
But if you can draw
the family tree,

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00:00:50,830 --> 00:00:54,660
you're able to then,
using path analysis,

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00:00:54,660 --> 00:01:00,910
you can find the probability
that the two alleles at one

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locus are identical
or how many of them

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00:01:04,217 --> 00:01:05,300
are going to be identical.

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00:01:10,640 --> 00:01:13,590
It's called the
inbreeding coefficient

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00:01:13,590 --> 00:01:14,980
or the coefficient of kinship.

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00:01:18,370 --> 00:01:21,990
Both terms are used.

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00:01:21,990 --> 00:01:27,090
But you can use the same thing
to compute just how many genes

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do you get from your
great-grandparent, for example.

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00:01:31,900 --> 00:01:32,560
All right.

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00:01:39,390 --> 00:01:43,850
So this is the only slide
from the first class

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00:01:43,850 --> 00:01:45,380
I didn't get to.

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00:01:45,380 --> 00:01:49,904
We were talking about Wilson's
notes from E.O. Wilson's book.

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00:01:49,904 --> 00:01:51,390
I actually got these.

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00:01:51,390 --> 00:01:57,510
I read the abridged edition
for making those notes.

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00:01:57,510 --> 00:02:01,670
But he talks about
the possibility

29
00:02:01,670 --> 00:02:03,940
of inbreeding taboos.

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00:02:03,940 --> 00:02:07,410
When he introduces it,
he uses some more terms

31
00:02:07,410 --> 00:02:09,900
that are interesting.

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00:02:09,900 --> 00:02:15,130
He introduces by defining the
effective population number,

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00:02:15,130 --> 00:02:19,580
and I've defined it
at the bottom there.

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00:02:19,580 --> 00:02:21,830
The number of
individuals in an ideal

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00:02:21,830 --> 00:02:26,990
randomly breeding population
with 1-to-1 sex ratio

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00:02:26,990 --> 00:02:30,750
that would have the same rate
of heterozygosity decrease

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00:02:30,750 --> 00:02:34,740
as the total population
under consideration.

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00:02:34,740 --> 00:02:38,760
So that's what makes it
the effective population.

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00:02:41,810 --> 00:02:46,050
It's usually the smallest
number you can have and not

40
00:02:46,050 --> 00:02:47,320
have much inbreeding.

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00:02:50,387 --> 00:02:52,970
At least you would not have any
more inbreeding than you would

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00:02:52,970 --> 00:02:55,865
if they bred randomly in
the larger population.

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00:02:59,520 --> 00:03:02,010
And the numbers
aren't really big.

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00:03:02,010 --> 00:03:05,420
They get as low as 10 in
some animal-- some species,

45
00:03:05,420 --> 00:03:11,210
but they often are
more closer to 100.

46
00:03:11,210 --> 00:03:14,590
And then he talks about
Wright's island model.

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00:03:14,590 --> 00:03:21,610
Now what that is, he has a
model of a population that's

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00:03:21,610 --> 00:03:26,040
divided up into smaller groups.

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00:03:26,040 --> 00:03:32,310
And we know that it's probably,
at least very roughly,

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00:03:32,310 --> 00:03:34,690
many populations are
divided that way.

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00:03:34,690 --> 00:03:37,590
Certainly humans were throughout
much of our evolution.

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00:03:40,450 --> 00:03:43,100
That's why calls
it the island model

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00:03:43,100 --> 00:03:45,680
because he's got the
population divided

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00:03:45,680 --> 00:03:52,530
into these different groups
that he computed how big would

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00:03:52,530 --> 00:03:57,290
those groups have to be in order
to be this effective population

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00:03:57,290 --> 00:03:59,790
number definition.

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00:03:59,790 --> 00:04:03,580
And then what are the
advantages of a population being

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00:04:03,580 --> 00:04:06,120
divided that way?

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00:04:06,120 --> 00:04:07,780
And there are very
clear advantages

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00:04:07,780 --> 00:04:12,840
because when you
have smaller groups,

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00:04:12,840 --> 00:04:16,579
the genetic differences that
appear in the different groups

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00:04:16,579 --> 00:04:18,730
will differ.

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00:04:18,730 --> 00:04:23,070
And so you will have small
genetic differences appearing

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00:04:23,070 --> 00:04:26,030
in these different
groups, and they'll

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00:04:26,030 --> 00:04:28,500
be maintained if they're
not interbreeding.

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00:04:28,500 --> 00:04:34,660
Of course, they would
share the genes-- assumes

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00:04:34,660 --> 00:04:38,290
mating involved movement
from one group to the other.

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But if they're truly isolated,
that wouldn't be happening.

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What would be advantage to that?

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00:04:45,190 --> 00:04:47,800
What would be the advantage
if a population were

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divided that way?

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Well, think if there were some
big change in the environment

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00:04:54,530 --> 00:04:59,480
or new predators appeared
affecting all the groups.

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00:04:59,480 --> 00:05:02,080
Well, if there's genetic
differences in the groups,

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00:05:02,080 --> 00:05:04,480
then you're going to get
better survival in some groups

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00:05:04,480 --> 00:05:07,230
than in others.

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00:05:07,230 --> 00:05:15,490
And that's what Wright-- what
his model was able to show,

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00:05:15,490 --> 00:05:18,625
and that's one of the
consequences of that model.

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00:05:23,390 --> 00:05:25,740
And then he points
out these what

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00:05:25,740 --> 00:05:28,210
he calls supposed
selection tendencies that

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00:05:28,210 --> 00:05:32,540
affects sociality, two
very different effects

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00:05:32,540 --> 00:05:36,950
in small groups, that you have
a greater chance of inbreeding,

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and inbreeding generally
lowers individual fitness,

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00:05:42,950 --> 00:05:47,110
depresses performance,
lowers genetic adaptability.

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00:05:47,110 --> 00:05:51,510
So that is more likely
to happen, especially

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00:05:51,510 --> 00:05:54,240
if you're well below that
effective population number.

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00:05:57,610 --> 00:06:00,200
But in the small groups
of related individuals,

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00:06:00,200 --> 00:06:02,880
there would be very
clear advantages because

89
00:06:02,880 --> 00:06:05,100
of greater amounts of
altruistic behavior

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00:06:05,100 --> 00:06:07,850
and close cooperation
in the groups.

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00:06:11,520 --> 00:06:14,750
And then he talks about a
somewhat different concept,

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00:06:14,750 --> 00:06:18,770
assortative mating,
also known as homogamy.

93
00:06:18,770 --> 00:06:23,370
And this is the tendency you
find in all animal groups

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00:06:23,370 --> 00:06:25,110
and certainly in
humans, a tendency

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00:06:25,110 --> 00:06:27,439
to choose a mate that
looks similar to oneself

96
00:06:27,439 --> 00:06:28,480
or one's close relatives.

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00:06:32,980 --> 00:06:35,810
And what does that mean?

98
00:06:35,810 --> 00:06:42,210
Well, it probably means
that the group-- I

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00:06:42,210 --> 00:06:45,050
was talking to the
TAs about my worries

100
00:06:45,050 --> 00:06:48,280
that the second projector
will go out too.

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00:06:48,280 --> 00:06:50,800
There's a small chance
it's in the connection,

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00:06:50,800 --> 00:06:56,600
but I don't-- so far, so good.

103
00:07:04,740 --> 00:07:06,810
If you're going to
always choose a mate,

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00:07:06,810 --> 00:07:09,230
someone that looks similar
to yourself, then the chances

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00:07:09,230 --> 00:07:12,720
that you share genes, of
course, might be greater.

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00:07:12,720 --> 00:07:15,740
But that's only in a
relatively small number

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00:07:15,740 --> 00:07:20,180
of genes that affect the
superficial appearance.

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00:07:20,180 --> 00:07:20,680
All right.

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00:07:23,690 --> 00:07:33,620
That was the end of
that class, and then I

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00:07:33,620 --> 00:07:36,860
asked you to read
the chapter on genes,

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00:07:36,860 --> 00:07:39,010
genetic influences
on social behavior.

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00:07:42,160 --> 00:07:46,700
We want to know the difference
between genetic determinants

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00:07:46,700 --> 00:07:51,070
of behavioral traits, genetic
determination, and what

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00:07:51,070 --> 00:07:56,250
sociobiologists-- what
their view concerning

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00:07:56,250 --> 00:07:58,060
genes and behavior is.

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00:07:58,060 --> 00:08:00,770
because you know that
they've been accused

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00:08:00,770 --> 00:08:07,580
a lot of basically
saying genes are us.

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00:08:07,580 --> 00:08:10,880
Major trends are genetic.

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00:08:10,880 --> 00:08:13,140
Do the genes determine
the development

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00:08:13,140 --> 00:08:15,770
of specific social behaviors?

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00:08:15,770 --> 00:08:17,570
First of all, I want
you to think back

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00:08:17,570 --> 00:08:19,620
to our discussion of ethology.

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00:08:19,620 --> 00:08:22,430
And we talked about Konrad
Lorenz and fixed action

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00:08:22,430 --> 00:08:26,970
patterns, because
ethology was founded

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00:08:26,970 --> 00:08:31,750
on the basis of the heritability
of fixed action patterns.

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00:08:31,750 --> 00:08:34,210
And many of them are, of
course, social behavior.

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00:08:39,179 --> 00:08:43,870
But we also knew that a
fixed action pattern's not

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00:08:43,870 --> 00:08:47,300
totally determined by the genes.

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00:08:47,300 --> 00:08:51,080
It depends on
motivational levels,

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00:08:51,080 --> 00:08:53,260
and the motivational
intensity's influenced

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00:08:53,260 --> 00:08:56,670
by many environmental variables.

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00:08:56,670 --> 00:08:58,250
But the underlying
action pattern,

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00:08:58,250 --> 00:09:01,030
especially on the motor side,
the fixed motor pattern,

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00:09:01,030 --> 00:09:03,430
is considered
genetic, and there's

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00:09:03,430 --> 00:09:06,340
plenty of evidence for that.

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00:09:06,340 --> 00:09:09,500
You can even get
mouse populations

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00:09:09,500 --> 00:09:13,700
that are genetically different
that show differences

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00:09:13,700 --> 00:09:17,470
in details of grooming behavior.

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00:09:17,470 --> 00:09:23,020
And all the members that
have one genetic variant

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00:09:23,020 --> 00:09:25,680
will show one type, and
all of the individuals

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00:09:25,680 --> 00:09:28,680
are almost identical,
and the other groups

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00:09:28,680 --> 00:09:30,310
are a little bit different.

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00:09:30,310 --> 00:09:33,200
Certainly pretty strong
evidence for genetic influences

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00:09:33,200 --> 00:09:34,870
on that behavior.

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00:09:34,870 --> 00:09:37,440
That is only social
behavior, of course,

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00:09:37,440 --> 00:09:42,490
if there's grooming of
each other but in a group.

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00:09:45,190 --> 00:09:47,940
But I want you next
to remember that

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00:09:47,940 --> 00:09:55,990
the nature-nurture problem,
the way that controversy

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00:09:55,990 --> 00:10:00,070
is normally dealt with now,
especially in sociobiology,

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00:10:00,070 --> 00:10:08,700
is to remember that--
where are we here--

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00:10:08,700 --> 00:10:12,390
that both nature and
nurture are always involved.

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00:10:12,390 --> 00:10:15,386
You never have a purely
genetic determination.

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00:10:21,060 --> 00:10:23,800
And the other thing that
Alcock points out here

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00:10:23,800 --> 00:10:26,935
is that the genetic
studies most relevant to

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00:10:26,935 --> 00:10:31,220
sociobiology are not
developmental genetics

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00:10:31,220 --> 00:10:32,910
at all but population genetics.

157
00:10:35,680 --> 00:10:39,710
They deal most directly with
the consequences of population

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00:10:39,710 --> 00:10:43,020
changes and the frequency of
different variants or alleles

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00:10:43,020 --> 00:10:47,930
of given genes, not with the
means by which these alleles

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00:10:47,930 --> 00:10:51,890
shape or influence the pathways,
the biochemical pathways,

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00:10:51,890 --> 00:10:54,270
of developing individuals.

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00:10:54,270 --> 00:10:58,970
And so a lot of times, the
criticisms that sociobiologists

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00:10:58,970 --> 00:11:01,880
are genetic determinists
about social behavior

164
00:11:01,880 --> 00:11:03,680
is because they
don't distinguish

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00:11:03,680 --> 00:11:06,155
between ultimate and
proximate research in biology.

166
00:11:08,930 --> 00:11:21,060
And he considers that the main
problem with these criticisms,

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00:11:21,060 --> 00:11:25,720
especially the critics that
argue in this extreme passion,

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00:11:25,720 --> 00:11:29,520
they say that sociobiologists
are talking about traits that

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00:11:29,520 --> 00:11:32,800
are hereditary, fixed,
inevitable, unchangeable,

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00:11:32,800 --> 00:11:36,190
except by future selection
for hereditary alternatives.

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00:11:36,190 --> 00:11:40,530
Well, we know that
that can't be true

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00:11:40,530 --> 00:11:46,760
because of the nature
of what we know

173
00:11:46,760 --> 00:11:48,540
about how genes
influence behavior.

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00:11:53,950 --> 00:11:56,590
But let me ask you
about-- just leaving

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00:11:56,590 --> 00:12:00,900
these slides for a minute-- what
about these studies of ethology

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00:12:00,900 --> 00:12:06,660
where they're dealing with
like the cat mating behavior,

177
00:12:06,660 --> 00:12:08,710
for example?

178
00:12:08,710 --> 00:12:12,210
And you can find
relationships across species,

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00:12:12,210 --> 00:12:14,970
and the behavior is almost
identical in different groups.

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00:12:14,970 --> 00:12:16,220
Is that not social behavior?

181
00:12:16,220 --> 00:12:19,200
And isn't it
genetically determined?

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00:12:19,200 --> 00:12:23,052
And I would argue
that it certainly is,

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00:12:23,052 --> 00:12:26,281
but there are many
learned aspects as well.

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00:12:26,281 --> 00:12:26,780
OK?

185
00:12:26,780 --> 00:12:29,720
So you will find individual
differences in a group,

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00:12:29,720 --> 00:12:33,250
especially on the stimulus side.

187
00:12:33,250 --> 00:12:34,670
They develop
different preferences

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00:12:34,670 --> 00:12:38,145
and so forth, even when the
motor side is fairly fixed.

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00:12:43,550 --> 00:12:47,670
Then Alcock talks about
this review done in 1998--

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00:12:47,670 --> 00:12:50,000
so that was a long time
after the books appeared

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00:12:50,000 --> 00:13:00,840
in 1975-- about the study.

192
00:13:00,840 --> 00:13:03,260
He called it the "study
of genetically determined

193
00:13:03,260 --> 00:13:04,030
social behavior."

194
00:13:04,030 --> 00:13:08,170
That was the main
theme of the review.

195
00:13:08,170 --> 00:13:11,230
But Wilson actually
devotes an entire chapter

196
00:13:11,230 --> 00:13:13,720
in his book to explain
that although genes

197
00:13:13,720 --> 00:13:15,830
are essential for the
development of behavior,

198
00:13:15,830 --> 00:13:19,420
they don't determine
it by themselves.

199
00:13:19,420 --> 00:13:22,950
And of course, I
think most people

200
00:13:22,950 --> 00:13:24,555
who look at genes
and behavior now

201
00:13:24,555 --> 00:13:26,610
would say that that
would have to be true.

202
00:13:29,440 --> 00:13:32,890
You can go to an extreme like
Richard Alexander did here.

203
00:13:32,890 --> 00:13:39,220
He just points out that
genetic determinism

204
00:13:39,220 --> 00:13:43,350
is a ridiculous argument if you
exclude environment completely,

205
00:13:43,350 --> 00:13:46,250
environment outside the DNA,
because it's always there

206
00:13:46,250 --> 00:13:49,240
and there's always variables.

207
00:13:49,240 --> 00:13:50,620
Which, of course,
makes us wonder

208
00:13:50,620 --> 00:13:53,620
why the claim has
been so persistent.

209
00:13:53,620 --> 00:13:57,060
So I'll deal with that next.

210
00:13:57,060 --> 00:14:01,440
But this is the way Alcock
summarizes it, basically

211
00:14:01,440 --> 00:14:04,020
about at least the
chemical environment,

212
00:14:04,020 --> 00:14:09,030
the DNA is always involved
and that is [INAUDIBLE].

213
00:14:09,030 --> 00:14:11,580
But I want to point out
that a lot of people

214
00:14:11,580 --> 00:14:14,290
who argue against the
influence of genes,

215
00:14:14,290 --> 00:14:18,550
they're much more
concerned-- they just

216
00:14:18,550 --> 00:14:20,290
feel that environment
and learning are

217
00:14:20,290 --> 00:14:24,110
a lot more important,
OK, that you can discount

218
00:14:24,110 --> 00:14:26,650
a lot of the genetic factors.

219
00:14:26,650 --> 00:14:29,360
They also get upset by
thinking about behavior

220
00:14:29,360 --> 00:14:31,760
in a totally deterministic way.

221
00:14:31,760 --> 00:14:34,140
They basically object
to the basic assumption

222
00:14:34,140 --> 00:14:38,340
of the scientist who's
trying to explain

223
00:14:38,340 --> 00:14:41,850
physical causes of the
effects of whatever they're

224
00:14:41,850 --> 00:14:44,970
investigating, whether it's
behavior or anything else.

225
00:14:44,970 --> 00:14:47,780
I mean, psychologists
can't do their work

226
00:14:47,780 --> 00:14:53,820
without assuming that there are
specific effects on behavior

227
00:14:53,820 --> 00:14:56,740
including genetic effects.

228
00:14:56,740 --> 00:14:59,300
And so there are
people like that.

229
00:14:59,300 --> 00:15:02,630
They don't like, in general,
the deterministic approach

230
00:15:02,630 --> 00:15:04,050
that scientists take.

231
00:15:04,050 --> 00:15:08,450
So a lot of times, the
criticisms of those people

232
00:15:08,450 --> 00:15:11,350
is much broader than just
talking about sociobiology.

233
00:15:11,350 --> 00:15:14,749
But sociobiology is
what triggers their ire

234
00:15:14,749 --> 00:15:15,540
more than anything.

235
00:15:22,010 --> 00:15:27,160
So this is an enduring
myth, according to Alcock,

236
00:15:27,160 --> 00:15:29,300
despite the fact
that all biologists

237
00:15:29,300 --> 00:15:31,630
know that every trait
of every organism

238
00:15:31,630 --> 00:15:34,140
develops through the
[INAUDIBLE] interaction of genes

239
00:15:34,140 --> 00:15:35,600
and environment.

240
00:15:35,600 --> 00:15:38,560
But I think the myth persists.

241
00:15:38,560 --> 00:15:42,070
They don't like this approach,
as I just pointed out,

242
00:15:42,070 --> 00:15:43,690
for much more
general reasons that

243
00:15:43,690 --> 00:15:45,520
have to do just
with sociobiology.

244
00:15:45,520 --> 00:15:49,040
So this is a convenient straw
man to set it up like that.

245
00:15:49,040 --> 00:15:52,140
I think it's the nature
of human psychology.

246
00:15:52,140 --> 00:15:54,630
We believe in our
ability to change

247
00:15:54,630 --> 00:15:56,570
our behavior and other
people's behavior.

248
00:16:00,161 --> 00:16:04,100
And for many people, the
flexibility of human behavior

249
00:16:04,100 --> 00:16:08,430
is mistakenly taken as evidence
that cultural factors are

250
00:16:08,430 --> 00:16:10,650
the only real determinants
of our actions.

251
00:16:10,650 --> 00:16:13,950
In fact, in some of the meetings
where these arguments have come

252
00:16:13,950 --> 00:16:20,200
up, people usually outside
of sociobiology, of course,

253
00:16:20,200 --> 00:16:24,000
or behavioral biology
will argue that culture

254
00:16:24,000 --> 00:16:26,885
is the only real determinant
of human behavior.

255
00:16:29,700 --> 00:16:33,460
And again, I also feel
that championing free will

256
00:16:33,460 --> 00:16:38,940
and freedom of action is, pretty
understandably, very popular.

257
00:16:38,940 --> 00:16:42,600
In fact, I think
humans have evolved

258
00:16:42,600 --> 00:16:44,980
an enthusiasm for
freedom of action

259
00:16:44,980 --> 00:16:46,910
and a belief in free will.

260
00:16:46,910 --> 00:16:49,380
So I think we should be
thinking like sociobiologists

261
00:16:49,380 --> 00:16:50,600
about that.

262
00:16:50,600 --> 00:16:54,270
Why does everybody feel that?

263
00:16:54,270 --> 00:16:57,040
I mean, yes, there are some
intellectuals that take a very

264
00:16:57,040 --> 00:17:00,870
deterministic approach and say,
we think we have free will,

265
00:17:00,870 --> 00:17:01,570
but we don't.

266
00:17:01,570 --> 00:17:04,720
And they're being philosophical,
but in their own behavior,

267
00:17:04,720 --> 00:17:06,560
do they believe in free will?

268
00:17:06,560 --> 00:17:07,910
You bet.

269
00:17:07,910 --> 00:17:09,030
We all do.

270
00:17:09,030 --> 00:17:10,690
I think it's
inherited, and I think

271
00:17:10,690 --> 00:17:12,500
it's adapted to be that way.

272
00:17:15,849 --> 00:17:18,930
All right.

273
00:17:18,930 --> 00:17:24,050
Can a difference in one
allele change a behavior?

274
00:17:24,050 --> 00:17:25,580
And he has this
interesting figure

275
00:17:25,580 --> 00:17:30,290
3.1 to explain how
a difference in one

276
00:17:30,290 --> 00:17:33,110
allele-- and he has them
represented by the capital

277
00:17:33,110 --> 00:17:36,640
and the small b-- could result
in a behavioral difference

278
00:17:36,640 --> 00:17:38,240
between two adults.

279
00:17:38,240 --> 00:17:40,110
And it's a kind of
multiplier effect.

280
00:17:40,110 --> 00:17:41,850
This is the way
I've reproduced it.

281
00:17:48,200 --> 00:17:51,755
So you start with
the fertilized egg.

282
00:17:51,755 --> 00:17:52,255
OK?

283
00:17:52,255 --> 00:17:53,845
And here's one individual.

284
00:17:56,570 --> 00:17:59,950
Most of the genes are the
same except this gene here,

285
00:17:59,950 --> 00:18:05,890
and this could be
big B little b.

286
00:18:05,890 --> 00:18:07,840
But it's different from
this individual who

287
00:18:07,840 --> 00:18:10,890
has the two recessive
genes at the same locus.

288
00:18:10,890 --> 00:18:13,010
So his behavior, if it's
going to be affected,

289
00:18:13,010 --> 00:18:17,700
will be any effect
of that one allele.

290
00:18:17,700 --> 00:18:21,070
And this person doesn't
even have that allele,

291
00:18:21,070 --> 00:18:23,410
so he's got to be
affected by the other one.

292
00:18:23,410 --> 00:18:24,270
OK.

293
00:18:24,270 --> 00:18:29,900
It's just one gene,
so one protein.

294
00:18:29,900 --> 00:18:33,010
And that genetic
difference, of course,

295
00:18:33,010 --> 00:18:34,564
will interact with
the environment,

296
00:18:34,564 --> 00:18:36,105
and the environment
can be different.

297
00:18:38,720 --> 00:18:40,310
So the effects, if
the environment's

298
00:18:40,310 --> 00:18:42,160
different for these
two individuals,

299
00:18:42,160 --> 00:18:45,610
you're going to get differences
that affects the adult.

300
00:18:45,610 --> 00:18:50,050
But then as they develop, of
course, and neurons develop,

301
00:18:50,050 --> 00:18:53,370
we know that there are
many effects of environment

302
00:18:53,370 --> 00:18:56,790
on that that are
independent of these.

303
00:18:56,790 --> 00:19:00,780
But that, in fact, this
allele could make a difference

304
00:19:00,780 --> 00:19:03,050
in the way these things
happen during development.

305
00:19:03,050 --> 00:19:09,570
So the effect here could be
present throughout development

306
00:19:09,570 --> 00:19:11,820
[? within ?] environments,
as long as they're

307
00:19:11,820 --> 00:19:15,720
slightly different, could
lead to pretty big differences

308
00:19:15,720 --> 00:19:18,120
in two adults in
spite of that allele.

309
00:19:21,540 --> 00:19:24,690
And yet the differences
developed specifically

310
00:19:24,690 --> 00:19:26,530
because of that one
genetic difference.

311
00:19:26,530 --> 00:19:31,280
So that's all that we're
talking about here.

312
00:19:31,280 --> 00:19:35,340
So let's talk exactly how and
why the relative frequency

313
00:19:35,340 --> 00:19:38,810
of the two alleles could change
over multiple generations.

314
00:19:38,810 --> 00:19:42,550
Let's raise the possibilities
from what we know.

315
00:19:42,550 --> 00:19:43,260
OK?

316
00:19:43,260 --> 00:19:48,830
And these are the things I can
think of-- why B could increase

317
00:19:48,830 --> 00:19:54,070
and the recessive
trait could decrease.

318
00:19:54,070 --> 00:19:57,630
First of all, if b,
the recessive trait,

319
00:19:57,630 --> 00:20:00,280
resulted in death before
the age of reproduction

320
00:20:00,280 --> 00:20:04,544
more often than
the dominant trait.

321
00:20:04,544 --> 00:20:06,210
I'm just going to
refer to them that way

322
00:20:06,210 --> 00:20:11,210
because that's a common
way of expressing

323
00:20:11,210 --> 00:20:15,350
for one allele, the
recessive and dominant allele

324
00:20:15,350 --> 00:20:16,380
affecting that gene.

325
00:20:18,890 --> 00:20:21,840
The second thing,
it could result

326
00:20:21,840 --> 00:20:26,050
in behavioral difference,
reduce the probability

327
00:20:26,050 --> 00:20:28,720
of successful reproduction
in a particular environment

328
00:20:28,720 --> 00:20:30,210
but not in all environments.

329
00:20:30,210 --> 00:20:32,080
So at least in that
particular environment,

330
00:20:32,080 --> 00:20:35,360
the genes would change
in their frequency.

331
00:20:35,360 --> 00:20:39,010
All we need is
probability differences.

332
00:20:39,010 --> 00:20:42,270
And if the recessive trait
resulted in no change

333
00:20:42,270 --> 00:20:45,760
in probability of
reproduction, but it

334
00:20:45,760 --> 00:20:50,410
did reduce parental care,
that alone, you see,

335
00:20:50,410 --> 00:20:54,880
would result because you would
have, statistically anyway,

336
00:20:54,880 --> 00:20:58,460
less survival of the offspring.

337
00:20:58,460 --> 00:21:01,360
And that would be
enough then to lead

338
00:21:01,360 --> 00:21:03,490
to changes over
multiple generations

339
00:21:03,490 --> 00:21:05,080
in the frequency
of those two genes.

340
00:21:07,950 --> 00:21:10,120
All right.

341
00:21:10,120 --> 00:21:13,600
So let's talk about breeding
for behavioral traits.

342
00:21:13,600 --> 00:21:17,370
We know that animals are bred
for physical traits, how dogs

343
00:21:17,370 --> 00:21:19,340
have been bred to
look different.

344
00:21:19,340 --> 00:21:19,840
OK?

345
00:21:19,840 --> 00:21:25,250
And as we see it
especially in farm animals.

346
00:21:25,250 --> 00:21:29,610
We've bred beef cattle
so they're meatier.

347
00:21:29,610 --> 00:21:31,710
Well, what about behavior?

348
00:21:31,710 --> 00:21:34,350
It's been done in the
laboratory for a number

349
00:21:34,350 --> 00:21:37,200
of particular behavioral
traits, where you ignore

350
00:21:37,200 --> 00:21:42,030
any physical differences, and
you have a measure of behavior,

351
00:21:42,030 --> 00:21:45,420
for example, how
loud crickets sing.

352
00:21:45,420 --> 00:21:47,730
And the ones that
sing louder, you

353
00:21:47,730 --> 00:21:54,110
can breed those with each
other, the ones that sing less.

354
00:21:54,110 --> 00:21:56,694
And at the beginning,
they're probably all singing,

355
00:21:56,694 --> 00:21:58,610
but some of them don't
sing as loud as others.

356
00:21:58,610 --> 00:22:01,620
And if you keep breeding,
you will eventually

357
00:22:01,620 --> 00:22:05,640
end up with a loud singing
group and a pretty silent group.

358
00:22:05,640 --> 00:22:06,740
OK?

359
00:22:06,740 --> 00:22:08,700
It's also been done
with fruit flies.

360
00:22:08,700 --> 00:22:10,670
This has been the most common.

361
00:22:10,670 --> 00:22:13,610
And probably the most famous
experiments with fruit flies

362
00:22:13,610 --> 00:22:16,050
are the production of learning
mutants first produced

363
00:22:16,050 --> 00:22:18,380
by Chip Quinn of
this department.

364
00:22:18,380 --> 00:22:21,800
Most of that work he did
when he was at Princeton.

365
00:22:21,800 --> 00:22:26,520
And he produced
strains of fruit flies

366
00:22:26,520 --> 00:22:29,640
that, in a particular learning
test that he had set up

367
00:22:29,640 --> 00:22:34,690
to screen the fruit flies,
they were particularly stupid.

368
00:22:34,690 --> 00:22:36,550
And he named them
after vegetables.

369
00:22:36,550 --> 00:22:37,530
So he has rutabaga.

370
00:22:37,530 --> 00:22:41,930
He has turnip, and
such individuals.

371
00:22:41,930 --> 00:22:44,975
And he became well known
for that work, the learning

372
00:22:44,975 --> 00:22:47,610
mutants in fruit flies.

373
00:22:47,610 --> 00:22:54,470
It's also been done
in mice and in rats.

374
00:22:54,470 --> 00:22:58,120
In mice, they produced
spatial learning differences

375
00:22:58,120 --> 00:23:00,020
in different groups
and groups that

376
00:23:00,020 --> 00:23:02,330
differed in
nest-building activity.

377
00:23:02,330 --> 00:23:04,940
You just select
the ones that are

378
00:23:04,940 --> 00:23:08,050
most vigorous about
building big nests

379
00:23:08,050 --> 00:23:10,200
and the ones that don't
build such big nets

380
00:23:10,200 --> 00:23:12,490
and don't nest in
such a vigorous way.

381
00:23:12,490 --> 00:23:15,600
And if you breed
them selectively

382
00:23:15,600 --> 00:23:17,110
for those behavioral
traits, you'll

383
00:23:17,110 --> 00:23:21,023
eventually get groups that
are very, very different

384
00:23:21,023 --> 00:23:22,930
in the way they build nests.

385
00:23:22,930 --> 00:23:25,490
And you can do the same thing
for spatial learning problems.

386
00:23:25,490 --> 00:23:27,980
And there the best known
is the rat experiments,

387
00:23:27,980 --> 00:23:33,370
where they had what was
called the Hebb-Williams maze,

388
00:23:33,370 --> 00:23:37,107
a maze, a fairly complex maze,
that they could change easily.

389
00:23:37,107 --> 00:23:38,940
They can change the
problem so the rat would

390
00:23:38,940 --> 00:23:40,440
be trained on one,
and then they'd

391
00:23:40,440 --> 00:23:44,880
change the barriers around,
test them again, and do that

392
00:23:44,880 --> 00:23:45,500
repeatedly.

393
00:23:45,500 --> 00:23:48,280
And they'd come up with a
measure of how intelligent--

394
00:23:48,280 --> 00:23:50,920
it was called a rat
intelligence test--

395
00:23:50,920 --> 00:23:52,900
how smart are they
in learning mazes.

396
00:23:52,900 --> 00:23:56,110
And of course, some of them
learn much better than others.

397
00:23:56,110 --> 00:23:58,410
And so again, we can
selectively breed them

398
00:23:58,410 --> 00:24:00,930
for how well they
learn the maze.

399
00:24:00,930 --> 00:24:03,400
The ones that learn
better we'll interbreed

400
00:24:03,400 --> 00:24:06,430
with those ones that
learn more poorly.

401
00:24:06,430 --> 00:24:08,965
And you end up with a
maze-bright, maze-dull strain.

402
00:24:08,965 --> 00:24:12,490
And then you can test
for other differences

403
00:24:12,490 --> 00:24:15,679
and what else happens to
[? this animal? ?] What happens

404
00:24:15,679 --> 00:24:16,220
in the brain?

405
00:24:19,960 --> 00:24:23,070
It was the fruit fly work
that led most directly

406
00:24:23,070 --> 00:24:25,540
to neuroscience studies.

407
00:24:25,540 --> 00:24:28,070
In fact, Chip,
after he came here,

408
00:24:28,070 --> 00:24:33,190
eventually did zero in
on a particular gene

409
00:24:33,190 --> 00:24:37,170
for a particular
factor in the brain

410
00:24:37,170 --> 00:24:40,670
that was found by
other groups also

411
00:24:40,670 --> 00:24:43,250
to be involved in learning.

412
00:24:43,250 --> 00:24:46,020
OK.

413
00:24:46,020 --> 00:24:50,340
And when we deal with humans,
the best studies probably

414
00:24:50,340 --> 00:24:54,620
that support genetic
influences on behavior

415
00:24:54,620 --> 00:24:57,380
are the twin studies.

416
00:24:57,380 --> 00:25:04,110
Do you all know the experiments
studying concordance rates?

417
00:25:04,110 --> 00:25:06,140
First of all, you
have to collect

418
00:25:06,140 --> 00:25:13,430
large numbers of identical
twins so that you

419
00:25:13,430 --> 00:25:19,240
can either test them or
find out a lot about them.

420
00:25:19,240 --> 00:25:22,750
For example, do they
become schizophrenic?

421
00:25:22,750 --> 00:25:25,844
And so that's certainly a
big behavioral difference,

422
00:25:25,844 --> 00:25:28,010
the ones that become
schizophrenic and the ones that

423
00:25:28,010 --> 00:25:29,040
don't.

424
00:25:29,040 --> 00:25:35,590
So if one of the twins, you
find out, is schizophrenic,

425
00:25:35,590 --> 00:25:39,100
what is the probability that his
twin will have schizophrenia?

426
00:25:39,100 --> 00:25:42,850
Do you know what
the probability is?

427
00:25:42,850 --> 00:25:44,850
It's about 2/3.

428
00:25:44,850 --> 00:25:45,670
OK?

429
00:25:45,670 --> 00:25:48,780
So it's not totally genetic.

430
00:25:48,780 --> 00:25:53,600
And it's interesting that
that 2/3 for schizophrenia

431
00:25:53,600 --> 00:25:57,650
also applies to the
kind of diabetes I have.

432
00:25:57,650 --> 00:26:01,770
If I had a twin
brother-- OK, it would

433
00:26:01,770 --> 00:26:05,210
have to be a brother because
I'd have to be monozygotic

434
00:26:05,210 --> 00:26:09,160
OK-- the brother would
have a 2/3 chance of having

435
00:26:09,160 --> 00:26:11,080
the same thing.

436
00:26:11,080 --> 00:26:14,830
The concordance
rate is not 100%.

437
00:26:14,830 --> 00:26:19,040
So that just means there has to
be environmental factors that

438
00:26:19,040 --> 00:26:21,780
also have a strong influence.

439
00:26:21,780 --> 00:26:28,750
And the degree to which the
genetics and environment play

440
00:26:28,750 --> 00:26:33,790
roles can be estimated from just
studying concordance rates, OK,

441
00:26:33,790 --> 00:26:36,420
and that has been done for a
number of different things.

442
00:26:41,060 --> 00:26:45,350
About the selected reading
for behavioral traits,

443
00:26:45,350 --> 00:26:49,705
I like many of the examples in
this book by Temple Grandin.

444
00:26:49,705 --> 00:26:51,790
She's a very interesting lady.

445
00:26:51,790 --> 00:26:55,250
She's actually, I believe,
come here to give a talk once,

446
00:26:55,250 --> 00:26:56,820
at least I've heard her.

447
00:26:56,820 --> 00:27:00,650
I think when I
heard her, she was

448
00:27:00,650 --> 00:27:05,670
promoting one of her
books, probably this one,

449
00:27:05,670 --> 00:27:08,270
at the bookstore in Porter
Square where they get authors

450
00:27:08,270 --> 00:27:11,910
to come every week and sometimes
twice a week to give talks

451
00:27:11,910 --> 00:27:13,740
on their new books.

452
00:27:13,740 --> 00:27:17,430
And I met her.

453
00:27:17,430 --> 00:27:18,720
I had a copy of her book.

454
00:27:18,720 --> 00:27:22,070
She signed it and talked
to me about the teaching

455
00:27:22,070 --> 00:27:24,160
I was doing at MIT and so forth.

456
00:27:24,160 --> 00:27:25,685
Gave me permission,
carte blanche,

457
00:27:25,685 --> 00:27:28,520
to use anything in
her book in class.

458
00:27:28,520 --> 00:27:29,020
OK.

459
00:27:29,020 --> 00:27:34,450
So she points out various
things, behavioral traits,

460
00:27:34,450 --> 00:27:37,260
that dogs have been bred for.

461
00:27:37,260 --> 00:27:40,040
They've been bred, as you
know, for herding ability,

462
00:27:40,040 --> 00:27:43,520
for example, the sheep dog.

463
00:27:43,520 --> 00:27:46,230
If you want to herd
sheep, and you really

464
00:27:46,230 --> 00:27:49,790
do need dogs to
do it efficiently,

465
00:27:49,790 --> 00:27:52,860
you don't want to
choose just any dog,

466
00:27:52,860 --> 00:27:55,720
no matter how smarter
he is, how loyal.

467
00:27:55,720 --> 00:27:58,110
They are genetically different.

468
00:27:58,110 --> 00:28:01,160
And they have been bred
specifically for herding.

469
00:28:01,160 --> 00:28:06,060
So the sheep dog
is very, very good.

470
00:28:06,060 --> 00:28:09,950
You're enhancing certain
fixed action patterns

471
00:28:09,950 --> 00:28:14,040
and decreasing the influence
of other fixed action patterns.

472
00:28:14,040 --> 00:28:21,890
In a way, you're enhancing
detecting and stalking

473
00:28:21,890 --> 00:28:25,070
behavior, but you're
inhibiting the later parts

474
00:28:25,070 --> 00:28:27,910
of the predatory behavior.

475
00:28:27,910 --> 00:28:29,560
They never attack the sheep.

476
00:28:32,070 --> 00:28:35,300
I mean, this predatory
attack is also

477
00:28:35,300 --> 00:28:39,530
determined by multiple genes
or multiple components.

478
00:28:39,530 --> 00:28:41,790
It's not a single fixed
action pattern really,

479
00:28:41,790 --> 00:28:44,010
at least on the motor side.

480
00:28:44,010 --> 00:28:47,150
Then retrievers,
same kind of thing.

481
00:28:47,150 --> 00:28:49,150
Some dogs are
terrible retrievers.

482
00:28:49,150 --> 00:28:52,290
But if you get a golden
retriever or a Labrador

483
00:28:52,290 --> 00:28:58,040
retriever, very easy because
it's part of their genetics.

484
00:28:58,040 --> 00:29:02,170
And of course, they're
trained for hunting, pointing.

485
00:29:02,170 --> 00:29:05,140
I remember my father
who hunted pheasants.

486
00:29:05,140 --> 00:29:08,200
He had a pointer when
I was a little kid.

487
00:29:08,200 --> 00:29:14,490
And I still remember that dog
because he was so incredibly--

488
00:29:14,490 --> 00:29:19,770
not just so incredibly loyal to
my father and not to his kids,

489
00:29:19,770 --> 00:29:22,910
he was so good at what he did.

490
00:29:22,910 --> 00:29:26,840
He would stay right
at my father's side.

491
00:29:26,840 --> 00:29:30,270
I mean, they're used for
their incredibly good senses

492
00:29:30,270 --> 00:29:38,270
but also for their ability
to detect the pheasant,

493
00:29:38,270 --> 00:29:44,030
and then stop and withhold
their tendency to try

494
00:29:44,030 --> 00:29:46,990
to grab it and
attack it themselves.

495
00:29:46,990 --> 00:29:49,490
You know, pheasants are
mostly on the ground.

496
00:29:49,490 --> 00:29:52,890
They can fly to get away.

497
00:29:52,890 --> 00:29:55,845
So he would become rigid
and go into this posture.

498
00:29:55,845 --> 00:29:58,300
It was very obvious.

499
00:29:58,300 --> 00:30:02,900
And then a little signal
from my father, then the dog

500
00:30:02,900 --> 00:30:06,610
would rush forward,
not to try to kill

501
00:30:06,610 --> 00:30:10,470
the pheasant but to flush
him so he would fly up.

502
00:30:10,470 --> 00:30:13,700
Because people that hunt
like this usually wait.

503
00:30:13,700 --> 00:30:15,240
If they can't shoot
them in the air,

504
00:30:15,240 --> 00:30:17,090
they're not good
enough shots for that,

505
00:30:17,090 --> 00:30:22,290
then they don't succeed
in getting the pheasant.

506
00:30:22,290 --> 00:30:23,980
And I remember the
situation where

507
00:30:23,980 --> 00:30:26,300
there were two
pheasants pulled up,

508
00:30:26,300 --> 00:30:29,640
and my father had a
double-barreled shotgun.

509
00:30:29,640 --> 00:30:31,740
And he got both pheasants.

510
00:30:31,740 --> 00:30:34,410
And then another little
signal, out the dog

511
00:30:34,410 --> 00:30:36,590
went to retrieve them.

512
00:30:36,590 --> 00:30:38,180
So he could do both
of these things,

513
00:30:38,180 --> 00:30:42,700
retrieving, pointing, hunting.

514
00:30:42,700 --> 00:30:46,220
And yet many breeds of
animals, you cannot train them.

515
00:30:46,220 --> 00:30:48,930
In fact, they weren't
very good with children.

516
00:30:48,930 --> 00:30:53,460
So as his kids
started growing older,

517
00:30:53,460 --> 00:30:59,690
he gave the pointer to a
farmer who had a lot of space.

518
00:30:59,690 --> 00:31:02,981
We were now living in a town.

519
00:31:02,981 --> 00:31:05,480
When he did that hunting, we
were still outside of the town.

520
00:31:05,480 --> 00:31:09,120
But then he moved into the town
so his kids could go to school,

521
00:31:09,120 --> 00:31:16,550
and got a dachshund, a
much better family dog.

522
00:31:16,550 --> 00:31:18,100
OK.

523
00:31:18,100 --> 00:31:20,730
So that's the dog I became
most familiar with as I

524
00:31:20,730 --> 00:31:22,090
was growing up.

525
00:31:22,090 --> 00:31:25,870
Farm animals we know have been
bred very specifically not just

526
00:31:25,870 --> 00:31:29,730
for their physical
nature, but you

527
00:31:29,730 --> 00:31:33,620
can't help but when you're
breeding farm animals,

528
00:31:33,620 --> 00:31:38,180
you'll tend to choose the ones
that aren't as aggressive.

529
00:31:38,180 --> 00:31:42,475
So aggression has been reduced
in the cattle, for example.

530
00:31:45,360 --> 00:31:49,220
And the amount of meat they
produce has been increased.

531
00:31:49,220 --> 00:31:52,759
For chickens, of course,
it's egg-laying ability,

532
00:31:52,759 --> 00:31:53,800
and that's been enhanced.

533
00:31:56,960 --> 00:32:00,450
They also breed chickens,
of course, for meat.

534
00:32:00,450 --> 00:32:01,800
Bulls, it's a little different.

535
00:32:01,800 --> 00:32:04,940
And you find bulls
that are breeders

536
00:32:04,940 --> 00:32:08,700
at cattle farms in the US
where they breed cattle.

537
00:32:08,700 --> 00:32:10,600
Again, they choose
bulls that are-- they

538
00:32:10,600 --> 00:32:12,280
have to limit their aggression.

539
00:32:12,280 --> 00:32:16,024
But you want big, meaty
bulls because that's

540
00:32:16,024 --> 00:32:17,190
what you're trying to breed.

541
00:32:22,290 --> 00:32:24,850
My grandfather knew
all about this kind

542
00:32:24,850 --> 00:32:26,820
of breeding of the
bulls because I

543
00:32:26,820 --> 00:32:30,840
remember he wanted to
let us see how he did it.

544
00:32:30,840 --> 00:32:33,980
And he went in on
horseback and got a bull.

545
00:32:33,980 --> 00:32:35,480
And here comes the
bull, and we were

546
00:32:35,480 --> 00:32:37,090
all right there in the yard.

547
00:32:37,090 --> 00:32:40,200
Here comes this charging bull.

548
00:32:40,200 --> 00:32:43,280
You could imagine what we felt.

549
00:32:43,280 --> 00:32:45,270
Here's this is charging bull.

550
00:32:45,270 --> 00:32:48,750
But the bull, well
known to my grandfather,

551
00:32:48,750 --> 00:32:52,020
was not interested
in kids at all.

552
00:32:52,020 --> 00:32:54,060
He was only interested
in one thing,

553
00:32:54,060 --> 00:32:56,400
those females in the yard.

554
00:32:56,400 --> 00:33:00,480
So my cousin opened the
gate, the bull ran through,

555
00:33:00,480 --> 00:33:05,540
and immediately began soliciting
the attentions of the females.

556
00:33:05,540 --> 00:33:06,280
OK.

557
00:33:06,280 --> 00:33:08,980
But of course, if you're using
the bulls for other things,

558
00:33:08,980 --> 00:33:11,970
like bullfighting, then
you breed them differently.

559
00:33:11,970 --> 00:33:15,690
And there are bull
breeders in Spain

560
00:33:15,690 --> 00:33:20,500
that specifically breed
bulls for their ferocity

561
00:33:20,500 --> 00:33:23,100
in bullfighting.

562
00:33:23,100 --> 00:33:24,910
And we know, of
course, we're more

563
00:33:24,910 --> 00:33:26,720
familiar with the
breeding of horses.

564
00:33:26,720 --> 00:33:29,300
And they've been bred
for various things,

565
00:33:29,300 --> 00:33:34,885
for speed, the Thoroughbred,
for herding cattle.

566
00:33:37,400 --> 00:33:39,520
The quarter horse,
they're actually

567
00:33:39,520 --> 00:33:43,430
faster than the Thoroughbred
for a quarter of a mile,

568
00:33:43,430 --> 00:33:46,100
but they can't keep up with the
Thoroughbred in a longer race.

569
00:33:48,900 --> 00:33:51,760
And so there's several
breeds of horses.

570
00:33:51,760 --> 00:33:56,660
We know that workhorses tend to
be bigger, meatier, stronger,

571
00:33:56,660 --> 00:33:57,880
but slower.

572
00:33:57,880 --> 00:34:00,730
But they're used to pull
things, pull wagons,

573
00:34:00,730 --> 00:34:03,320
pull plows, and so forth.

574
00:34:03,320 --> 00:34:06,830
Few of them now, but some of
them are still maintained.

575
00:34:06,830 --> 00:34:11,120
So very specific breeding
for behavioral traits.

576
00:34:11,120 --> 00:34:14,480
So this question
concerns the problems

577
00:34:14,480 --> 00:34:16,670
that often happen
when animals are

578
00:34:16,670 --> 00:34:19,280
bred for a single
physical trait.

579
00:34:19,280 --> 00:34:22,100
What happens to them?

580
00:34:22,100 --> 00:34:24,710
It's common for behavioral
problems to appear.

581
00:34:24,710 --> 00:34:29,480
And this is discussed quite a
bit in Temple Grandin's book.

582
00:34:29,480 --> 00:34:32,530
Her example I liked
was Collie dogs,

583
00:34:32,530 --> 00:34:37,772
because when I was
growing up, I remember--

584
00:34:37,772 --> 00:34:39,320
do you remember Lassie?

585
00:34:39,320 --> 00:34:41,110
I don't know if you
even who Lassie is,

586
00:34:41,110 --> 00:34:44,051
but that was a popular
dog in Hollywood movies.

587
00:34:44,051 --> 00:34:53,699
And Lassie grew up before this
intense breeding in this period

588
00:34:53,699 --> 00:34:56,909
started to change the
appearance of Collies

589
00:34:56,909 --> 00:35:00,495
to make them have narrower
and narrower skulls

590
00:35:00,495 --> 00:35:04,090
and emphasize the needle nose.

591
00:35:04,090 --> 00:35:08,450
So she said the result
was "brainless ice picks,"

592
00:35:08,450 --> 00:35:12,390
not like Lassie at all.

593
00:35:12,390 --> 00:35:16,730
And that's the danger if
you just ignore behavior

594
00:35:16,730 --> 00:35:20,140
when you're breeding for a
particular physical trait.

595
00:35:20,140 --> 00:35:22,570
And this is not
the only example.

596
00:35:22,570 --> 00:35:25,910
Breeds of dogs have
particular problems.

597
00:35:25,910 --> 00:35:29,390
Usually it's that they
get certain diseases.

598
00:35:29,390 --> 00:35:31,290
Cocker Spaniels, for
example, many of them

599
00:35:31,290 --> 00:35:33,570
get a type of epilepsy.

600
00:35:33,570 --> 00:35:36,420
That's certainly a major
behavioral problem,

601
00:35:36,420 --> 00:35:39,050
behavioral disease,
that they get because

602
00:35:39,050 --> 00:35:40,660
of this breeding for
their appearance.

603
00:35:44,470 --> 00:35:48,400
So is it true that no genes for
human behavior have been found?

604
00:35:51,340 --> 00:35:53,530
The argument was
that we can dispense

605
00:35:53,530 --> 00:35:55,610
with the direct evidence
for a genetic basis

606
00:35:55,610 --> 00:35:58,410
of human social [? forms ?]
in a single word, no evidence.

607
00:36:00,950 --> 00:36:04,460
And here's another quote
from this book called

608
00:36:04,460 --> 00:36:09,650
Not in Our Genes by the Harvard
professor Lewontin, Rose,

609
00:36:09,650 --> 00:36:11,750
a British professor,
and Kamin, I

610
00:36:11,750 --> 00:36:14,606
don't remember where he's from.

611
00:36:14,606 --> 00:36:16,480
He said, "No one has
ever been able to relate

612
00:36:16,480 --> 00:36:20,010
any aspect of human social
behavior to any particular gene

613
00:36:20,010 --> 00:36:20,770
or set of genes."

614
00:36:20,770 --> 00:36:22,880
Is that true still?

615
00:36:22,880 --> 00:36:24,930
I don't think so.

616
00:36:24,930 --> 00:36:28,440
First of all, in your book
there, Alcock just points

617
00:36:28,440 --> 00:36:30,400
out the absence of
evidence isn't really

618
00:36:30,400 --> 00:36:33,060
evidence of absence
of non-involvement

619
00:36:33,060 --> 00:36:34,440
of genes in social development.

620
00:36:37,040 --> 00:36:39,320
I guess it seemed
to him that way,

621
00:36:39,320 --> 00:36:41,050
and that was the
argument he made.

622
00:36:41,050 --> 00:36:43,230
But I would point out
more recent evidence

623
00:36:43,230 --> 00:36:51,480
for specific genes we say
for a social behavior.

624
00:36:51,480 --> 00:36:53,320
I want you to keep
in mind that even

625
00:36:53,320 --> 00:36:55,660
though specific genes
[? aren't ?] being found that

626
00:36:55,660 --> 00:36:59,570
are correlated with various
social behaviors and especially

627
00:36:59,570 --> 00:37:05,340
behavioral problems, they're
not-- genes code for proteins,

628
00:37:05,340 --> 00:37:06,200
OK?

629
00:37:06,200 --> 00:37:09,640
And if you look at these
behaviors, these abnormalities

630
00:37:09,640 --> 00:37:11,570
in humans, autism,
schizophrenia,

631
00:37:11,570 --> 00:37:14,260
and other mental diseases,
attention deficit,

632
00:37:14,260 --> 00:37:15,970
hyperactivity
disorder, yes, there's

633
00:37:15,970 --> 00:37:18,340
genetic contribution
to all of these.

634
00:37:18,340 --> 00:37:20,860
There's always multiple
genes involved,

635
00:37:20,860 --> 00:37:24,671
and environmental
effects are still strong.

636
00:37:24,671 --> 00:37:25,170
OK?

637
00:37:27,770 --> 00:37:30,110
So how could a
gene that has what

638
00:37:30,110 --> 00:37:32,920
appears to be
maladaptive consequences

639
00:37:32,920 --> 00:37:35,460
be present in some
animals or people today?

640
00:37:35,460 --> 00:37:38,370
Why wasn't it lost?

641
00:37:38,370 --> 00:37:39,790
It's about the
first thing I asked

642
00:37:39,790 --> 00:37:43,150
when I got diabetes at age 24.

643
00:37:43,150 --> 00:37:45,520
What's this gene doing around?

644
00:37:45,520 --> 00:37:50,150
Should have disappeared
1,000 years ago.

645
00:37:50,150 --> 00:37:52,330
First of all, it could
be a recent mutation

646
00:37:52,330 --> 00:37:54,750
and will be lost.

647
00:37:54,750 --> 00:37:59,980
Or maybe it has its bad
effects after reproduction.

648
00:37:59,980 --> 00:38:08,760
I said I got it at age 24, so
during the age of reproduction.

649
00:38:08,760 --> 00:38:11,570
Many effects do occur later.

650
00:38:11,570 --> 00:38:14,125
It may have effects only
in certain environments.

651
00:38:14,125 --> 00:38:15,500
If I weren't in
an environment, I

652
00:38:15,500 --> 00:38:17,830
wasn't exposed to
the same viruses,

653
00:38:17,830 --> 00:38:19,360
I may never have gotten it.

654
00:38:19,360 --> 00:38:23,860
It's an autoimmune disease
triggered by viruses.

655
00:38:23,860 --> 00:38:26,380
It's also, of course, because
of modern medical treatments.

656
00:38:26,380 --> 00:38:29,320
But it's also-- remember
genetic swamping.

657
00:38:29,320 --> 00:38:32,170
If you've forgotten what
that is, go back and read it.

658
00:38:32,170 --> 00:38:36,570
It was in my notes, and you
can find it also on the web.

659
00:38:36,570 --> 00:38:39,880
And then I'm posting
these homework questions.

660
00:38:39,880 --> 00:38:43,960
It's already at the
end of the class here.

661
00:38:43,960 --> 00:38:48,110
I want you to spend most
of the time on this one.

662
00:38:48,110 --> 00:38:49,610
The others should
be easier for you.

663
00:38:49,610 --> 00:38:52,370
If you have trouble with those,
I'm happy to give you hints.

664
00:38:52,370 --> 00:38:53,802
I'm asking you to do these.

665
00:38:53,802 --> 00:38:56,260
They're similar to homework I
gave last year because I want

666
00:38:56,260 --> 00:38:57,843
you to think about
these things and be

667
00:38:57,843 --> 00:39:02,184
clear about the type of
thinking you need to do.

668
00:39:02,184 --> 00:39:03,850
And this is the one
that causes the most

669
00:39:03,850 --> 00:39:05,990
controversy, so
think about that.

670
00:39:05,990 --> 00:39:09,240
And you can ask me about
it on Friday, if you wish,

671
00:39:09,240 --> 00:39:12,130
and I'm happy to give
you some suggestions.