Re: What Are the Race Deniers Denying?

Philip Deitiker (pdeitik@bcm.tmc.edu)
Thu, 19 Dec 1996 20:56:18 GMT

<frank@clark.net> wrote:

>Maybe you can answer the obverse question: if there were "biologically
>meaningful" races in man, how would what we observe about human variation
>be different?

You _really_ don't want the answer to this question.

Here's how it would work. First one defines the variant populations of
the world, then one has a _l-o-n-g_ list of genotypes based on some
measurable phenotype (> 1000 loci). Then one place several columns (in
some cases a hundred columns) for each allele observed in all
populations. Then one goes down the list and places a allelic
frequency (percentage or proportion). At this point one a means of
comparing 2 different populations looking at the totality of
variation.

at some point the anaylsis might look like this

Population X
P allele
gene 1 2 3 4 5
aaa .97 .03 .001
aab .50 .33 .16 .05
aac 1
......
zzz

Population Y
same kind of thing

Let me give you some Idea of how close such a data set might be.
Suppose that one sets up 50 '"biologically meaningful" races' in
humans. From each population one wants to sample at least a thousand
individuals (for accuracies of 0.1%). That's 50,000 samples. Some
group of people needs to go out and collect those samples, and
collection in some groups is not going to be easy. After that, one
needs a basic genetic profile (human genome sequencing project). But
for this purpose, since one has to assume gene insertions and
deletions, the loci in question need to be sequenced from individuals
from diverse populations. Then one can proceed toward population
molecular analysis at the >1000 loci, some loci need analysis at
multiple positions because of multiple allelic variants, many may
need to have complete sequence. Estimated number of samples
150,000,000. Estimated time to completion >50 years.

What is achievable: The focus of modern medicine has been on alleles
with pathologies associated with them. This list is very long itself
but one really needs to identify the deviant allele(s) different
populations have different frequencies of 'disease' alleles and this
is of some relevence to the variant population problem.

The above definition of a population has alot more meaning when
describing a hybrid population, since the alleleic freqeuncies can be
predicted according to allelic frequencies in the parental population
multiplied by the proportion of each parental varient in the founding
population. 'Race' has a social constraint in this regard. I remind
you of plessy vs. ferguson and the social definition that anyone who
is 1/64 th black is consider black. In some areas a person of mixed
european/native american inheritance might be considered native
american (if they still belong to a particular tribe) or white if they
assimilate into the the 'white' population, irregardless of particular
genetic content. If we can go for a strict definition, that one is
white, black or asian if 50% or more of ones genes comes from
european, african, or asian anscestry this can help a little. The big
problem is that many folks cannot define to +/- 10% what their
'anscestry' is. Second problem is that northeast asians and amerinds
are likely a represetnative of some mixure of white and asian. Third
problem is middle easterners are likely mixtures of all three races
with frequencies varying greatly as one moves in one of the three
continental directions. Forth problem is the bioloical defintion of
the black race is _completely_ biologically meaningless. If one has a
mixture of white and black one presumbably has a mixture of white and
some regional african population (i.e. white/?black) two hybrids of
white/x and white/y are in fact two different hybrid populations and
pretty much can be attributed to european ignorance of african
regional populations. Some regions of the new world are
white/?black/amerind which really cannot be defined at all except via
genotypic analysis. Places like Spain, Italy, Greece are mixtures of
white?/black?. Biologically speaking race confuses the issue. These
mixtues themselves go back thousands of years and so the idea of
hybridization becomes a non-issue, each of these populations (and even
subpopulations) need to be individually defined.

Let me give and example of how complex the problem is.

We cannot know, with 100% certainty, when mixing events have occured;
however, from a historical and genetic point of view that they occured
(or are in the process) is certain. Thus inter-variant genetic
exchange can be represented at present as a set of processes in
varying states of completion. An example might be spain in which the
the last major immigration/emmigrations occured >500 ya. Thus spain
now has a gradient of peoples and if this population is isolated and
left alone eventually it will become more homogeneous (meaning less
regional variation). In the end, this population may not be
recognizabale as a hybrid. Other populations, such as many in asia
have all but completed, this process and now present themsleves as a
inseparable catagory. Others such as in the US still have a great deal
of polarity.

if one is to track how the process occurs (and qualifies race):

t(years) 100%x mixed% 100%y
0 50x 0 50y

100 45x 10 45y
300 20x 60 20y
1000 5 90z 5
3000 1 100z 1

in the beginning one has two recognizable groups x and y. Z is not
considered a group. In the end all (even x and y in z) are considered
z in z. Thus race x and race y disappear and at some arbitrary time
race z is attributed. If we look at z-3ky we find a sigmoidal
freqeuncy distribution of proportions of x and y contribution which
can be represented in the distribution of phenotypes. Problem is that
if one looks at any 'race' one sees the same distribution of
phenotypes. The argument about origin is that there was (at the time
of H.S. exodus from africa) 5 or more major groups of peoples that
have survived to modern times (all originally african). There several
processes that now form the current groups isolation, selection,
mixing. The human population has always been and is even so more now
in a constant state of dynamic equilibriums with regard to the
formation and disintegration (transformation) of populations. Some
populations (such as those in africa) are very stable. Others, such as
in eurasia are constantly changing. What we define as catagories today
will not be meaningful 300 years from now. OTOH, the populations we
define today can be associated with genetic population statistics
which allow for transformations.

Philip