Re: Can DNA test for heritage?

	Can you say "Put the lid back on that can, before all the
worms get out!"?   It has always been possible to sub-classify
humans and most other species by inheritable characteristics. Skin
color, shape of nose, shape of eyes, hair curls, and other
such visible characteristics are inherited.  The larger question
is "Why should we care or not care about inherited characteristics?"
The more we learn about genetics, the more we realize that what
makes us human is not in our genes but in our cultures.  Human DNA
in gene-coding regions is more than 99.5% identical to chimpanzee
DNA for the same genes.  In non-coding regions, human DNA is still 
more than 99% identical to chimpanzee DNA.  For almost all of our
genes and non-gene DNA, all humans are more than 99.995% identical,
it is a very small part of our 3 billion bases of DNA that accounts
for the rather large differences we see between individuals.
	In many parts of the world, people have focused on skin color
as an important genetic trait, but in some places where skin color
did not vary much, people focused on eye color or other traits to
seperate "us" from "them".  There is no genetic evidence that there
are any true "races" of people.  The ability to look at non-visible
characteristics such as blood type, HLA type, and non-coding DNA has
shown us that there is more variability within each ethnic group than
there is between ethic groups.  For example, all dark-skinned people
have blood types A, B, AB and o and all light-skinned people also
have blood types A, B, AB and o.
	The vast majority of differences between groups of people
are not genetic, but social.  Our customs, languages, habits, and
lifestyles evolve very much faster than our genes do.  In the 500,000
years or so that humans have been spreading out over the world, our
genes have changed very little, but our lifestyles and langauges
can evolve to be totally unrecognizable to one another in just
a fraction of that time.  The "romance languages" (French, Italian,
Spanish, Rumanian, Occitan, etc...) split from a common ancestral 
language (Roman or Latin) within the last 1500 years for example.
Here are some www pages that tell some of the history of this
small language group: http://www.orbilat.com/Proto-Romance/Proto-Romance.html http://www-student.unifr.ch/e-94/schmukim/pub/general/model.html http://cogprints.soton.ac.uk/view-hist-ling.html
	In the past 50,000 years humans have migrated all over
the world many times, spreading genes more rapidly than spreading
languages because most people adopt a new language when they
migrate into a new territory already inhabited by people.  Even
in cases where one culture over-rules another after conquering
them in war, the pre-existing language is often left in place, as
it is easier for the new rulers to learn the language than to
try to teach all the conquered people the ruler's language.
	So, if we sequenced hundreds of genes from all Native
American tribes from Alaska to the tip of Chile in South America,
we could eventually determine a few DNA base differences that were
most likley common among the people who travelled from Eastern
Siberia some 10,000 to 20,000 yars ago.  But there is also
good evidence that other smaller migrations have happened in
the time between that migration and the massive ship travel
started by Christopher Columbus and his peers.  Some Native
Americans will thus lack the specific DNA sites that we label
as "Native" because they picked up the European DNA when some
Viling or Celtic boat travelled to America 1,000 years ago.  Others
will have Siberian genes that migrated with people across the
Arctic ice over the past 2,000 years.  What would be the point of
telling a Navajo tribal leader that he or she is "not truly Navajo"
because he or she has a gene that migrated into their population
100 or 500 or 1,000 years ago?  
	Even with the skin coloration that so many people have focused
on, the focus has not been "fair" or rational.  A person who was 
1/4 African American and 3/4 European American is more often considered
to be "black" or African American.  A person who is 1/8 Native American
and who can trace that 1/8th ancestry to a particular tribe of 
Native Americans can often gain full rights to membership in the
tribe, and I believe that his or her children could then be considered
to be 100% "Native" if they married a tribal member.
	Human culture is inherited, but it is inherited in a Lamarkian
manner: we learn from our parents and peers.  While gene flow is 
completely horizontal and Darwinian, social evolution is not
constrained by the same rules that govern genetic evolution.  What
we are learning about genetics in the current boom of the "genetic
revolution" of molecular biology, should not be confused with what
we are learning about social evolution.  It is my personal opinion,
that if we could learn more about both types of evolution, it could
help stop some of the warfare that currently rages between various
ethnic groups of people.  We need to learn to look at our similarities
as closely as we look at our differences.