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From: chidsey@smoke.BRL.MIL (Irving Chidsey)
Newsgroups: sci.bio,sci.med,sci.med.physics,sci.misc,sci.research
Subject: Re: Human Genetics
Message-ID: <12532@smoke.BRL.MIL>
Date: 6 Apr 90 14:39:22 GMT
References: <1138@wsu-cs>
Reply-To: chidsey@brl.arpa (Irving Chidsey (INF) <chidsey>)
Followup-To: sci.bio
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 36

In article <1138@wsu-cs> kkc@pandora.cs.wayne.edu (Kwok K. Chan) writes:
<
<This is a post for my friend who does not have access to USENET
<
<I am trying to write a paper related to human genetics and want to
<find out some more information of the following questions:
<
<1. I have heard when two close relatives get married, their children
<   will have a great chance of having defective genes. In other word,
<   it is very likely their children are mentally retarded, physically
<   deformed, etc.  Is there any medical journal, article, statistical
<   data or evidence that documented this type of issue? 
<
<2. What about two persons with same last name but are not relatives at
<   all.   Will they face the same risk?
<
<Thank you very much.
<
<Please reply to me via email :     kkc@cs.wayne.edu


	My understanding is that the risks are different.  Related people 
are more likely to share the same version (allele?) of a gene than unrelated
people.  Most defective genes are recessive, not dominant, so you have to
inherit two bad copies to get in trouble.  Unrelated people are less likely
to pass on the same defective genes so their offspring are less likely to
have problems.
	It is the enhanced possibility of getting two copies of the same
baddie that does you in.

							Irv
-- 
I do not have signature authority.  I am not authorized to sign anything.
I am not authorized to commit the BRL, the DOA, the DOD, or the US Government
to anything, not even by implication.
			Irving L. Chidsey  <chidsey@brl.mil>