http://www.gnxp.com/new/2008/06/18/genetic-relatedness/ Genetics Tue, 03 Apr 2018 05:20:42 +0000 hourly 1 https://wordpress.org/?v=3.8.27 http://www.gnxp.com/new/2008/06/18/genetic-relatedness/#comment-21373 Thu, 19 Jun 2008 04:03:10 +0000 #comment-21373 Surely ’20th cousin’ is actually a very distant relationship (assuming it means a someone with one common ancestor 20 generations back). 
 
In a population not composed of recent migrants, most people will be related by numerous moderately distant ancestors, sufficient to give an aggregate relatedness equivalent to about second-cousins. 
 
But as I pointed out in one of my notes on Sewall Wright, if relatedness between two individuals is only ‘average’ for the population they belong to, there is no correlation or regression between them relative to that population, therefore r for the purposes of Hamilton’s Rule is zero.

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