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K. Roeder 11110.3 Some collaborative projectsI started my search for collaborators as a graduate student. Because I hadstudied so much biology and chemistry as an undergraduate, it struck methat all those years of training should not be ignored. I decided to hang outwith the evolutionary biology graduate students, attending their seminars andsocial events. In time I found an opportunity to collaborate on a project. Theresearch involved plant paternity. Little did I know that this would be the firstjoint paper in a long collaborative venture with Bernie Devlin. Years later wemarried and to date we have co-published 76 papers. Since the early yearsBernie’s interests have evolved to human genetics and statistical genetics,dovetailing very nicely with my own. So while I can’t recommend everyonemarry a collaborator, it has benefitted me immensely.Genetic diversity has been a theme for much of our joint research. Toprovide an example of how an initial investment in a research topic can leadfrom one paper to another, I will explain this line of research. But first, topromote understanding of this section, I will provide a very brief primer ongenetics. An allele is an alternative form of DNA, located at a specific positionon a chromosome. The allele frequency is the probability distribution of thealleles among individuals in the population. Frequently this distribution isestimated using a sample of alleles drawn from the reference database. Forexample, sickle cell anemia is due to a single base pair change (A to a T)in the beta-globin gene. The particular allelic form with a T is extremelyrare in Caucasian populations, but more common in African populations. Thereason for this difference in allele frequencies is that the T form provides somebenefit in resisting malaria. Thus the selective advantage of the T allele wouldbe felt more strongly in African populations, causing a shift in frequencydistribution. Finally, to complete the genetics primer, at each location, a pairof alleles is inherited, one from each parent (except, of course, on chromosomeX). By Mendel’s law, a parent passes on half of their genetic material to anoffspring. It is through these simple inheritance rules that numerous geneticrelationships can be inferred (such as paternity).In our first project we needed to infer the paternal source of inheritancefor all the seeds produced by a plant. The maternal source is obvious, becausethe seeds are produced on the maternal plant. While plants don’t pay alimony,paternity is interesting for other reasons. Plants are obviously stationary, butthe paternal genes are transmitted via pollen by natural vectors (butterfliesand such), so genetic material moves much more widely than expected. Itis important to know how far genes move naturally so that we can predictthe consequences of genetic engineering. From a statistical point of view, forplants, paternity is inferred just as in humans. When a child matches thealleged father at half her alleles, then he is not excluded for paternity. And if