Selection and biased gene conversion in a multigene family: consequences of interallelic bias and threshold selection

In a previous paper, I investigated the interactions in a gene family of additive selection and biased gene conversion in a finite population when conversion events are rare. Here I extend my "weak-conversion limit" model by allowing biased interallelic conversion (conversion between allel...

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Bibliographic Details
Published in:Genetics (Austin) 1986-03, Vol.112 (3), p.699-716
Main Author: WALSH, J. B
Format: Article
Language:English
Subjects:
Alleles
Animals
Biological and medical sciences
Fundamental and applied biological sciences. Psychology
Gene Conversion
Genetic Linkage
Genetics of eukaryotes. Biological and molecular evolution
Humans
Investigations
Mathematics
Models, Genetic
Population genetics, reproduction patterns
Probability
Selection, Genetic
Theories and miscellaneous
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Summary:In a previous paper, I investigated the interactions in a gene family of additive selection and biased gene conversion in a finite population when conversion events are rare. Here I extend my "weak-conversion limit" model by allowing biased interallelic conversion (conversion between alleles at the same locus) of arbitrary frequency and various threshold selection schemes for rare interlocus conversion events. I suggest that it is not unreasonable for gene families to experience threshold fitness functions, and show that certain types of thresholds can greatly constrain the rate at which advantageous alleles are fixed as compared to other fitness schemes, such as additive selection. It is also shown that the double sampling process operating on a gene family in a finite population (sampling over the number of genes in the gene family and over the number of individuals in the population) can have interesting consequences. For selectively neutral alleles that experience interallelic bias, the probability of fixation at each single locus may be essentially neutral, but the cumulative effects on the entire gene family of small departures from neutrality can be significant, especially if the gene family is large. Thus, in some situations, gene families can respond to directional forces that are weak in comparison to drift at single loci.
ISSN:0016-6731
1943-2631
1943-2631
DOI:10.1093/genetics/112.3.699