Change in Recessive Lethal Alleles Frequency in Inbred Populations

Change in Recessive Lethal Alleles Frequency in Inbred Populations
Arindam RoyChoudhury
(Submitted on 10 Apr 2013)

In a population practicing consanguineous marriage, rare recessive lethal alleles (RRLA) have higher chances of affecting phenotypes. As inbreeding causes more homozygosity and subsequently more deaths, the loss of individuals with RRLA decreases the frequency of these alleles. Although this phenomenon is well studied in general, here some hitherto unstudied cases are presented. An analytical formula for the RRLA frequency is presented for infinite monoecious population practicing several different types of inbreeding. In finite diecious populations, it is found that more severe inbreeding leads to quicker RRLA losses, making the upcoming generations healthier. A population of size 10,000 practicing 30% half-sib marriages loses more than 95% of its RRLA in 100 generations; a population practicing 30% cousin marriages loses about 75% of its RRLA. Our findings also suggest that given enough resources to grow, a small inbred population will be able to rebound while losing the RRLA.

1 thought on “Change in Recessive Lethal Alleles Frequency in Inbred Populations

  1. I have the impression that the author is totally ignoring new mutations, generally harmful, especially in the most unstable equilibrium of an inbred population and also treating genes as discrete units when in most cases they seem to interact with each other in complex ways, being in any case a very large plurality and not abstractly simple mendelian units. What happens if the deleterious allele is only responsible in (for example) 10% of the deadly effects and there are other nine alleles necessary for the other 90%? I’d say that in that case the inbred population would be much worse off because diversity should be an asset fencing off the combination of these ten prblematic alleles, whose negative effect is only cumulative.

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