Surprising fitness consequences of GC-biased gene conversion. II. Heterosis.
Heterosis is a widespread phenomenon corresponding to the increase in fitness following crosses between individuals from different populations or lines relative to their parents. Its genetic basis has been a topic of controversy since the early 20th century. The masking of recessive deleterious mutations in hybrids likely explains a substantial part of heterosis. The dynamics and consequences of these mutations have thus been studied in depth. Recently, it was suggested that GC-biased gene conversion (gBGC) might strongly affect the fate of deleterious mutations and may have significant fitness consequences. gBGC is a recombination-associated process mimicking selection in favor of G and C alleles, which can interfere with selection, for instance by increasing the frequency of GC deleterious mutations. I investigated how gBGC could affect the amount and genetic structure of heterosis through an analysis of the interaction between gBGC and selection in subdivided populations. To do so, I analyzed the infinite island model both by numerical computations and by analytical approximations. I showed that gBGC might have little impact on the total amount of heterosis but could greatly affect its genetic basis.
Glémin
Sylvain
S
Institut des Sciences de l'Evolution, Université Montpellier II, 34095 Montpellier, France. glemin@univ-montp2.fr
D001482:Base Composition / Q000235:genetics* / Q000502:physiology*; D005785:Gene Conversion / Q000235:genetics* / Q000502:physiology*; D056426:Genetic Loci / Q000235:genetics; D006801:Humans; D006823:Hybrid Vigor / Q000235:genetics* / Q000502:physiology*; D008957:Models, Genetic; D009154:Mutation; D012641:Selection, Genetic