14 research outputs found
Strong artificial selection in domestic mammals did not result in an increased recombination rate
Recombination rates vary in intensity and location at the species, individual, sex and
chromosome levels. Despite the fundamental biological importance of this process, the
selective forces that operate to shape recombination rate and patterns are unclear. Domestication
offers a unique opportunity to study the interplay between recombination and selection,
particularly due to Hill-Robertson interference, which should be important when many linked
loci are repeatedly the target of selection. In domesticates, intense selection for particular traits
is imposed on small populations over many generations, resulting in organisms that differ,
sometimes dramatically, in morphology and physiology from their wild ancestor. Although
earlier studies suggested increased recombination rate in domesticates, a formal comparison of
recombination rates between domestic mammals and their wild congeners was missing. In
order to determine broad-scale recombination rate, we used immunolabeling detection of MLH1
foci as crossover markers in spermatocytes in three pairs of closely related wild and domestic
species (dog and wolf, goat and ibex, sheep and mouflon). In the three pairs, and contrary to
previous suggestions, our data show that contemporary recombination rate is higher in the wild
species. Subsequently, we inferred recombination breakpoints in sequence data for 16 genomic
regions in dogs and wolves, each containing a locus associated with a dog phenotype potentially
under selection during domestication. No difference in the number and distribution of
recombination breakpoints was found between dogs and wolves. We conclude that our data
indicate that strong directional selection did not result in changes in recombination in domestic
mammals, and that both upper and lower bounds for crossover rates may be tightly regulatedPeer reviewe