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Chromosomal inversions and the reproductive isolation of species
Recent genetic studies have suggested that many genes contribute to differences between closely related species that prevent gene exchange, particularly hybrid male sterility and female species preferences. We have examined the genetic basis of hybrid sterility and female species preferences in Drosophila pseudoobscura and Drosophila persimilis , two occasionally hybridizing North American species. Contrary to findings in other species groups, very few regions of the genome were associated with these characters, and these regions are associated also with fixed arrangement differences (inversions) between these species. From our results, we propose a preliminary genic model whereby inversions may contribute to the speciation process, thereby explaining the abundance of arrangement differences between closely related species that co-occur geographically. We suggest that inversions create linkage groups that cause sterility to persist between hybridizing taxa.
Humans and their closest evolutionary relatives, the chimpanzees, differ in ∼1.24% of their genomic DNA sequences. The fraction of these changes accumulated during the speciation processes that have separated the two lineages may be of special relevance in understanding the basis of their differences. We analyzed human and chimpanzee sequence data to search for the patterns of divergence and polymorphism predicted by a theoretical model of speciation.
Chromosomal Speciation and Molecular Divergence--Accelerated Evo
This magnificient creature on the left is a copperhead. Copperheads are very common around Arlington. I found this fortunate, but not everybody agrees. Anyhow, this month we co-authored three papers that illustrate how fascinating these and other reptiles are when it comes to their genomes too. On this I hope everybody will agree.
