Attack of the Hybrids

For some reason, I have been collecting links to articles involving hybridization. That, on its own, would call for a massive link dump, but a recent news item makes for a nice contrast. First, the hybrids:

• Where better to start than this review of hybrid speciation -- a topic I've discussed previously. The take home message: we first thought that hybrid speciation only happened in combination with polyploidy in plants, then we found out that hybrid speciation can also occur without polyploidization in plants, and then we discovered that the same thing happens in animals.
• Here's an article on the ecology of hybrid zones. The authors present on a model that incorporates habitat disturbance in contact areas between plant species.
• If modeling hybrid zones isn't your cup of tea and you want data from real populations, here is a paper on a hybrid zone between a threatened species and an invasive species.
• And speaking of environmental effects on hybridization, here is a paper in which the authors report the results of a study to map QTLs for reproductive isolation between two populations of Drosophila mojavensis. Bill Edges and colleagues recorded the mating success of F2 hybrid males with females from one of the populations and analyzed the courtship song of the males (Drosophila males rub their wings together, producing a song that gets the females turned on -- kind of like Barry White for insects). What makes this study unique is that the males were reared on two different host plants -- one native to each of the two populations -- and the effect of each QTL, each host, and the genotype by environment interaction were determined. They found evidence for all three effects on reproductive isolation.
• Helianthus sunflowers are one of the classic models of hybrid zones and hybrid speciation. Laboratory crosses between H. annuus and H. petiolaris show strong reproductive isolation between the two species. Loren Rieseberg and colleagues, however, demonstrate that there is little genetic differentiation between the two species despite the fact that they rarely interbreed. Rieseberg is also author on a paper in which he and his co-authors study the effects of natural selection on hybrid speciation in Helianthus

And, finally, in the antithesis of hybridization, someone told a hammerhead shark to go fuck herself, and she took it literally. Rather than soil her personal gene pool by outcrossing, she produced a pup, not by cloning herself, but by screwing around with meiosis.