Will Rosenthal and Alex Lewanski both published their MS thesis work in Molecular Ecology this summer. We are thrilled to have these fantastic papers out!

Will’s work used genomic data to assess reproductive fitness of Yellowstone cutthroat trout and hybrids in the North Fork Shoshone River in Northwestern Wyoming. Will finds lower reproductive fitness in individuals with more rainbow trout ancestry, suggesting that decreased hybrid fitness may be contributing to the persistence of some unadmixed Yellowstone cutthroat trout in this river system despite decades of hybridization. He also finds evidence for female preference for mating with fish of similar ancestry. In general, our data show a deficit of late-stage hybrids, suggestive of some form of hybrid breakdown given the extensive hybridization in this system. It is still not a rosy picture for Yellowstone cutthroat trout in this system, as Liz Mandeville’s earlier work showed (we find very few unadmixed Yellowstone cutthroat trout), but Will’s work illuminates some mechanisms to help explain their continued persistence. Check out the full story at Molecular Ecology!

Alex worked on a system near and dear to my heart — including the samples I myself collected as a PhD student. His work follows from one of my PhD chapters, itself published in Molecular Ecology, that reported mtDNA haplotype sharing yet significant microsatellite-based divergence between two cichlid color morphs of the genus Petrochromis. With the power of genomic data, Alex’s work shows that these genetic patterns we observed previously derive from post-divergence admixture between these taxa. Alex’s work used demographic modeling tools to show that this admixture varies geographically across sites where these species co-occur in the Kigoma region of Tanzania. His models support divergence in isolation followed by bidirectional gene flow upon secondary contact. Check it out here in Molecular Ecology!