Tag Archives: population genetics

Genomics of Hybridization – Part II, Top three of 2015

Death Valley pupfishes (Cyprinodon) are among the most endangered vertebrates on earth, with small inbred populations, with heavy risks of extinction in extreme environments. Martin et al. (2016) in a recent publication quantify diversity and adaptability in a very small population … Continue reading

Posted in bioinformatics, conservation, genomics, methods, natural history, next generation sequencing, population genetics, R, software, speciation, STRUCTURE, theory | Tagged , , , , | Leave a comment

Genomics of Hybridization – Part 1

In a series of articles, I will discuss recent advances in hybridization genomics – the fundamentals of adaptive introgression, “islands of speciation”, differential gene flow, and linked selection have been discussed in my previous posts (here, here, and also at … Continue reading

Posted in adaptation, evolution, genomics, methods, natural history, next generation sequencing, pedigree, phylogenetics, plants, population genetics, RNAseq, software, speciation, species delimitation, STRUCTURE, theory, transcriptomics | Tagged , , , , , , | Leave a comment

Earthquakes and rapid evolution

The 1964 Alaskan earthquake was landscape-altering in creating/uplifting numerous islands in the Gulf of Alaska, providing an ideal system to study adaptive evolution of diversification in affected species – the threespine stickleback (Gasterosteus aculeatus) being a widely studied example. In … Continue reading

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Long distance dispersal of modern humans outside of Africa

Long distance dispersal (LDD) has long known to be an artifact of human migrations out of Africa. However, the effects of LDD on modern human diversity, and models of LDD in human colonization are yet to be characterized. Using an … Continue reading

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Anti-predatory adaptations in sticklebacks and butterflies

Two recent studies analyze character shifts in response to different selection regimes – (1) Mullerian mimicry wing patterns in Heliconius butterflies, and (2) anti-intraguild-predator adaptations in armor and shape of threespine sticklebacks. Hoyal Cuthill and Charleston 2015 Wing patterning genes … Continue reading

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Clinal genomic variation in Drosophila species

Two recent manuscripts describe adaptive evolutions to clinal/latitudinal variations in Drosophila species to supplement a growing wealth of recent studies on geographic variation and adaptive evolution in natural populations of fruitflies (eg. see Kao et al. 2015, Zhao et al. … Continue reading

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2D Posterior Density Plots in R

I have been grappling with visualizing two dimensional histograms of posterior density distributions of parameters, as estimated by one of your favorite programs – IMa2, MIGRATE-n, MSVAR, etc. All these programs print out distributions of estimated parameters, and here’s a … Continue reading

Posted in bioinformatics, howto, population genetics, R, software | Tagged , , , | 1 Comment

Genomics of domestication in chicken and cattle

Two recent studies attempt to understand the process of adaptive evolution in domestication and artificial selection by characterizing (a) sweeps, and their association with phenotypes in extant hybrid lines (Sheng et al. 2015), and (b) phylogenomic position of an extinct … Continue reading

Posted in adaptation, bioinformatics, domestication, evolution, genomics, natural history, Paleogenomics, phylogeography, population genetics, selection, speciation, STRUCTURE | Tagged , , , , , , | 1 Comment

On false positives in Isolation with Migration analyses

The IM suite of tools (IM, IMa, IMa2, IMa2p, etc.) are used widely by molecular ecologists at large for the analyses and estimation of ancestral demography under an Isolation with Migration (IM) model. However, these tools come with fundamental assumptions … Continue reading

Posted in evolution, genomics, howto, IMa2, methods, Molecular Ecology views, natural history, population genetics, software, theory | Tagged , , , , , , , | 1 Comment

On background selection in Ficedula flycatchers

Several recent studies (including those I wrote about last week) use genome-wide scans of differentiation to understand evolutionary mechanisms behind high or low divergence. However, there has been contentious support for and against these differentiation islands being due to differential … Continue reading

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