Author Archives: Arun Sethuraman

The Truth

Posted on 17 Mar, 2016 by Arun Sethuraman

Spoiler Alert: I’ve taken plenty of care to try and not spill the beans on any plotlines, but you have been forewarned that there may be some aspects of the science that’s discussed on the show that I attempt to … Continue reading →

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Geographical Heat Maps in R

Posted on 3 Mar, 2016 by Arun Sethuraman

I go crazy for fancy data visualizations in R, and a figure in a recent publication has had me wondering if there is an easy way to incorporate density distributions (or as in their case, a distribution of f4 statistics, … Continue reading →

Posted in bioinformatics, howto, R, software | Tagged , | 2 Comments

The Neanderthal admixture plot thickens…

Posted on 25 Feb, 2016 by Arun Sethuraman

Previous studies of archaic admixture from Altai Neanderthals and Denisovans into modern humans outside of Africa have put forth several lines of evidence for gene flow from Neanderthals into common ancestors of Eurasian populations, from Denisovans into ancestors of modern … Continue reading →

Posted in bioinformatics, evolution, genomics, mutation, natural history, next generation sequencing, Paleogenomics, population genetics, speciation | Tagged , , , | 2 Comments

Genomics of Hybridization – Part II, Top three of 2015

Posted on 28 Jan, 2016 by Arun Sethuraman

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

Posted on 21 Jan, 2016 by Arun Sethuraman

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

Posted on 7 Jan, 2016 by Arun Sethuraman

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 →

Posted in adaptation, evolution, genomics, natural history, next generation sequencing, phylogeography, population genetics, selection, STRUCTURE | Tagged , , , , , , | Leave a comment

Long distance dispersal of modern humans outside of Africa

Posted on 10 Dec, 2015 by Arun Sethuraman

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 →

Posted in evolution, genomics, natural history, population genetics | Tagged , , , , , | 2 Comments

Anti-predatory adaptations in sticklebacks and butterflies

Posted on 23 Nov, 2015 by Arun Sethuraman

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 →

Posted in adaptation, Coevolution, evolution, genomics, natural history, phylogenetics, phylogeography, population genetics, selection, speciation | Tagged , , , | Leave a comment

Clinal genomic variation in Drosophila species

Posted on 12 Nov, 2015 by Arun Sethuraman

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

Posted on 6 Nov, 2015 by Arun Sethuraman

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