Genome-wide ancestry and introgression in a Zambian baboon hybrid zone
PDF of preprint available from bioRxiv
Abstract: Hybridization in nature offers unique insights into the process of natural selection in incipient species and their hybrids. In order to evaluate the patterns and targets of selection, we examine a recently discovered baboon hybrid zone in the Kafue River valley of Zambia, where Kinda baboons (Papio kindae) and gray-footed chacma baboons (P. ursinus griseipes) coexist with hybridization. We genotyped baboons at 14,962 variable genome-wide autosomal markers using double-digest RADseq. We compare ancestry patterns from this genome-wide dataset to previously reported ancestry from mitochondrial-DNA and Y-chromosome sources. We also fit a Bayesian genomic cline model to scan for genes with extreme patterns of introgression. We show that the Kinda baboon Y chromosome has penetrated the species boundary to a greater extent than either mitochondrial DNA or the autosomal chromosomes. We also find evidence for overall restricted introgression in the JAK/STAT signaling pathway. Echoing results in other species including humans, we find evidence for enhanced and/or directional introgression of immune-related genes or pathways including the toll-like receptor pathway, the blood coagulation pathway, and the LY96 gene. Finally we show enhanced introgression and excess chacma baboon ancestry in the sperm tail gene ODF2. Together, our results elucidate the dynamics of introgressive hybridization in a primate system while highlighting genes and pathways under selection.
Two baboon preprints in one day! 🐵🐵 Led by @kchiou, both focus on the smallest baboon which we got to study in Zambia. First is on adaptive body size evolution (https://t.co/rne1t2cs9L), second is on hybridization w/ bigger (& uglier) chacma baboons (https://t.co/TxNeISOPE1). pic.twitter.com/SdtJp6nzWr
— Christina Bergey (@bergeycm) March 18, 2019
New genomic analysis of the Kinda x chacma hybrid zone in Zambia! Our second of two preprints posted today! https://t.co/UU2SKymyaP. With @bergeycm, @ToddDisotell, and other fantastic colleagues. pic.twitter.com/1Uo6iK20xZ
— Kenny Chiou (@kchiou) March 17, 2019