Biology subjects

Burrell, A. S.

Publications and source records attributed to Burrell, A. S..

4 recordsLinked to original sources

bioRxiv2023

Genome-wide coancestry reveals details of ancient and recent male-driven reticulation in baboons

Baboons (genus Papio) are a morphologically and behaviorally diverse clade of catarrhine monkeys that have experienced hybridization between phenotypically and genetically distinct phylogenetic species. We used high coverage whole genome sequences from 225 wild baboons representing 19 geographic localities to investigate population genomics and inter-species gene flow. Our analyses provide an expanded picture of evolutionary reticulation among species and reveal novel patterns of population structure within and among species, including differential admixture among conspecific populations. We describe the first example of a baboon population with a genetic composition that is derived from three distinct lineages. The results reveal processes, both ancient and recent, that produced the observed mismatch between phylogenetic relationships based on matrilineal, patrilineal, and biparental inheritance. We also identified several candidate genes that may contribute to species-specific phenotypes. One-Sentence SummaryGenomic data for 225 baboons reveal novel sites of inter-species gene flow and local effects due to differences in admixture.

evolutionary biology↗

bioRxiv2021

High-altitude adaptation and incipient speciation in geladas

Survival at high altitude requires adapting to extreme conditions such as environmental hypoxia. To understand high-altitude adaptations in a primate, we assembled the genome of the gelada (Theropithecus gelada), an endemic Ethiopian monkey, and complemented it with population resequencing, hematological, and morphometric data. Unexpectedly, we identified a novel karyotype that may contribute to reproductive isolation between gelada populations. We also identified genomic elements including protein-coding sequences and gene families that exhibit accelerated changes in geladas and may contribute to high-altitude adaptation. Our findings lend insight into mechanisms of speciation and adaptation while providing promising avenues for functional hypoxia research.

genomics↗

bioRxiv2019

Genomic signatures of extreme body size divergence in baboons

Kinda and gray-footed chacma baboons occupy opposite extremes of the body size distribution in extant baboons (genus Papio). In order to detect signatures of natural selection in these two species, we genotyped 24,790 genome-wide autosomal SNPs from populations of Zambian baboons using double digest RADseq. We scanned the genome for evidence of selection by identifying regions with extreme differentiation between populations. We find evidence of selection on body size influencing multiple genes in one or both species, including FGF1, ATXN2, and PRKCE. We also find an enriched signal of selection associated with biological processes involved in multicellular organism growth and development, cell proliferation and cell growth, nutrient metabolism, and chondrocyte differentiation. Finally, we find that selection has impacted components of the CCKR signaling pathway, which regulates food intake and metabolism, and the JAK/STAT signaling pathway, which mediates the effect of cytokine signals on processes including epiphyseal chondrocyte proliferation essential for longitudinal bone growth. Our findings highlight promising avenues for future studies disentangling the genetic architecture of body size in primates including humans.

evolutionary biology↗

bioRxiv2019

Genome-wide ancestry and introgression in a Zambian baboon hybrid zone

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 ba-boon 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 eluci-date the dynamics of introgressive hybridization in a primate system while highlighting genes and pathways under selection.

evolutionary biology↗