Grant’s gazelles have recently been proposed to be a species complex comprising three highly divergent mtDNA lineages (Nanger granti, N. notata and N. petersii). The three lineages have non-overlapping distributions in East Africa, but without any obvious geographical divisions, making them an interesting model for studying the early stage evolutionary dynamics of allopatric speciation in detail. Here we use genomic data obtained by restriction site-associated (RAD) sequencing of 106 gazelle individuals to shed light on the evolutionary processes underlying Grant's gazelle divergence, to characterize their genetic structure and to assess the presence of gene flow between the main lineages in the species complex. We date the species divergence to 134,000 years ago, which is recent in evolutionary terms. We find population subdivision within N. granti, which coincides with the previously suggested two subspecies, N.g. granti and N.g. robertsii. Moreover, these two lineages seem to have hybridized in Masai Mara. Perhaps more surprisingly given their extreme genetic differentiation, N. granti and N. petersii also show signs of prolonged admixture in Mkomazi, which we identified as a hybrid population most likely founded by allopatric lineages coming into secondary contact. Despite the admixed composition of this population, elevated X-chromosomal differentiation suggests that selection may be shaping the outcome of hybridization in this population. Our results therefore provide detailed insights into the processes of allopatric speciation and secondary contact in a recently radiated species complex.

BAM files with RAD sequencing data of 106 Grant's gazelle and 4 Thomson's gazelle mapped to the goat reference genome bosTau8. Contains also scripts used to generate all analyses starting from these BAM files for the publication "Vicariance followed by secondary gene flow in a young gazelle species complex".

bamfiles.zip: contains the 110 bam files.

README.md has information on how to use the scripts.

infoFiles.zip contains lists with sample information corresponding to bam files and variants excluded during QC

scripts.zip contains the scripts, including model specification files for all models used with fastsimcoal2 and qpGraph

Raw sequence data availabe in SRA accession PRJNA673069.