BACKGROUND

Baboons (genus ) and geladas () are now generally recognized as close phylogenetic relatives, though morphologically quite distinct and generally classified in separate genera. Primate specific retrotransposons are well-established genomic markers for the study of phylogenetic and population genetic relationships. We previously reported a computational reconstruction of phylogeny using large-scale whole genome sequence (WGS) analysis of insertion polymorphisms. Recently, high coverage WGS was generated for The objective of this study was to apply the high-throughput "poly-Detect" method to computationally determine the number of insertion polymorphisms shared by and , and vice versa, by each individual species and . Secondly, we performed locus-specific polymerase chain reaction (PCR) assays on a diverse DNA panel to complement the computational data.

RESULTS

We identified 27,700 insertions from WGS that were also present among six species, with nearly half (12,956) remaining unfixed among 12 individuals. Similarly, each of the six species had species-indicative insertions that were also present in . In general, shared more insertion polymorphisms with than did any of the other five species. PCR-based genotype data provided additional support for the computational findings.

CONCLUSIONS

Our discovery that several thousand insertion polymorphisms are shared by and baboons suggests a much more permeable reproductive barrier between the two genera then previously suspected. Their intertwined evolution likely involves a long history of admixture, gene flow and incomplete lineage sorting.