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Understanding the process and consequences of hybridization is one of the major challenges in evolutionary biology. A growing body of literature has reported evidence of ancient hybridization events or natural hybrid zones in primates, including humans; however, we still have relatively limited knowledge about the pattern and history of admixture because there have been little studies that simultaneously achieved genome-scale analysis and a geographically wide sampling of wild populations. Our study applied double-digest restriction site-associated DNA sequencing to samples from the six localities in and around the provisional hybrid zone of rhesus and long-tailed macaques and evaluated population structure, phylogenetic relationships, demographic history, and geographic clines of morphology and allele frequencies. A latitudinal gradient of genetic components was observed, highlighting the transition from rhesus (north) to long-tailed macaque distribution (south) as well as the presence of one northern population of long-tailed macaques exhibiting unique genetic structure. Interspecific gene flow was estimated to have recently occurred after an isolation period, and the migration rate from rhesus to long-tailed macaques was slightly greater than in the opposite direction. Although some rhesus macaque-biased alleles have widely introgressed into long-tailed macaque populations, the inflection points of allele frequencies have been observed as concentrated around the traditionally recognized interspecific boundary where morphology discontinuously changed; this pattern was more pronounced in the X chromosome than in autosomes. Thus, due to geographic separation before secondary contact, reproductive isolation could have evolved, contributing to the maintenance of an interspecific boundary and species-specific morphological characteristics., (© 2020 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2020 European Society For Evolutionary Biology.)

Background: The genetic composition of cynomolgus macaques used in biomedical research is not as well-characterized as that of rhesus macaques., Methods: Populations of cynomolgus macaques from Sumatra, Corregidor, Mauritius, Singapore, Cambodia, and Zamboanga were analyzed using 24 STRs., Results: The Sumatran and Cambodian populations exhibited the highest allelic diversity, while the Mauritian population exhibited the lowest. Sumatran cynomolgus macaques were the most genetically similar to all others, consistent with an Indonesian origin of the species. The high diversity among Cambodian animals may result from interbreeding with rhesus macaques. The Philippine and Mauritian samples were the most divergent from other populations, the former due to separation from the Sunda Shelf by deepwater and the latter due to anthropogenic translocation and extreme founder effects., Conclusions: Investigators should verify their research subjects' origin, ancestry, and pedigree to minimize risks to biomedical experimentation from genetic variance stemming from close kinship and mixed ancestry as these can obscure treatment effects., (© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Regional populations of rhesus and long-tailed macaques exhibit fundamental differences in mitochondrial DNA, short tandem repeat and single nucleotide polymorphism variation between mainland and insular Southeast Asian populations. Some studies have revealed genetic admixture between these species due to natural hybridization and human-assisted intercrosses. A quantitative real-time PCR (qPCR) assay was developed to efficiently determine the species of origin of a macaque biological sample, and to quantify the species-specific template DNA. Prior knowledge of species identity and DNA concentrations are crucial for maintaining cost-effective methods and accurate DNA analysis. DNA from 109 regionally representative rhesus and long-tailed macaques was qPCR amplified to determine the species and template quantities. Of the 19 Vietnamese long-tailed macaques, 3 samples were discovered to be hybrids., (Copyright © 2011 S. Karger AG, Basel.)

Partial sequences from mitochondrial (mt) 12S and 16S rRNA genes were analyzed to characterize diversity among captive rhesus macaques (Macaca mulatta) originating from various geographic regions. Several nested clades, defined by closely related haplotypes, were identified, suggesting considerable genetic subdivision, probably relics from heterogeneous origins, founder effects, and genetic drift, followed by breeding isolation. The rhesus matrilineages from India differed discretely and markedly from Chinese matrilineages; approximately 90% of the genetic heterogeneity among the combined samples of Indian and Chinese rhesus macaques studied here was due to country of origin. In addition, mtDNA sequences from macaques of China were more diverse than those from rhesus macaques of India, an outcome consistent with China's greater subspecies diversity and with nuclear genotype distributions. Otherwise, the distribution of mtDNA variation within rhesus macaques of China, and especially within those of India, exhibited far less structure and did not conform to a simple isolation-by-distance model. As the demand for genetically heterogeneous and well-characterized rhesus macaques for biomedical-based research increases, mtDNA haplotypes can be useful for genetically defining, preserving maximal levels of genetic diversity within, and confirming the geographic origin of captive breeding groups of rhesus macaques.