Search

Background Most cynomolgus macaques ( Macaca fascicularis) used in the United States as animal models are imported from Chinese breeding farms without documented ancestry. Cynomolgus macaques with varying rhesus macaque ancestry proportions may exhibit differences, such as susceptibility to malaria, that affect their suitability as a research model. Methods DNA of 400 cynomolgus macaques from 10 Chinese breeding farms was genotyped to characterize their regional origin and rhesus ancestry proportion. A nested PCR assay was used to detect Plasmodium cynomolgi infection in sampled individuals. Results All populations exhibited high levels of genetic heterogeneity and low levels of inbreeding and genetic subdivision. Almost all individuals exhibited an Indochinese origin and a rhesus ancestry proportion of 5%-48%. The incidence of P. cynomolgi infection in cynomolgus macaques is strongly associated with proportion of rhesus ancestry. Conclusions The varying amount of rhesus ancestry in cynomolgus macaques underscores the importance of monitoring their genetic similarity in malaria research. [ABSTRACT FROM AUTHOR]

The cynomolgus macaque, Macaca fascicularis, was introduced onto the island of Mauritius in the early 17th century. The species experienced explosive population growth, and currently exists at high population densities. Anecdotes collected from nonhuman primate trappers on the island of Mauritius allege that animals from the northern portion of the island are larger in body size than and superior in condition to their conspecifics in the south. Although previous genetic studies have reported Mauritian cynomolgus macaques to be panmictic, the individuals included in these studies were either from the southern/central or an unknown portion of the island. In this study, we sampled individuals broadly throughout the entire island of Mauritius and used spatial principle component analysis to measure the fine-scale correlation between geographic and genetic distance in this population. A stronger correlation between geographic and genetic distance was found among animals in the north than in those in the southern and central portions of the island. We found no difference in body weight between the two groups, despite anecdotal evidence to the contrary. We hypothesize that the increased genetic structure among populations in the north is related to a reduction in dispersal distance brought about by human habitation and tourist infrastructure, but too recent to have produced true genetic differentiation. [ABSTRACT FROM AUTHOR]

Between one and six subspecies of Chinese rhesus macaques (Macaca mulatta) have been proposed based on morphological differences and/or their geographic distribution. In this study, a 489 base pair fragment of the mitochondrial control region was amplified from 230 DNA samples collected from rhesus macaques in the Sichuan province in Western China. The fragment was then sequenced and aligned with 208 sequences from wild rhesus macaques, sampled throughout the species' geographic range in China downloaded from GenBank. Phylogenetic analysis of the 182 unique sequences identified among these samples divided Chinese rhesus macaques into two western haplogroups (haplogroups A and B) and three older eastern haplogroups (haplogroups C, D, and E), whose differentiation probably occurred during the penultimate glacial event. During the warming after the penultimate glacial event, haplogroups A, B, and E rapidly expanded and a relatively young subhaplogroup of haplogroup E, E', limited to Southern China but shared with Vietnamese rhesus macaques, was reintroduced from Indochina during the last glacial event. One haplotype most closely related to subhaplogroup E' probably represents the isolation of Hainan Island, to where it is restricted, from the mainland by the formation of the Qiongzhou Strait approximately 8,500 years ago. The distribution of haplogroups both informs the phylogeographic history of dispersal of Chinese rhesus macaques and has implications for their suitability as animal models in biomedical research. [ABSTRACT FROM AUTHOR]

Rhesus and cynomolgus macaques are frequently used in biomedical research, and the availability of their reference genomes now provides for their use in genome-wide association studies. However, little is known about linkage disequilibrium (LD) in their genomes, which can affect the design and success of such studies. Here we studied LD by using 1781 conserved single-nucleotide polymorphisms (SNPs) in 183 rhesus macaques (Macaca mulatta), including 97 purebred Chinese and 86 purebred Indian animals, and 96 cynomolgus macaques (M. fascicularis fascicularis). Correlation between loci pairs decayed to 0.02 at 1146.83, 2197.92, and 3955.83 kb for Chinese rhesus, Indian rhesus, and cynomolgus macaques, respectively. Differences between the observed heterozygosity and minor allele frequency (MAF) of pairs of these 3 taxa were highly statistically significant. These 3 nonhuman primate taxa have significantly different genetic diversities (heterozygosity and MAF) and rates of LD decay. Our study confirms a much lower rate of LD decay in Indian than in Chinese rhesus macaques relative to that previously reported. In contrast, the especially low rate of LD decay in cynomolgus macaques suggests the particular usefulness of this species in genome-wide association studies. Although conserved markers, such as those used here, are required for valid LD comparisons among taxa, LD can be assessed with less bias by using species-specific markers, because conserved SNPs may be ancestral and therefore not informative for LD.