The resurgence and genetic implications of New World primates in biomedical research.

There has been a recent resurgence of interest in New World monkeys within the biomedical research community, driven by both the sequencing of the common marmoset (Callithrix jacchus) genome and a growing demand for alternatives to Old World primates. New World monkeys offer attractive advantages over Old World species, including cheaper and simpler husbandry, while still maintaining a greater evolutionary proximity to humans compared with other animal models. Although numerous commonalities across primate species exist, there are also important genetic and reproductive differences that can and should play a critical role in selecting appropriate animal models. Common marmosets in particular have significantly reduced diversity at the major histocompatibility complex (MHC) loci and are born as hematopoietic chimeras. New World primates can make ideal translational models for research, but scientists must necessarily incorporate complete understandings of their genetic and phenotypic differences from humans and other model organisms.