BRAIN Initiative: Marmosets for Neuroscience Research
Greg Farber, Ph.D.
Office of Technology Development and Coordination
Both the BRAIN 2025 report as well as the draft report from the BRAIN Working Group 2.0 mention the need for research involving non-human primates to help us understand various circuits in the primate brain. While a number of different non-human primates have been used in neuroscience research, the macaque is clearly the most frequently used model today, but the marmoset is emerging as a useful model. This concept focuses only on the marmoset. One of the goals of this concept is to increase the number of marmosets that are available to the neuroscience research community. The second major goal of this concept is to continue the development of the tools and technologies for transgenic manipulation and characterization of marmosets.
The common marmoset is native to northeast Brazil, where it is non-endangered, but is subject to strict export laws. Its fertility rate, fast maturity, rich social behavior, and small size relative to other primates have made it an increasingly interesting choice for biomedical research. For neuroscientists, the relatively small marmoset brain size and lissencephalic cortex make this an attractive model system. Success in producing transgenic animals has furthered interest, driving a major increase in demand for animals.
One of the major barriers to the use of marmosets in neuroscience research is the difficulty that researchers are having in obtaining animals. Two recent National Academy Meetings have documented that issue (http://nationalacademies.org/hmd/Reports/2019/transgenic-neuroscience-research-exploring-the-scientific-opportunities-afforded-by-new-nonhuman-primate-models-proceedings.aspx and https://www.nap.edu/catalog/25356/care-use-and-welfare-of-marmosets-as-animal-models-for-gene-editing-based-biomedical-research). The first major goal of this concept is to increase the number of marmosets that are available to the neuroscience research community, to coordinate the distribution of those animals, and to help the marmoset colony managers answer pressing questions about the best way to raise and care for marmosets.
The second major goal of this concept is to continue the development of the tools and technologies for transgenic manipulation and characterization of marmosets. Several laboratories have been working in this space, but the current technologies are not robust.
It is important to mention that the focus of this concept on marmosets does not discount the importance of other primates, especially macaques. At this time, the population of marmosets in the United States is around 2,500 individuals. In contrast, there are likely around 90,000 macaques. The problems that neuroscience researchers are having in obtaining marmosets combined with information received from the primate centers and about commercial sources strongly suggests that this unavailability will continue unless NIH takes action.