Scientists have long recognized that both wild and captive populations of endangered species are at a high risk for loss of genetic diversity due to their rarity. With small or isolated populations, genetic diversity can be lost through stochastic genetic drift or breeding between close relatives. Therefore, proper management of captive populations is critical to ensure long-term sustainability. The struggle, however, is how to efficiently and economically collect and analyze high-resolution genetic data that can fill the knowledge information gaps in effective breeding practices.
Haw Chuan Lim, Associate Professor in George Mason’s College of Science, Department of Biology, saw an opportunity to combine the experience and knowledge of other experts in the field to develop a novel genomic tool to address this issue.
The researchers created and validated the application of a novel genetic probe-set. It was used to generate data from different types of genetic markers with complementary features such as ease of genotyping, presence throughout the genome, and high information content. The team reasoned that a study conducted on one animal could provide a platform for application to other endangered species.
The Eastern mountain bongo, a critically imperiled ungulate native to Kenya, was identified as a test species. Although fewer than 140 bongos remain In the wild, there are approximately 160 bongos in U.S. zoos and several hundred more on private ranches. As such, breeding and transfer strategies that increase genetic diversity and reduce inbreeding of captive animals are critical for the survival of the species.
The 4-VA@Mason Advisory Board saw the value in Lim’s proposal, “Development of a novel genotyping panel for powerful and cost-effective evaluations of population structure and kinship in the critically endangered mountain bongo” and approved it for funding.
GMU researchers, Lim and his PhD student, Karen Holm, assembled their team — Aakrosh Ratan, Assistant Professor, University of Virginia; Klaus-Peter Koepfli, Senior Research Scientist, Smithsonian Mason School of Conservation; and Budhan Pukazhenthi, Research Physiologist, Smithsonian Conservation Biology Institute. 4VA funding was used to purchase the necessary supplies, reagents and equipment including DNA tests and probe sets.
Four types of samples—whole blood, fecal swabs, tissues, and extracted DNA—from 39 North American conservation centers and zoos were collected to begin the project. This resulted in a total of 207 samples from both current and historical ex situ populations (populations outside of the native ranges). They evaluated the effectiveness of the probe-set in generating high-quality genetic data from different sample types and for different genetic marker types. The data obtained are now being accessed for their ability to produce accurate information on animal kinship, genetic diversity and population structure, which will ultimately be used to guide precise captive breeding programs.
Some preliminary data, as well as a chromosome-level genome assembly, have already been published by the National Center for Biotechnology Information and at https://www.dnazoo.org/copy-of-assemblies/tragelaphus_eurycerus_isaaci. A high-quality genome serves as an invaluable resource for species conservation because it can be used for many types of research such as those focused on detecting deleterious mutations. All results from this study will ultimately contribute to the Association of Zoos and Aquariums Species Survival Plan for the species.
Concludes Lim, “The 4-VA@Mason funding got us started, and now we have obtained external funding to move the research even further.”