|Moderator: Robert Fleischer, Smithsonian Conservation Biology Institute and National Zoological Park|
4.1 16:15 The impact of conservation genomics on genetic rescue of endangered species: the critical role of viable cell collections. Oliver Ryder *, San Diego Zoo
Comparative genomics studies are revolutionizing the understanding of the process of speciation, the persistence of species, and extinction risk. The swift development of increasingly sophisticated genome assemblies from a rapidly expanding list of species allows assessments of genome-wide genetic variation that reveal population history, patterns of gene flow, admixture, and loci that contribute to environmental adaptations. Access to specimens appropriate for development of high-quality genome assemblies is crucial to the progress in genomics studies across taxa and to focused efforts to apply whole genome sequencing studies to conservation of threatened and endangered species. The viable cell collections of San Diego Zoo Global's Frozen Zoo® have contributed to recent advances in the field of biodiversity genomics and phylogenomics through the Genome 10K project and other initiatives. Viable cell collections have potential to contribute to genetic rescue that can restore genetic variation to critically small populations. Cellular-based technologies, including induced pluripotent stem cells (iPSCs) may provide options for supporting persistence of critically small populations. As one example, preventing the extinction of the northern white rhinoceros, Ceratotherium simum cottoni, a subspecies reduced to a living population of three closely related individuals, will depend on the application of advanced genetic, cellular, and reproductive technologies (Saragusty, et al., 2016). Studies of genome-wide variation of white rhinoceros subspecies can shed light on the potential for genetic rescue using cryobanked cell cultures. This work supports expanded efforts to collect and preserve viable somatic cells from threatened species to augment options for their conservation.
4.2 16:35 The Measurement of Adaptive and Deleterious Variation as Goals for Conservation Genomics. Robert Wayne *, University of California- Los Angeles
A traditional aim of conservation genetics has been the preservation of overall levels of genetic diversity and the evolutionary legacy of species. However, more specifically pertinent to the persistence of populations is the maintenance of heritable adaptive variation that enables local adaptation and provides a hedge against future environmental changes. In contrast, the accumulation of deleterious variation decreases the survivorship and fecundity of individuals and therefore threatens population persistence. Because it has only recently been possible to roughly assess adaptive and deleterious variation genome wide in natural populations, there is not yet a conservation framework for comparing and utilizing these data. I illustrate this problem by discussing the relative levels of putative adaptive diversity across gray wolf populations in North America and several issues regarding the application of these data to conservation. I then discuss deleterious variation in more detail, since its quantification has been relatively overlooked in natural populations. Specifically, I present complete genome data on small populations of island foxes, living on coastal islands in Southern California. Despite accumulation of deleterious variants and a strong decrease in the efficacy of natural selection, the island populations have persisted for thousands of years. However, the expected accumulation of developmental abnormalities has not occurred in the island populations and we hypothesize that unique characteristics of their demographic history may have allowed purging of genetic load early in the history of the population. Finally, I more broadly discuss deleterious variation and its importance in conservation genomic surveys.
4.3 16:55 Genomic Consequences of Population Decline in the Endangered Florida Scrub-Jay. Chen N, University of California- Davis; Cosgrove E, Cornell University; Bowman R, Archbold Biological Station; Aguillon S, Cornell University ; Graham C, Cornell University ; Fitzpatrick J, University of California- Davis; Clark A*, Cornell University
Long-term legacy projects that have recorded full pedigree information afford a remarkable opportunity to apply genomics technologies to understand population-level processes. This information can be especially important in threatened populations. Understanding the population genetic consequences of shrinking population size is important for conserving the many species worldwide facing severe decline. Here we assess temporal variation in gene flow, inbreeding, and fitness using longitudinal genomic and demographic data from a population of federally Threatened Florida Scrub-Jays (Aphelocoma coerulescens). We exhaustively sampled and genotyped the study population over two decades and made extensive use of the genetic and pedigree data to draw inferences about the relationships between allelic variation, overall heterozygosity, fitness components, dispersal and inbreeding depression. These birds are remarkably short dispersers, and leave genetic signatures of isolation-by-distance at 1 km scales that are consistent with dispersal curves inferred directly from the pedigree records. Regional population declines reduced immigration into the study population since 1995, resulting in increased levels of inbreeding and concomitant inbreeding depression, even as the population remained demographically stable. Our results suggest that small peripheral populations play a vital role in preserving genetic diversity of larger and seemingly stable populations. These findings highlight the value of maintaining the connectivity of small peripheral populations and provide many other insights for genetic conservation of this species.
|17:15 Questions & Discussion|
|17:20 - 17:30 Wrap - up|
|19:00 - 21:00 Reception in Rotunda, NMNH|