Phase III Desert Tortoise Genetic Connectivity and Diversity Report
Abstract
The speed and intensity of contemporary anthropogenic change calls into question the capacity of extant species to respond and cope with environmental impacts. One possible response may be evolutionary adaptation; however, uncertainties around adaptive divergence and gene flow limit our abilities to predict their importance for the persistence of sensitive species in fragmented landscapes. The Mojave Desert Tortoise (Gopherus agassizii) is native to the Mojave Desert of North America that has been strongly impacted by habitat fragmentation and human development, and is listed as a threatened species under the ESA. Their slow life history is associated with relatively slow adaptive divergence, casting doubt as to their relative capacity to respond adaptively to environmental change. In this study, we used landscape and population genomic toolsets to explore the interplay between adaptive divergence and gene flow in the Mojave Desert Tortoise. Using genetic samples collected across the species range, we used genotype-environment analyses (GEAs), population genomic analyses, and analyses of population connectivity to characterize neutral and adaptive genetic divergence, identify the predominant environmental gradients driving divergence, identify the spatial scales at which gene flow and dispersal occur, and characterize how adaptive divergence is related to quantitative estimates of gene flow. We produced a dataset of 19,131 single nucleotide polymorphisms (SNPs) from 697 individuals, with an overall missing data percentage of 24.5. We found an average observed heterozygosity of 0.1826 range-wide, with a global genetic differentiation value of 0.1471. The best supported clustering solution was five clusters, similar to previous studies of genetic structure in this species, that corresponded to the north, east, south, west, and central Mojave Desert.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 2023
- Accession Number
- AD1227475
Entities
People
- Amy Vandergast
- Jill Heaton
- Kathy Simon
- Kenneth Nussear
- Rachel Woodward
- Scott Bassett
- Todd C. Esque
Organizations
- University of Nevada, Reno