We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
Shaping species with ephemeral boundaries: the distribution and genetic structure of desert tortoise ( Gopherus morafkai) in the Sonoran Desert region.
- Authors
Edwards, Taylor; Vaughn, Mercy; Rosen, Philip C.; Meléndez Torres, Cristina; Karl, Alice E.; Culver, Melanie; Murphy, Robert W.
- Abstract
Aim We examine the role biogeographical features played in the evolution of Morafka's desert tortoise ( Gopherus morafkai) and test the hypothesis that G. morafkai maintains genetically distinct lineages associated with different Sonoran Desert biomes. Increased knowledge of the past and present distribution of the Sonoran Desert region's biota provides insight into the forces that drive and maintain its biodiversity. Location Sonoran Desert biogeographical region; Sonora and Sinaloa, Mexico and Arizona, USA. Methods We examined wild tortoises from Mexico ( n = 155) and Arizona ( n = 78), spanning their known distribution. We used mt DNA sequences to reconstruct matrilineal relationships and 25 microsatellite ( STR) loci for Bayesian analyses of gene flow. We performed clinal analyses on both mt DNA and STR loci to determine the position and amount of introgression where lineages co-occur. We used GIS to assess the association of genetic structuring with ecological features. We used these data in a hypothesis-driven approach to assess different models of how genetic diversity is maintained and distributed in G. morafkai. Results Gopherus morafkai was found to comprise genetically and geographically distinct 'Sonoran' and 'Sinaloan' lineages. Both lineages occurred in a relatively narrow zone of overlap in Sinaloan thornscrub, where it transitions into Sonoran desertscrub. Limited introgression occurred at the contact zone. The best-fit model suggests that these lineages diverged in parapatry where the distribution of genotypes is environment-dependent and introgression is inhibited by exogenous selection. Main conclusions The historically shifting ecotone between tropical deciduous forest and Sonoran desertscrub appears to be a boundary that fostered divergence between parapatric lineages of tortoises. The sharp genetic cline between the two lineages suggests that periods of isolation in temporary refugia due to Pleistocene climatic cycling influenced divergence. Despite incomplete reproductive isolation, the Sonoran and Sinaloan lineages of G. morafkai are on separate evolutionary trajectories.
- Subjects
SONORAN Desert; MEXICO; SONORAN desert tortoise; DESERT ecology; DESERT tortoise; MITOCHONDRIAL DNA; TESTUDINIDAE; PLANTS
- Publication
Journal of Biogeography, 2016, Vol 43, Issue 3, p484
- ISSN
0305-0270
- Publication type
Article
- DOI
10.1111/jbi.12664