Genetic variability and Inbreeding of the Sonoyta Pupfish Cyprinodon eremus Miller and Fuiman, 1987, in artificial refuges and wild populations of Sonora, Mexico

Authors: Román Rodríguez-Ramírez, Alejandro Varela-Romero, Nohelia Pacheco-Hoyos, José Grijalva-Chon, Marco López-Torres, Anthony Echelle

Year: 2019

Abstract

The Sonoyta Pupfish, Cyprinodon eremus, is an endemic species of the Sonoyta River basin (Sonora) and the Quitobaquito spring (Arizona). Its current distribution is restricted by anthropogenic impacts and does not have an official conservation status. As an immediate conservation strategy in response to the imminent removal of its population in Mexico, four artificial refuges was built in Sonora, however, its establishment was without considering genetic indicators of the population of origin. The hypothesis states indicators of genetic variability changes and inbreeding in artificial refuges were caused by isolation and genetic differentiation due to bottlenecks and founder effect. The objective is to evaluate their genetic variability and inbreeding level in three artificial refuges and the wild population in Sonora, by means of ten microsatelite loci and determine parameters of genetic variability, genetic equilibrium, fixation index (Rst and Fis) and presence of bottlenecks. The results indicate that there is a high genetic variability in all populations; the population of the Centro de Estudios de Desiertos y Océanos (CEDO) has the greatest genetic diversity. All refuge and wild populations have a genetic disequilibrium caused by heterozygous deficits. Fixation indices show little genetic differentiation (Rst = 0.007) and a high inbreeding coefficient (Fis = 0.26) indicating that there is divergence among all populations due to isolation. Presence of bottleneck was detected in the artificial refuge of the Centro Ecologico de Sonora (CES). In conclusion, only the population of the CEDO is potentially useful to increase the genetic variability of the rest of the refuges, since the indicators of genetic variability agree with those of the wild population, this population could be subject of source individuals for their reintroduction in the Sonoyta River in case it is required.