Genetic evaulation of refuge populations of Desert Pupfish (Cyprinodon macularius)

Authors: Casandra Manuelitio, Thomas Turner, Megan Osborne

Year: 2024

Abstract

The desert pupfish, Cyprinodon macularius, was once widely distributed in low flow habitats throughout the Colorado River system. Loss of habitat, reduction in range and abundance resulted in C. macularius being listed as endangered. This species is now maintained in refuges to preserve genetic diversity and prevent extinction. Previous research identified significant divergence between populations in the Salton Sea and those in the Lower Colorado Delta. Results from previous evaluations of the diversity contained in refuge populations showed that across all populations diversity was maintained although genetic drift had caused divergence of allele frequencies among populations. Our study aimed to evaluate the current genetic status of C. macularius refuge populations using the same molecular markers (7 microsatellite loci) We estimated genetic diversity and effective population size in 13 refuge populations. Effective population size was variable among populations, with the lowest values recorded in the Pima refuge population and the highest Ne at Bill Williams and Little Joe Spring. Little Joe Spring also had the highest allelic and gene diversity. There was also evidence of genetic divergence among refuge populations. Preliminary results will be compared to previous findings.