Genetic Analysis of Hybridization between Mohave tui chub and arroyo chub

Authors: Rachel C. Williams, Yongjiu Chen, Steve Parmenter, Debra L. Hughson, Frank Pezold

Year: 2010 (xlii)

Abstract

Mohave tui chub, Siphateles bicolor mohavensis, are no longer present in their native habitat of the Mojave River basin, California. The reintroduction and recovery of this endangered species is mandated by the U. S. Endangered Species Act, however, reintroduction has been hindered by the presence of non-native arroyo chub, Gila orcutti, in the river. The mass hybridization between S. b. mohavensis and G. orcutti is thought to have been the primary cause of S. b. mohavensis decline. Hybrids have never before been genetically identified and their genetic recombination is therefore unknown. This study aims to characterise the hybridization between the two species under experimental conditions, including 30 laboratory tanks and an outdoor pond. Samples of S. b. mohavensis and G. orcutti have been characterized; genome-wide single nucleotide polymorphism (SNP) and microsatellite DNA markers have been developed, allowing identification of both species and their hybrid offspring. The genetic composition of F1 offspring obtained from the outdoor pond experiment has also been investigated, yet no hybrids have thus far been detected. The tank hybridization experiments are currently in progress from which hybrids have been produced.