Microsatellite primer development for the largespring gambusia, Gambusia geiseri

Authors: James C. II Cureton, Anna B. Buchman, Chris P. Randle, Raelynn Deaton

Year: 2008 (xl)

Abstract

The largespring gambusia, Gambusia geiseri, is a livebearing, spring-dwelling fish of the family Poeciliidae that is habitat sensitive and survives only in large, cool springs. In an attempt to reduce the mosquito populations many years ago, G. geiseri was mistakenly introduced into several rivers and springs all across Texas, resulting in several isolated populations. Deaton et al. (in prep) have shown significant genetic divergence at seven microsatellite loci across six populations of G. geiseri throughout Central and West Texas. However, they used microsatellite primers developed for G. affinis, which are not highly compatible with G. geiseri. Microsatellite primers are commonly developed and used to investigate multiple paternity questions as well as hybridization, genetic variation, and divergence across populations. Because they evolve quickly and have high polymorphism, they are desirable in genetic analyses. The purpose of this study is to develop microsatellite primers for G. geiseri that will be used to assess genetic variation and differentiation within and among several isolated populations of G. geiseri, to investigate multiple paternity across isolated populations, and to make primers specific to G. geiseri available to other researchers who are studying some aspect of G. geiseri biology. At this time, five primers have been optimized and are currently being tested on the San Marcos population of G. geiseri. Here, we will provide initial, basic analyses of current microsatellites in process of development, including the number of alleles, linkage disequilibrium among loci, observed & expected heterozygosity, and the inbreeding level.