Dramatic shifts in the gene pool of a managed population of an endangered species may be exacerbated by high genetic load

作者：Martin Andrew P^*; Echelle Anthony A; Zegers Gerard; Baker Sherri; Keeler Foster Connie L

来源：Conservation Genetics, 2012, 13(2): 349-358.

DOI：10.1007/s10592-011-0289-7

• Small populations
• Genetic load
• Endangered species
• Pupfish
• Microsatellites

The Devils Hole pupfish, Cyprinodon diabolis, is restricted to a small habitat in southwestern Nevada. In 1972 the species was federally listed as an endangered species. Management efforts to mitigate extinction risks have been plagued by the inability to propagate the species in aquaria-anomalous for the genus-and repeated failure of propagation attempts in large, outdoor, artificial pools designed to mimic natural conditions in Devils Hole. These difficulties indicate that the species either has niche requirements that are not adequately recreated under artificial conditions or that it harbors a relatively large genetic load of deleterious mutations that compromises propagation. We used variation at 12 microsatellite loci to evaluate the results of natural, uncontrolled hybridization involving a population of C. diabolis inhabiting an artificial pool and invaders from a nearby population of the closely related C. nevadensis. The results suggest that following invasion of the pool by three C. nevadensis individuals, the gene pool underwent a rapid shift from pure C. diabolis to one comprised mostly of C. nevadensis alleles. Alleles diagnostic for C. nevadensis increased from about 0.03 to an average of 0.76 across four diagnostic loci over the course of 8 years or less. Although we cannot exclude explanations based on adaptation to Devils Hole, genetic drift, or demographic variability, these results and various other aspects of the biology of C. diabolis are best explained by the genetic load hypothesis. The work suggest avenues for future experimental work to evaluate these possibilities directly and provide an explanation for why some previous propagation efforts designed to mitigate extinction risk have failed.

• 出版日期2012-4