Beyond the point of no return? A comparison of genetic diversity in captive and wild populations of two nearly extinct species of Goodeid fish reveals that one is inbred in the wild

Abstract

The relative importance of genetic and non-genetic factors in extinction liability has been extensively debated. Here, we examine the levels of genetic variability at 13 (seven informative) loci in wild and captive populations of two endangered species of Mexican Goodeid fish, Ameca splendens and Zoogoneticus tequila. Allelic diversity was higher in the wild populations, and F IS lower. Values of y ( ¼ 4Nem) were estimated using a coalescent approach. These implied that the effective population size of all captive populations of A. splendens were smaller than that of the wild population; qualitatively similar results were obtained using an analytical method based on within-population gene identity disequilibrium. However, the wild population of Z. tequila did not show a significantly greater estimate of y. We used the Beaumont approach to infer population declines, and found that both species showed clear evidence of a decline in effective population size, although this was stronger and probably occurred over a longer period of time in Z. tequila than in A. splendens. The decline in Z. tequila probably occurred before captive populations were established. We discuss implications for the conservation of critically endangered populations.

Patterns of ancestry and genetic diversity in reintroduced populations of the slimy sculpin: implications for conservation

“…They are limited by sparse thermal habitat in the small reaches of stream near cold perennial groundwater inputs. As a result, these populations are isolated from other populations making them potentially susceptible to local extinction through risks, such as catastrophic events or inbreeding depression as demonstrated in other animal populations (Saccheri et al 1998;Bailey et al 2007). Anthropogenically triggered shifts in hydrologic regimes could cause slimy sculpins, which require a constant source of cold water, to disappear or struggle to survive at the peripheries of their range where thermal clines are of great consequence (Meisner 1990a;Magnuson and Destasio 1997).…”

Changes in diet, growth and survivorship of the native Tequila Splitfin Zoogoneticus tequila in co-occurrence with the non-native Shortfin Molly Poecilia mexicana

“…Unfortunately, there is no information regarding the tolerance of goodeids to environmental factors, but the high vulnerability of many goodeid species (e.g. Domínguez-Domínguez et al 2005;Bailey et al 2007) suggests a low tolerance to habitat changes. Despite the potential differences in altitude between the experimental ponds (1900 m a.s.l.)…”

“…The Mexican Ecological Norm (NOM-ECOL-059 -2010) and the IUCN Red List of Threatened Species consider Z. tequila to be endangered and critically endangered, respectively. Populations of Z. tequila have been dramatically reduced since 1990 (Webb & Miller 1998), and more recently a small population (less than 500 individuals) was found in the headwaters of the Teuchitlán River (De La Vega-Salazar et al 2003a;De La Vega-Salazar et al 2003b;Bailey et al 2007). The causes of this population decrease in the wild is uncertain, but the most commonly suggested hypothesis involves a combination of the introduction of non-native species, pollution, deforestation, water extraction and habitat fragmentation in the Ameca River (Webb & Miller 1998;De La Vega-Salazar et al 2003a;Domínguez-Domínguez et al 2006;Domínguez-Domínguez et al 2007).…”

La diversidad sexo-genérica: Un punto de vista evolutivo

“…Hay una gran cantidad de ejemplos de tales diferencias de sexo y de género en el reino animal. [12][13][14][15] Una mosca de la fruta, por ejemplo, puede cortejar a otros machos porque carece de un gen que le permite establecer la diferencia entre los sexos. Pero eso es muy diferente a los delfines de nariz de botella machos, que se dedican a las interacciones entre individuos del mismo género para facilitar la unión de grupo, o el albatros de Laysan femeninos, que pueden permanecer consolidados de por vida y desarrollan funciones cooperativas en la crianza de los polluelos.…”