Parasite Resistance in Gila and Yaqui Topminnows

赫德里克9807490濒危物种面临着许多威胁，包括栖息地的丧失，非本地捕食者和狩猎。导致濒危物种减少的主要因素之一是寄生虫（广义上定义为病毒，细菌和其他传染性病原体）。当一个濒危物种减少到边缘栖息地，失去了遗传变异，或者从小种群或孤立种群变成近亲繁殖时，寄生虫可能会产生更大的影响。在这里，我们研究的影响，非本地的寄生虫对濒危的希拉和Yaqui topminnows。Gila topminnow仅在亚利桑那州的9个本地地点发现，Yaqui topminnow仅在亚利桑那州东南部的San Bernadino野生动物保护区发现。在遗传学和生态学上，吉拉托普米诺鱼一直是广泛研究的对象。特别是，在主要组织相容性复合体（MHC）基因座的变化，被认为是参与寄生虫在所有脊椎动物的免疫力的基因，已被表征。 在这项研究中，我们将研究这些topminows的不同人群是否有不同的阻力，非本地寄生吸虫，以及是否差异相关的MHC基因座的变化。此外，我们将研究是否近交系鱼有不同的易感性比非近交系鱼的寄生虫。通过这种方式，我们将能够确定影响这种濒危物种中寄生虫抗性的遗传机制，生成用于检查濒危物种中这种威胁的模型，并直接解决这两种濒危物种中的潜在问题。

Hedrick 9807490 Endangered species face many threats including loss of habitat, non-native predators, and hunting. One of the major factors causing the reduction of endangered species are parasites (defined broadly as viruses, bacteria, and other infectious agents). Parasites may have a greater impact when an endangered species is reduced to marginal habitat, has lost genetic variation, or becomes inbred from having small or isolated populations. Here we examine the impact of a non-native parasite on the endangered Gila and Yaqui topminnows. The Gila topminnow is found only in nine native locations in Arizona and the Yaqui topminnow only on the San Bernadino Wildlife Refuge in southeastern Arizona. The Gila topminnow has been the subject of extensive examination both genetically and ecologically. In particular, variation at a major histocompatibility complex (MHC) locus, genes thought to be involved in parasite resisitance in all vertebrates, has been characterized. In this research we will examine whether different populations of the these topminows have different resistance to a non-native parasitic fluke and whether differences are related to variation in the MHC locus. In addition we will examine whether inbred fish have a different susceptibility to the parasite than non-inbred fish. In this way we will be able to determine the genetic mechanisms influencing parasite resistance in this endangered species, generate a model for examining such threats in endangered species and directly address potential treats in these two endangered species.