Hybridization and genetic introgression following the introduction of exotic species can pose a significant threat to the survival of geographically restricted species. A remnant population of the critically endangered freshwater crayfish Cherax tenuimanus in the upper reaches of the Margaret River in southwestern Australia is under threat following the introduction and spread of its congener Cherax cainii. Here, we examine the extent of hybridization and introgression between the two species using twelve polymorphic microsatellite loci. Our study reveals there are three times more C. cainii than C. tenuimanus at our study site in the upper reaches of the Margaret River. There is also evidence of hybridization and introgression between C. tenuimanus and C. cainii at this site, with F1, F2 and backcrossed individuals identified. While interbreeding was confirmed in this study, our simulations suggest that the levels of introgression are much lower than would be expected under random mating, indicating partial reproductive barriers exist. Nevertheless, it is apparent that hybridization and introgression with C. cainii pose a serious threat to C. tenuimanus and their survival in the wild will require active adaptive management and continued genetic monitoring to evaluate management effectiveness.
The B family of Eph receptor tyrosine kinases and their ephrin ligands, best known for their role in the development of the nervous and vascular systems, have recently been implicated in mammalian kidney development and maintenance. However, the renal expression and function of the EphA and ephrin-A families have not been investigated. We performed immunohistochemistry for ephrin-A2 and ephrin-A5 in kidneys of normal adult wildtype (WT) mice and carried out quantitative morphological analysis of renal corpuscles and tubules in haematoxylin- and eosin-stained sections of WT, ephrin-A2-/-, ephrin-A5-/- and ephrin-A2A5-/- (knockout) mice. Ephrin-A2 and ephrin-A5 were strongly expressed in the tubules and glomeruli of the adult mouse kidney. Despite the significant overlap in expression between the two proteins, only the lack of ephrin-A5 had an effect on kidney morphology with glomerular size being mildly reduced in mice lacking the gene for ephrin-A5. However, the magnitude of this change was very small and could only be detected when animals were pooled across genotypes lacking ephrin-A5. The subtle phenotype, together with the relatively infrequent incidence of kidney failure in our breeding colony, suggest that ephrin-A2 and ephrin-A5 play only minor roles in kidney development and function. It is likely that other members of the ephrin-A family are expressed in the mouse kidney and redundancy within this large family of “promiscuous” signalling molecules may compensate for the loss of individual proteins in knockout mice.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.