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Influencia diferencial de la expresión de Slc7a11 y la condición corporal sobre la pigmentación producida por feomelanina en dos poblaciones de trepador azul Sitta europea con diferente riesgo de depredación

The expression of the gene Slc7a11 promotes the antioxidant capacity of cells by providing them with cysteine that can be used for the synthesis of glutathione (GSH), the most important intracellular antioxidant. In melanocytes, intracellular cysteine can also enter melanosomes and get incorporated in the pigment pheomelanin synthesis pathway, thus decreasing cysteine availability for GSH synthesis and potentially creating chronic oxidative stress. Therefore, this study hypothesized that a mechanism limiting the use of intramelanocytic cysteine for pheomelanin synthesis in environmental conditions generating oxidative stress may be physiologically advantageous and favored by natural selection. Evidence we searched of such a mechanism by comparing the influence of melanocytic Slc7a11 expression on pheomelanin?based pigmentation in developing Eurasian nuthatch Sitta europaea nestlings from two populations differing in predation risk, a natural source of oxidative stress. Pheomelanin synthesis and pigmentation tended to increase with Slc7a11 expression in the low?risk population as expected from the activity of this gene, but decreased with Slc7a11 expression in the high?risk population. The same was not observed in the expression of five other genes influencing pheomelanin synthesis without affecting cysteine availability in melanocytes. The influence of body condition on the intensity of pheomelanin?based pigmentation also differed between populations, being positive in the low?risk population and negative in the high?risk population. The resulting pigmentation of birds was more intense in the high?risk population. These findings suggest that birds perceiving high predation risk may limit the use of cysteine for pheomelanin synthesis, which becomes independent of Slc7a11 expression. Some birds may have thus evolved the ability to adjust their pigmentation phenotype to environmental stress. informacion[at]ebd.csic.es: Galván & Sanz (2020) Differential influence of Slc7a11 expression and body condition on pheomelanin-based pigmentation in two Eurasian nuthatch Sitta europaea populations with different predation risk. J Avian Biol DOI 10.1111/jav.02275


https://onlinelibrary.wiley.com/doi/10.1111/jav.02275
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Genetic evaluation of the Iberian lynx ex situ conservation programme

Genetic evaluation of the Iberian lynx ex situ conservation programme

Ex situ programmes have become critical for improving the conservation of many threatened species, as they establish backup populations and provide individuals for reintroduction and reinforcement of wild populations. The Iberian lynx was considered the most threatened felid species in the world in the wake of a dramatic decline during the second half of the 20th century that reduced its numbers to around only 100 individuals. An ex situ conservation programme was established in 2003 with individuals from the two well-differentiated, remnant populations, with great success from a demographic point of view. This study evaluates the genetic status of the Iberian lynx captive population based on molecular data from 36 microsatellites, including patterns of relatedness and representativeness of the two remnant genetic backgrounds among founders, the evolution of diversity and inbreeding over the years, and genetic differentiation among breeding facilities. In general terms, the ex situ population harbours most of the genetic variability found in the two wild populations and has been able to maintain reasonably low levels of inbreeding and high diversity, thus validating the applied management measures and potentially representing a model for other species in need of conservation. The Iberian lynx ex situ breeding programme has been a key piece in the multifaceted conservation of the Iberian lynx. After 12 years, it has accomplished the two main goals that were set at the start. Firstly, it has succeeded in establishing a demographically and genetically healthy ex situ population that may act as a safeguard for the species in case of extinction in the wild. Secondly, after a few years of internal growth, the population has been serving as the almost exclusive source of individuals for reintroduction in the wild. Besides, the programme has assembled a set of experts in many different fields as well as fostered and coordinated research on issues of high relevance for the conservation of the species, while becoming a major driver of awareness and dissemination. The Iberian lynx ex situ programme has been quite effective in representing, boosting and maintaining the low genetic diversity that survived the latest severe bottleneck of the species while minimising the accumulation of inbreeding, which should ultimately result in increased adaptive potential and average fitness. In this regard, the Iberian lynx ex situ programme could serve as an example of marker-assisted pedigree-based management for other species at similar conservation stages. informacion[at]ebd.csic.es: Kleinman-Ruiz et al (2019) Genetic evaluation of the Iberian lynx ex situ conservation programme. Heredity Doi 10.1038/s41437-019-0217-z


https://www.nature.com/articles/s41437-019-0217-z