ausblenden:
Schlagwörter:
-
Zusammenfassung:
Poecilia reticulata (the guppy) has long been used as a model in evolutionary biology and ecology. While poecilids display many diverse sex-determining mechanisms, the guppy in particular displays male heterogamety and overt sexual dimorphism, which reflects some of its adaptations as a livebearer, for example, larger size and camouflage in females in contrast to the highly variable ornamental traits in smaller males. Variation and habitat-specific adaptation of male patterns are thought to evolve in the wild by interplay of sexual selection by mates and natural selection by predators. These polymorphic traits set a paradigm for inheritance of male advantageous genes that may have played important roles in sex chromosome evolution. Previously our laboratory has generated a dense linkage map of the guppy; however, no molecular markers are available for the highly heterochromatic male-specific region of the Y chromosome, as yet. To circumvent some problems of highly repetitive sequence for genomic walks or genome assembly using short NGS reads, we first perform sex-specific deep transcriptome sequencing with embryos and adults. We compare efficiency and fidelity of de novo assembly by Velvet, Multiple-k, STM and Oases and scrutinize the resulting transcriptomes for male-specific transcripts. These sex-specific expression profiles in complement to ongoing WGS experiments will facilitate identification of Y-linked ornamental genes and the Sex Determining Locus on the Y-chromosome. A comprehensive knowledge of the guppy exome is also useful for predicting gene models, and markers linked to expressed genes will enhance knowledge of regions under selection pressure in the wild.
