Approximately twenty years have passed since the beginning of concentrated investigations into the evolutionary history and ecology of skates. The evidence generated thus far suggests that skates have experienced multiple and parallel adaptive radiations at a regional scale, starting in the upper Cretaceous, which contributed to the delineation of strong phylo-geographical and population structuring. Despite the high species diversity characterising the Order Rajiformes, a strikingly stable gross morphology has been maintained on the evolutionary level. The combined use of morphometric analyses and genotyping by various panels of molecular markers on a large number of samples of widely distributed and endemic geographic populations provided efficient tools for stock identification and management. Nonetheless, the adaptive value of some phenotypic traits as, for instance, particular ornaments of the dorsal part of the body, remains poorly understood. Here, we applied transcriptome profiling of skin pictorial motifs (eyespots and dots on a uniformly coloured matrix) on recently diverged species with sibling and sister phylogenetic relationships (Raja clavata, R. straeleni and R. asterias respectively) and on species that are easily recognized by specific patterning traits and show strong monophyly (the Mediterranean R. miraletus and the South African R. ocellifera). The on-going differential expression analysis at skin transcriptome level will help to understand mechanisms of divergence, hybridisation signals and could be considered one of the tiles allowing to evaluate whether the same or alternative traits have been used in parallel adaptations to similar environments.
Species diversity and morphological stasis in skates (order Rajiformes): The challenge of skin transcriptome profiling in non-model species
FERRARI, ALICE;CARIANI, ALESSIA;TINTI, FAUSTO;
2016
Abstract
Approximately twenty years have passed since the beginning of concentrated investigations into the evolutionary history and ecology of skates. The evidence generated thus far suggests that skates have experienced multiple and parallel adaptive radiations at a regional scale, starting in the upper Cretaceous, which contributed to the delineation of strong phylo-geographical and population structuring. Despite the high species diversity characterising the Order Rajiformes, a strikingly stable gross morphology has been maintained on the evolutionary level. The combined use of morphometric analyses and genotyping by various panels of molecular markers on a large number of samples of widely distributed and endemic geographic populations provided efficient tools for stock identification and management. Nonetheless, the adaptive value of some phenotypic traits as, for instance, particular ornaments of the dorsal part of the body, remains poorly understood. Here, we applied transcriptome profiling of skin pictorial motifs (eyespots and dots on a uniformly coloured matrix) on recently diverged species with sibling and sister phylogenetic relationships (Raja clavata, R. straeleni and R. asterias respectively) and on species that are easily recognized by specific patterning traits and show strong monophyly (the Mediterranean R. miraletus and the South African R. ocellifera). The on-going differential expression analysis at skin transcriptome level will help to understand mechanisms of divergence, hybridisation signals and could be considered one of the tiles allowing to evaluate whether the same or alternative traits have been used in parallel adaptations to similar environments.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
