Differential gene expression in semispecies and hybrids of Drosophila paulistorum

• Gene expression divergence is correlated with and can be either a cause or a consequence of species divergence. Studying gene expression differences between closely related species, and their hybrid offspring, can thus give us clues about genes and mechanisms associated with reproductive isolation (RI) between them and allow us to better understand early stages of speciation. In this study, we use RNA-Seq to investigate gene expression divergence between the Amazonian, Centro-American and Orinocan semispecies of Drosophila paulistorum, a species cluster in statu nascendi, and between inter-semispecies hybrids and their parents. We uncover a large number of genes with varying expression between semispecies, with the highest numbers in male abdomens. The differentially expressed genes are associated with a range of biological functions, but especially with broad, regulatory functions, that are governed by transcription, translation, post-translational modifications and induced by signal transduction. We found that the expression pattern of hybrids was much more similar to the maternal line and that very few genes have a different expression than both of their parents. When comparing the differentially expressed genes in semispecies and hybrids to gene affected by Wolbachia in D. paulistorum, we see a small overlap. However, especially in hybrids, some of the overlapping genes appear to be highly relevant. Our study provides insights about expression differences associated with RI in D. paulistorum, and the impact of Wolbachia on the divergence of semispecies and hybrid sterility.

Ämnesord

NATURVETENSKAP  -- Biologi -- Evolutionsbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Evolutionary Biology (hsv//eng)

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