RHINOSPEC

Dissecting speciation using a genomics approach

 Partecipanti

Mappa

 Word cloud

Esplora la "nuvola delle parole (Word Cloud) per avere un'idea di massima del progetto.

 Obiettivo del progetto (Objective)

'Our proposal will tackle a central issue in biology: what is the genetic basis of species differentiation? Recent evidence of genetic exchange among species has led many to reject the traditional view that speciation requires complete reproductive isolation. Instead, the emerging new concept of so-called ‘genic speciation’ asserts that reproductive barriers can be established by divergence at only a few loci against a background of gene flow. We will combine novel and powerful analytical methods with new and traditional genetic technologies to investigate the genetic basis of species differences, and the process of divergence, in a model system of two co-distributed species of horseshoe bat (R. yunanensis and R. p. pearsoni). The Incoming Fellow has previously shown that, in these taxa, there is strong evidence of extensive past replacement of the nuclear genome in spite of clear phenotypic, acoustic and karyotypic differences. This unusual system provides an exceptional opportunity to identify and characterize genes that encode phenotypic differences among taxa, and also to determine the functional characteristics of ‘leaky genes’ versus ‘non-leaky genes’ (or ‘species genes’). Such knowledge of a natural mammalian system at a genome scale would take us beyond the current state-of-the art of research in this field, and would have impact in frontier science as well as potential benefits to conservation, genetics and evolutionary biologists. We will use Next Generation Sequencing and a highly novel statistical pipeline to identify key loci and larger ‘genomic islands’ that have resisted introgressive hybridization between our focal taxa. Our phylogenomic approach will then be extended to a larger sample to study whether these loci are under selection. Finally, we will apply chromosomal genetics methods to establish whether non-leaky loci and islands are influenced by the presence of chromosomal rearrangements, such as inversions.'

Introduzione (Teaser)

Genomic research into wild horseshoe bats has given fresh insight into formation of new species. Novel sequencing techniques can show which genes are driving reproductive isolation.

Descrizione progetto (Article)

Researchers in the 'Dissecting speciation using a genomics approach' (RHINOSPEC) project have compiled a massive amount of data on one aspect of species interaction, inbreeding or hybridisation. Using new next genome sequencing (NGS) methods, they have identified genes that have introgressed, that is, they are expressed in the hybrid bat. The assumption is that genes important for survival will introgress and show in the phenotype.

The study focused on co-distributed horseshoe bats in China, Rhinolophus pearsoni pearsoni (R. p. pearsoni), R. p. chinensis and R. yunanensis. Previous research has already indicated that introgression has occurred. The RHINOSPEC team determined to what extent this introgression had occurred.

Data from two new NGS protocols, transcriptome sequencing (RNAseq) and targeted resequencing, yielded around 10 000 genes per group to characterise. Out of the 3 655 genes that were studied, 134 genes were either putative introgression or speciation genes, that is, involved in reproductive isolation.

Identifying genes using a new RNA-based method has 'baited' 2 000 genes that have been resequenced. Eighty of these genes are involved in echolocation and the team will be able to test if this sensory method plays a part in reproductive isolation. A completely new study will focus on the importance of the X chromosome in speciation. Also, the significance of chromosome rearrangements in species mixing can be assessed.

Two papers have already featured in peer-reviewed journals and another five are anticipated. RHINOSPEC has collected a large amount of data for analysis on exactly how species mix and become separated in the wild. In particular, knowledge will increase on the relevance of interbreeding in natural populations.