10.5061/DRYAD.713Q3
Weber, Alexandra A. T.
Aix-Marseille University
Abi-Rached, Laurent
Aix-Marseille University
Galtier, Nicolas
École Pratique des Hautes Études
Bernard, Aurélien
École Pratique des Hautes Études
Montoya-Burgos, Juan I.
University of Geneva
Chenuil, Anne
Aix-Marseille University
Weber, A. A.-T.
Aix-Marseille University
University of Basel
Data from: Positive selection on sperm ion channels in a brooding brittle
star: consequence of life-history traits evolution
Dryad
dataset
2017
Ophioderma longicauda
Sperm chemotaxis
ion channel
Ophioderma
transcriptomes
Marine invertebrates
2017-01-17T14:24:52Z
2017-01-17T14:24:52Z
en
https://doi.org/10.1111/mec.14024
8478976 bytes
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CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Closely related species are key models to investigate mechanisms leading
to reproductive isolation and early stages of diversification, also at the
genomic level. The brittle star cryptic species complex Ophioderma
longicauda encompasses the sympatric broadcast spawning species C3 and the
internal brooding species C5. Here we used de novo transcriptome
sequencing and assembly in two closely related species displaying
contrasting reproductive modes to compare their genetic diversity and to
investigate the role of natural selection in reproductive isolation. We
reconstructed 20,146 and 22,123 genes for C3 and C5, respectively, and
characterized a set of 12,229 orthologs. Genetic diversity was 1.5-2 times
higher in C3 compared to C5, confirming that species with low parental
investment display higher levels of genetic diversity. Forty-eight genes
were the targets of positive diversifying selection during the evolution
of the two species. Notably, two genes (NHE and TetraKCNG) are
sperm-specific ion channels involved in sperm motility. Ancestral sequence
reconstructions show that natural selection targeted the two genes in the
brooding species. This may result from an adaptation to the novel
environmental conditions surrounding sperm in the brooding species, either
directly affecting sperm, or via an increase in male/female conflict. This
phenomenon could have promoted prezygotic reproductive isolation between
C3 and C5. Finally, the sperm receptors to egg chemoattractants differed
between C3 and C5 in the ligand-binding region. We propose that mechanisms
of species-specific gamete recognition in brittle stars occur during sperm
chemotaxis (sperm attraction towards the eggs), contrary to other marine
invertebrates where prezygotic barriers to interspecific hybridization
typically occur before sperm-egg fusion.
assembled_transcriptomesHere you will find the assembled transcriptomes
for the brittle star species Ophioderma longicauda C3 (broadcasting
species) and Ophioderma longicauda C5 (brooding species)alignmentsHere you
will find the alignments in fasta format of the 11 genes evolving under
positive selection (the ones listed in Table 3 of the article) and the
alignments for the genes involved in fertilization and species recognition
in other marine invertebrates (the ones listed in Table 4; e.g. bindin)
Atlantic Ocean
Mediterranean Sea