Dataset Information

A species delimitation approach in the Trochulus sericeus/hispidus complex reveals two cryptic species within a sharp contact zone.

ABSTRACT:

Background

Mitochondrial DNA sequencing increasingly results in the recognition of genetically divergent, but morphologically cryptic lineages. Species delimitation approaches that rely on multiple lines of evidence in areas of co-occurrence are particularly powerful to infer their specific status. We investigated the species boundaries of two cryptic lineages of the land snail genus Trochulus in a contact zone, using mitochondrial and nuclear DNA marker as well as shell morphometrics.

Results

Both mitochondrial lineages have a distinct geographical distribution with a small zone of co-occurrence. In the same area, we detected two nuclear genotype clusters, each being highly significantly associated to one mitochondrial lineage. This association however had exceptions: a small number of individuals in the contact zone showed intermediate genotypes (4%) or cytonuclear disequilibrium (12%). Both mitochondrial lineage and nuclear cluster were statistically significant predictors for the shell shape indicating morphological divergence. Nevertheless, the lineage morphospaces largely overlapped (low posterior classification success rate of 69% and 78%, respectively): the two lineages are truly cryptic.

Conclusion

The integrative approach using multiple lines of evidence supported the hypothesis that the investigated Trochulus lineages are reproductively isolated species. In the small contact area, however, the lineages hybridise to a limited extent. This detection of a hybrid zone adds an instance to the rare reported cases of hybridisation in land snails.

SUBMITTER: Depraz A

PROVIDER: S-EPMC2724411 | biostudies-literature | 2009 Jul

REPOSITORIES: biostudies-literature

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Publications

A species delimitation approach in the Trochulus sericeus/hispidus complex reveals two cryptic species within a sharp contact zone.

Dépraz Aline A Hausser Jacques J Pfenninger Markus M

BMC evolutionary biology 20090721

<h4>Background</h4>Mitochondrial DNA sequencing increasingly results in the recognition of genetically divergent, but morphologically cryptic lineages. Species delimitation approaches that rely on multiple lines of evidence in areas of co-occurrence are particularly powerful to infer their specific status. We investigated the species boundaries of two cryptic lineages of the land snail genus Trochulus in a contact zone, using mitochondrial and nuclear DNA marker as well as shell morphometrics.<h ...[more]

PMID: 19622149

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Project description:BackgroundOur ability to investigate processes shaping the evolutionary diversification of corals (Cnidaria: Anthozoa) is limited by a lack of understanding of species boundaries. Discerning species of corals has been challenging due to a multitude of factors, including homoplasious and plastic morphological characters and the use of molecular markers that are either not informative or have not completely sorted. Hybridization can also blur species boundaries by leading to incongruence between morphology and genetics. We used traditional DNA barcoding and restriction-site associated DNA sequencing combined with coalescence-based and allele-frequency methods to elucidate species boundaries and simultaneously examine the potential role of hybridization in a speciose genus of octocoral, Sinularia.ResultsSpecies delimitations using two widely used DNA barcode markers, mtMutS and 28S rDNA, were incongruent with one another and with the morphospecies identifications. When mtMutS and 28S were concatenated, a 0.3% genetic distance threshold delimited the majority of morphospecies. In contrast, 12 of the 15 examined morphospecies formed well-supported monophyletic clades in both concatenated RAxML phylogenies and SNAPP species trees of > 6000 RADSeq loci. DAPC and Structure analyses also supported morphospecies assignments, but indicated the potential for two additional cryptic species. Three morphologically distinct species pairs could not, however, be distinguished genetically. ABBA-BABA tests demonstrated significant admixture between some of those species, suggesting that hybridization may confound species delimitation in Sinularia.ConclusionsA genomic approach can help to guide species delimitation while simultaneously elucidating the processes generating coral diversity. Results support the hypothesis that hybridization is an important mechanism in the evolution of Anthozoa, including octocorals, and future research should examine the contribution of this mechanism in generating diversity across the coral tree of life.

Dataset Information

A species delimitation approach in the Trochulus sericeus/hispidus complex reveals two cryptic species within a sharp contact zone.

Background

Results

Conclusion

Publications

A species delimitation approach in the Trochulus sericeus/hispidus complex reveals two cryptic species within a sharp contact zone.

Similar Datasets

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