Genomic basis of ecological niche divergence among cryptic sister species of non-biting midges

Background: There is a lack of understanding the evolutionary forces driving niche segregation of closely related organisms. In addition, pinpointing the genes driving ecological divergence is a key goal in molecular eco
Background: There is a lack of understanding the evolutionary forces driving niche segregation of closely related organisms. In addition, pinpointing the genes driving ecological divergence is a key goal in molecular ecology. Here, larval transcriptome sequences obtained by next-generation-sequencing are used to address these issues in a morphologically cryptic sister species pair of non-biting midges (Chironomus riparius and C. piger).
Results: More than eight thousand orthologous open reading frames were screened for interspecific divergence and intraspecific polymorphisms. Despite a small mean sequence divergence of 1.53% between the sister species, 25.1% of 18,115 observed amino acid substitutions were inferred by α statistics to be driven by positive selection. Applying McDonald-Kreitman tests to 715 alignments of gene orthologues identified eleven (1.5%) genes driven by positive selection.
Conclusions: Three candidate genes were identified as potentially responsible for the observed niche segregation concerning nitrite concentration, habitat temperature and water conductivity. Additionally, signs of positive selection in the hydrogen sulfide detoxification pathway were detected, providing a new plausible hypothesis for the species’ ecological differentiation. Finally, a divergently selected, nuclear encoded mitochondrial ribosomal protein may contribute to reproductive isolation due to cytonuclear coevolution.
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Author:Hanno Schmidt, Bastian Greshake Tzovaras, Barbara Feldmeyer, Thomas Hankeln, Markus Pfenninger
URN:urn:nbn:de:hebis:30:3-315130
DOI:http://dx.doi.org/10.1186/1471-2164-14-384
ISSN:1471-2164
Pubmed Id:http://www.ncbi.nlm.nih.gov/pubmed?term=23758757
Parent Title (English):BMC genomics
Publisher:BioMed Central ; Springer
Place of publication:London ; Berlin ; Heidelberg
Document Type:Article
Language:English
Date of Publication (online):2013/08/23
Date of first Publication:2013/06/10
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2013/08/23
Tag:Adaptive sequence evolution; Chironomus piger; Chironomus riparius; McDonald-Kreitman test; Positive selection
Volume:14
Issue:Art. 384
Pagenumber:11
First Page:1
Last Page:11
Note:
© 2013 Schmidt et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
HeBIS PPN:352731958
Institutes:Biowissenschaften
Senckenbergische Naturforschende Gesellschaft
Institut für Ökologie, Evolution und Diversität
Biodiversität und Klima Forschungszentrum (BiK-F)
Dewey Decimal Classification:590 Tiere (Zoologie)
Sammlungen:Universitätspublikationen
Licence (German):License LogoCreative Commons - Namensnennung 2.0

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