TY  - JOUR
A1  - Schmidt, Hanno
A1  - Tzovaras, Bastian Greshake
A1  - Feldmeyer, Barbara
A1  - Hankeln, Thomas
A1  - Pfenninger, Markus
T1  - Genomic basis of ecological niche divergence among cryptic sister species of non-biting midges
T2  - BMC genomics
N2  - 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.
KW  - Adaptive sequence evolution
KW  - Positive selection
KW  - McDonald-Kreitman test
KW  - Chironomus riparius
KW  - Chironomus piger
Y1  - 2013
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/31513
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-315130
SN  - 1471-2164
N1  - © 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.
VL  - 14
IS  - Art. 384
SP  - 1
EP  - 11
PB  - BioMed Central ; Springer
CY  - London ; Berlin ; Heidelberg
ER  -