A sex-chromosome inversion causes strong overdominance for sperm traits that affect siring success

0476722 - ÚBO 2018 RIV GB eng J - Journal Article
Knief, U. - Forstmeier, W. - Pei, Y. - Ihle, M. - Wang, D. - Martin, K. - Opatová, Pavlína - Albrechtová, Jana - Wittig, M. - Franke, A. - Albrecht, Tomáš - Kempenaers, B.
A sex-chromosome inversion causes strong overdominance for sperm traits that affect siring success.
Nature Ecology & Evolution. Roč. 1, č. 8 (2017), s. 1177-1184. ISSN 2397-334X. E-ISSN 2397-334X
R&D Projects: GA ČR(CZ) GAP506/12/2472
Institutional support: RVO:68081766
Keywords : Finch Taeniopygia guttata * mixed-effects models * zebra finch * pericentric inversions * fitness consequences * genetic parameters
OECD category: Biology (theoretical, mathematical, thermal, cryobiology, biological rhythm), Evolutionary biology

Male reproductive success depends on the competitive ability of sperm to fertilize the ova, which should lead to strong selection on sperm characteristics. This raises the question of how heritable variation in sperm traits is maintained. Here we show that in zebra finches (Taeniopygia guttata) nearly half of the variance in sperm morphology is explained by an inversion on the Z chromosome with a 40% allele frequency in the wild. The sperm of males that are heterozygous for the inversion had the longest midpieces and the highest velocity. Furthermore, such males achieved the highest fertility and the highest siring success, both within-pair and extra-pair. Males homozygous for the derived allele show detrimental sperm characteristics and the lowest siring success. Our results suggest heterozygote advantage as the mechanism that maintains the inversion polymorphism and hence variance in sperm design and in fitness.
Permanent Link: http://hdl.handle.net/11104/0273155