Fitness consequences of polymorphic inversions in the zebra finch genome

Ulrich Knief*, Georg Hemmrich-Stanisak, Michael Wittig, Andre Franke, Simon C. Griffith, Bart Kempenaers, Wolfgang Forstmeier

*Corresponding author for this work

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19 Citations (Scopus)
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Abstract

Background: Inversion polymorphisms constitute an evolutionary puzzle: they should increase embryo mortality in heterokaryotypic individuals but still they are widespread in some taxa. Some insect species have evolved mechanisms to reduce the cost of embryo mortality but humans have not. In birds, a detailed analysis is missing although intraspecific inversion polymorphisms are regarded as common. In Australian zebra finches (Taeniopygia guttata), two polymorphic inversions are known cytogenetically and we set out to detect these two and potentially additional inversions using genomic tools and study their effects on embryo mortality and other fitness-related and morphological traits. Results: Using whole-genome SNP data, we screened 948 wild zebra finches for polymorphic inversions and describe four large (12-63 Mb) intraspecific inversion polymorphisms with allele frequencies close to 50 %. Using additional data from 5229 birds and 9764 eggs from wild and three captive zebra finch populations, we show that only the largest inversions increase embryo mortality in heterokaryotypic males, with surprisingly small effect sizes. We test for a heterozygote advantage on other fitness components but find no evidence for heterosis for any of the inversions. Yet, we find strong additive effects on several morphological traits. Conclusions: The mechanism that has carried the derived inversion haplotypes to such high allele frequencies remains elusive. It appears that selection has effectively minimized the costs associated with inversions in zebra finches. The highly skewed distribution of recombination events towards the chromosome ends in zebra finches and other estrildid species may function to minimize crossovers in the inverted regions.

Original languageEnglish
Article number199
Pages (from-to)1-22
Number of pages22
JournalGenome Biology
Volume17
DOIs
Publication statusPublished - 29 Sep 2016

Bibliographical note

Copyright the Author(s) 2016. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

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    Knief, U., Hemmrich-Stanisak, G., Wittig, M., Franke, A., Griffith, S. C., Kempenaers, B., & Forstmeier, W. (2016). Fitness consequences of polymorphic inversions in the zebra finch genome. Genome Biology, 17, 1-22. [199]. https://doi.org/10.1186/s13059-016-1056-3