Document Type
Article
Publication Date
2022
Publication Title
Ecology and Evolution
Volume
12
Issue
7
Pages
1-10
Abstract
Loss and reduction in paired appendages are common in vertebrate evolution. How often does such convergent evolution depend on similar developmental and genetic pathways? For example, many populations of the threespine stickleback and ninespine stickleback (Gasterosteidae) have independently evolved pelvic reduction, usually based on independent mutations that caused reduced Pitx1 expression. Reduced Pitx1 expression has also been implicated in pelvic reduction in manatees. Thus, hindlimb reduction stemming from reduced Pitx1 expression has arisen independently in groups that diverged tens to hundreds of millions of years ago, suggesting a potential for repeated use of Pitx1 across vertebrates. Notably, hindlimb reduction based on the reduction in Pitx1 expression produces left-larger directional asymmetry in the vestiges. We used this phenotypic signature as a genetic proxy, testing for hindlimb directional asymmetry in six genera of squamate reptiles that independently evolved hindlimb reduction and for which genetic and developmental tools are not yet developed: Agamodon anguliceps, Bachia intermedia, Chalcides sepsoides, Indotyphlops braminus, Ophisaurus attenuatuas and O. ventralis, and Teius teyou. Significant asymmetry occurred in one taxon, Chalcides sepsoides, whose left-side pelvis and femur vestiges were 18% and 64% larger than right-side vestiges, respectively, suggesting modification in Pitx1 expression in that species. However, there was either right-larger asymmetry or no directional asymmetry in the other five taxa, suggesting multiple developmental genetic pathways to hindlimb reduction in squamates and the vertebrates more generally.
Recommended Citation
Swank, Samantha; Elazegui, Ethan; Janidlo, Sophia; Sanger, Thomas J.; Bell, Michael A.; and Stuart, Yoel E.. Attempting Genetic Inference from Directional Asymmetry during Convergent Hindlimb Reduction in Squamates. Ecology and Evolution, 12, 7: 1-10, 2022. Retrieved from Loyola eCommons, Biology: Faculty Publications and Other Works, http://dx.doi.org/10.1002/ece3.9088
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This work is licensed under a Creative Commons Attribution 4.0 International License.
Copyright Statement
© 2022 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.
Comments
© 2022 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.
https://doi.org/10.1002/ece3.9088