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Evidence against tetrapod-wide digit identities and for a limited frame shift in bird wings.

ABSTRACT: In crown group tetrapods, individual digits are homologized in relation to a pentadactyl ground plan. However, testing hypotheses of digit homology is challenging because it is unclear whether digits represent distinct and conserved gene regulatory states. Here we show dramatic evolutionary dynamism in the gene expression profiles of digits, challenging the notion that five digits have conserved developmental identities across amniotes. Transcriptomics shows diversity in the patterns of gene expression differentiation of digits, although the anterior-most digit of the pentadactyl limb has a unique, conserved expression profile. Further, we identify a core set of transcription factors that are differentially expressed among the digits of amniote limbs; their spatial expression domains, however, vary between species. In light of these results, we reevaluate the frame shift hypothesis of avian wing evolution and conclude only the identity of the anterior-most digit has shifted position, suggesting a 1,3,4 digit identity in the bird wing.

SUBMITTER: Stewart TA

PROVIDER: S-EPMC6642197 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature

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Evidence against tetrapod-wide digit identities and for a limited frame shift in bird wings.

Stewart Thomas A TA Liang Cong C Cotney Justin L JL Noonan James P JP Sanger Thomas J TJ Wagner Günter P GP

Nature communications 20190719 1

In crown group tetrapods, individual digits are homologized in relation to a pentadactyl ground plan. However, testing hypotheses of digit homology is challenging because it is unclear whether digits represent distinct and conserved gene regulatory states. Here we show dramatic evolutionary dynamism in the gene expression profiles of digits, challenging the notion that five digits have conserved developmental identities across amniotes. Transcriptomics shows diversity in the patterns of gene exp ...[more]

PMID: 31324809

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Dataset Information

Evidence against tetrapod-wide digit identities and for a limited frame shift in bird wings.

Publications

Evidence against tetrapod-wide digit identities and for a limited frame shift in bird wings.

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