Fig. 6
From: Evidence against tetrapod-wide digit identities and for a limited frame shift in bird wings
Digits D2, D3, and D4 of the chicken forelimb correspond to D1, D3, and D4 of other limbs. This pattern is observed by a HCA and PCA of CDEGs for digits of chicken wing and hindlimb. b Expression levels of individual transcription factor genes in chicken. c In situ hybridization of alligator embryos confirms that the position of differential expression of transcription factors can be conserved between fore- and hindlimbs that differ in digit number. Arrowheads indicate distal-most expression along a developing digit. d Projection of chicken digit data upon PCA of CDEGs for mouse, alligator, and Anolis. TPM values shown in panels b and c calculated from the gene list of one-to-one orthologous genes between mouse, alligator, Anolis, chicken, and human. Source data for panel c are provided as a Source Data file. Alligator and chicken illustrations reproduced with permission by Michael Richardson. Anolis illustration by Sarah Werning without modification (license [https://creativecommons.org/licenses/by/3.0/])
