Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

A molecular shift in limb identity underlies the convergent evolution and development of feathered feet

ABSTRACT: The genetic and developmental mechanisms that control the decision between scale and feather growth â two profoundly different epidermal appendages, and an important developmental shift in the evolution of birds from their dinosaurian ancestors â remain poorly understood. Domestic pigeons display dramatic variation in foot epidermal appendages within a single species, and classical studies suggest that a small number of genes control much of this variation; thus pigeons provide a tractable model to understand skin appendage specification and variation. Here we show that feathered feet in pigeons are the consequence of a partial transformation of limb-type identity mediated by cis-regulatory changes in the hindlimb-specific transcription factor Pitx1 and forelimb-specific transcription factor Tbx5. We also demonstrate that ectopic hindlimb expression of Tbx5 is associated with the development of foot feathers in domestic chickens, suggesting that similar developmental mechanisms underlie phenotypic convergence in avian lineages that diverged over 100 MYA. These results show how qualitative and quantitative changes in expression of regional patterning genes can generate localized changes in organ fate and morphology, and provide a viable molecular mechanism for the evolution of hindlimb scale and feather distribution in dromaeosaurs. Examination of H3K27ac status in embryonic limb buds from two domestic pigeon breeds, racing homer and Indian fantail

ORGANISM(S): Columba livia

SUBMITTER: Michael Shapiro

PROVIDER: E-GEOD-67875 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Molecular shifts in limb identity underlie development of feathered feet in two domestic avian species.

Domyan Eric T ET Kronenberg Zev Z Infante Carlos R CR Vickrey Anna I AI Stringham Sydney A SA Bruders Rebecca R Guernsey Michael W MW Park Sungdae S Payne Jason J Beckstead Robert B RB Kardon Gabrielle G Menke Douglas B DB Yandell Mark M Shapiro Michael D MD

eLife 20160315

Birds display remarkable diversity in the distribution and morphology of scales and feathers on their feet, yet the genetic and developmental mechanisms governing this diversity remain unknown. Domestic pigeons have striking variation in foot feathering within a single species, providing a tractable model to investigate the molecular basis of skin appendage differences. We found that feathered feet in pigeons result from a partial transformation from hindlimb to forelimb identity mediated by cis ...[more]

PMID: 26977633

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Project description:The analysis of differentially expressed genes is a powerful approach to elucidate the genetic mechanisms underlying the morphological and evolutionary diversity among serially homologous structures, both within the same organism (e.g., hand vs. foot) and between different species (e.g., hand vs. wing). In the developing embryo, limb-specific expression of Pitx1, Tbx4, and Tbx5 regulates the determination of limb identity. However, numerous lines of evidence, including the fact that these three genes encode transcription factors, indicate that additional genes are involved in the Pitx1-Tbx hierarchy. To examine the molecular distinctions coded for by these factors, and to identify novel genes involved in the determination of limb identity, we have used Serial Analysis of Gene Expression (SAGE) to generate comprehensive gene expression profiles from intact, developing mouse forelimbs and hindlimbs. To minimize the extraction of erroneous SAGE tags from low-quality sequence data, we used a new algorithm to extract tags from -analyzed sequence data and obtained 68,406 and 68,450 SAGE tags from forelimb and hindlimb SAGE libraries, respectively. We also developed an improved method for determining the identity of SAGE tags that increases the specificity of and provides additional information about the confidence of the tag-UniGene cluster match. The most differentially expressed gene between our SAGE libraries was Pitx1. The differential expression of Tbx4, Tbx5, and several limb-specific Hox genes was also detected; however, their abundances in the SAGE libraries were low. Because numerous other tags were differentially expressed at this low level, we performed a 'virtual' subtraction with 362,344 tags from six additional nonlimb SAGE libraries to further refine this set of candidate genes. This subtraction reduced the number of candidate genes by 74%, yet preserved the previously identified regulators of limb identity. This study presents the gene expression complexity of the developing limb and identifies candidate genes involved in the regulation of limb identity. We propose that our computational tools and the overall strategy used here are broadly applicable to other SAGE-based studies in a variety of organisms. Keywords: other

Dataset Information

A molecular shift in limb identity underlies the convergent evolution and development of feathered feet

Publications

Molecular shifts in limb identity underlie development of feathered feet in two domestic avian species.

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