Mutations Upstream of the TBX5 and PITX1 Transcription Factor Genes Are Associated with Feathered Legs in the Domestic Chicken. Academic Article uri icon

abstract

  • Feathered leg is a trait in domestic chickens that has undergone intense selection by fancy breeders. Previous studies have shown that two major loci controlling feathered leg are located on chromosomes 13 and 15. Here, we present genetic evidence for the identification of candidate causal mutations at these loci. This was accomplished by combining classical linkage mapping using an experimental cross segregating for feathered leg and high-resolution identical-by-descent mapping using whole-genome sequence data from 167 samples of chicken with or without feathered legs. The first predicted causal mutation is a single-base change located 25kb upstream of the gene for the forelimb-specific transcription factor TBX5 on chromosome 15. The second is a 17.7-kb deletion located 200kb upstream of the gene for the hindlimb-specific transcription factor PITX1 on chromosome 13. These mutations are predicted to activate TBX5 and repress PITX1 expression, respectively. The study reveals a remarkable convergence in the evolution of the feathered-leg phenotype in domestic chickens and domestic pigeons, as this phenotype is caused by noncoding mutations upstream of the same two genes. Furthermore, the PITX1 causal variants are large overlapping deletions, 17.7kb in chicken and 44kb in pigeons. The results of the present study are consistent with the previously proposed model for pigeon that feathered leg is caused by reduced PITX1 expression and ectopic expression of TBX5 in hindlimb buds resulting in a shift of limb identity from hindlimb to more forelimb-like identity.

published proceedings

  • Mol Biol Evol

altmetric score

  • 34.45

author list (cited authors)

  • Li, J., Lee, M., Davis, B. W., Lamichhaney, S., Dorshorst, B. J., Siegel, P. B., & Andersson, L.

citation count

  • 13

complete list of authors

  • Li, Jingyi||Lee, MiOk||Davis, Brian W||Lamichhaney, Sangeet||Dorshorst, Ben J||Siegel, Paul B||Andersson, Leif

editor list (cited editors)

  • Wittkopp, P.

publication date

  • September 2020