Chicken HOXC8 and HOXC10 genes may play a role in the altered skull morphology associated with the Crest phenotype

Abstract

One of the most intriguing traits found in domestic chickens is the Crest phenotype. This trait, characterized by a tuft of elongated feathers sprouted from the head, is found in breeds such as Polish chickens and Silkie chickens. Moreover, some crested chicken breeds also exhibit a protuberance in their anterodorsal skull region. Previous studies have strived to identify the causative factors of this trait. This study aimed to elucidate the role of chicken HOXC8 and HOXC10 in the formation of the Crest phenotype. We explored the effect of ectopic expression of HOXC8 or HOXC10 on the chicken craniofacial morphology using the RCAS retrovirus transformation system. Microcomputed tomography scanning was conducted to measure the 3D structure of the cranial bone of transgenic embryos for geometric morphometric analysis. We found that the ectopic expression of HOXC8 or HOXC10 in chicken heads caused mild morphological changes in the skull compared with the GFP‐transgenic control group. Geometric morphometric analysis showed that HOXC8 and HOXC10 transgenic groups expressed a mild upward shape change in the frontal region of the skull compared with the control group, which is similar to what is seen in the crested chicken breeds. In conclusion, this study supports findings in previous studies in which HOX genes play a role in the formation of the altered skull morphology related to the Crest phenotype. It also supports that mutations in HOX genes may contribute to intra‐ and inter‐specific variation in morphological traits in vertebrates.

Whole-Genome Sequencing for Identifying Candidate Genes Related to the Special Phenotypes of the Taihu Dianzi Pigeon

“…The crest is a cluster of feathers protruding from the head that are widely present in various birds, but the morphology of the crest varies among different birds. Research on crested chickens has shown that the HOX genes play a role in the formation of the altered skull morphology related to the crest phenotype [40]. The gene controlling the chicken crest trait may be located in the HOXC cluster adjacent to the HOXC8 gene [41].…”

Transition from natal downs to juvenile feathers: conserved regulatory switches in Neoaves

“…Whether it is simply functional redundancy or regional specificity is an interesting question. Hox genes represent the best example that elicit distinct developmental programs along the head-to-tail axis of animals and are the upstream signals of many Wnt proteins 56 , 57 , 58 , 59 , 60 , 61 . Whether distinct HOXs activate different WNTs and generate regional specific feather rachis is another interesting question.…”