Copy number variation in HOXB7 and HOXB8 involves in the formation of beard trait in chickens

Abstract

The derived feathering phenotype beard in domestic birds is an ideal resource to investigate the genetic mechanisms controlling feather development and differentiation. In the present study, we performed a GWAS and QTL linkage analysis on the trait of beard in Beijing fatty chicken. One major QTL (1.2-1.9 Mb) was identified that could explain 34% of the phenotypic variation. The copy number variation that was copied from the region (GGA27:3 578 409-3 592 890 bp) containing homebox B7 (HOXB7) and homebox B8 (HOXB8) was validated to be only exhibited in the genome of bearded chickens. Proteinprotein interaction analysis indicated that HOXB7 and HOXB8 proteins could highly interact with the HOXB family members, including HOXB4, HOXB5 and HOXB6, whose genomic locations near HOXB7 and HOXB8 suggested that they may regulate their family members to involve in the formation of the beard trait in chickens. Overall, our work provides basic data for understanding the mechanisms regulating beard development and differentiation.

Population Genomic Sequencing Delineates Global Landscape of Copy Number Variations that Drive Domestication and Breed Formation of in Chicken

“…YOU chicken is a Chinese native breed with special appearance characteristics, including crests, beards, feathered legs, and polydactyly. Recently, Yang et al (2020) deciphered that the copy number variation in HOXB7 and HOXB8 is responsible for the beard trait, which coincides exactly with the CNV detected in our study, especially exhibiting two copy number increase in YOU chicken.…”

Fourth Report on Chicken Genes and Chromosomes 2022

“…For instance, a duplicated sequence close to the first intron of SOX5 has been linked to the peacomb phenotype [Wright et al, 2009], while an inverted duplication including EDN3 is associated with dermal hyperpigmentation in chicken [Dorshorst et al, 2011]. In addition, partial duplication of PRLR has been related to late feathering [Elferink et al, 2008], whereas a CNV linked with the HOXB7 and HOXB8 genomic region has been associated with the beard phenotype [Yang KX et al, 2020] in chicken.…”

Genome-wide association analysis of nine reproduction and morphological traits in three goat breeds from Southern China

“…Previously, a GWAS performed on the Beijing fatty chicken showed that the copy number variations in the homeobox B7 ( HOXB7 ) and homeobox B8 ( HOXB8 ) genes were involved in forming beard traits [ 30 ]. While in goats, evaluating the beard traits has been carried out in some goat breeds in Southwest China recently [ 2 ], but no previous studies have so far investigated the goat beard traits by genome selection approach.…”