Assessing MHC-B diversity in Silkie chickens

Abstract

The major histocompatibility complex ( MHC ) is a highly polymorphic region on chromosome 16, which contains numerous immune response genes, and is known to influence disease susceptibility and resistance in chickens. Variability of MHC- B haplotypes in various well-known and commercially utilized breeds has previously been identified. This study aims to understand MHC- B diversity in the Silkie breed using a high-density SNP panel that encompasses the chicken MHC- B region. DNA was obtained from 74 females and 27 males from a commercial Silkie breeder colony that is maintained through minimal genetic selection practices. A previously described panel of 90 SNPs, all located within the MHC- B region, was used to evaluate MHC- B variability in the commercial Silkie breeder colony. MHC- B haplotypes identified from the individual SNP information in the Silkie colony were compared to published haplotypes from the same region. Of the 27 haplotypes identified in the Silkie population, 8 have been previously described. Nineteen haplotypes are unique to the Silkie population and include one novel recombinant and 2 additional possible novel recombinants. Six haplotypes were found at a frequency greater than 5% of the population, of which 4 are novel. Finally, Hardy Weinberg Equilibrium ( HWE ) was calculated for the observed haplotypes, which were found to be in HWE. This study shows considerable MHC- B diversity in the Silkie breed and adds further information on variability of the MHC- B region in the chicken.

Comparison of major histocompatibility complex‐B variability in Sri Lankan indigenous chickens with five global chicken populations using MHC‐B SNP panel

“…(2020a) and Tarrant et␣al . (2020). The abbreviations of the breeds/population are as follows, Camp, Argentinian ‘Campero‐Inta’ chicken; BRL, Broiler; BPR, Barred Plymouth Rock; DBL, Dark Brown Leghorn; EPI, Epileptic synthetic line; FAY, Fayoumi; FIN, Finnish Landrace; KNC, Korean Native chicken; LS, Light Sussex; NH, New Hampshire; PC, Synthetic Columbian; RIR, Rhode Island Red; RJF, Red Jungle Fowl; SLK, USA Commercial Silkie chicken; WL, White Leghorn; WPR, White Plymouth Rock.…”

“…2017), USA Commercial Silkie chicken (Tarrant et␣al . 2020); Argentinian ‘Campero‐Inta’ chicken (Iglesias et␣al . 2019), Korean native chicken (Manjula et␣al .…”

“…2019), USA commercial Silkie chicken (Tarrant et␣al . 2020), and Korean native chicken (Manjula et␣al . 2020a).…”

“…2020a; Tarrant et␣al . 2020). This panel allowed comparisons of haplotypes in native breeds with previously identified standard haplotypes in several purebred lines with known B serological haplotypes and heritage breeds.…”

“…The relatively higher proportion of population unique haplotypes could be ancestral or have arisen as new variations owing to the recombination or different breeding practices. Several novel haplotypes were identified as possible recombinants between parental haplotypes (Fulton et al 2016a(Fulton et al ,2016b(Fulton et al , 2016aIglesias et al 2019;Manjula et al 2020a;Tarrant et al 2020). Moreover, other possible recombinants were reported when one of the parent haplotypes was not found.…”