Marek's disease resistant/susceptible MHC haplotypes in Xiayan chickens identified on the basis of BLB2 PCR-RFLP and BLB2/BF2 sequence analyses

Abstract

1. The aim was to analyse the variability of the BLB2/BF2 genes of Xiayan chickens to identify homozygous birds with resistance or susceptibility to Marek's disease (MD). 2. The experiment used two lines: birds from a common line were divided into Group A (unvaccinated) and Group B (vaccinated with herpesvirus of turkeys (HVT)); and birds from an MD-resistant line were divided into Group C (unvaccinated) and Group D (vaccinated with HVT). They were challenged intra-abdominally with Marek's disease virus (MDV) and genomic DNA extracted from peripheral blood lymphocytes so that polymorphism of the BLB2/BF2 genes could be analysed using polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) and nucleotide sequence analysis. 3. A 374-bp fragment of the BLB2 gene was amplified from the samples and, after digesting with restriction enzymes Alu I, Cai I, Cfr I, Hin1 I, Hinf I and Rsa I for RFLP analysis, the 6 electrophoretic patterns were analysed. Seven homozygous genotypes were found and used tentatively to identify alleles of the BLB2 gene. 4. A 765-bp fragment of the BF2 gene was amplified from the 7 samples for cloning and sequencing. 5. Six homozygous birds were confirmed from the sequenced BLB2/BF2 gene. Four birds were resistant to MD. Three birds had identical nucleotide sequences and were highly homologous with MHC haplotype B⁶, which is MD resistant. One bird had high homology with the highly MD-resistant B²¹ haplotype, and two birds were susceptible and highly homologous to the B¹⁹ haplotype, which is highly MD susceptible.

The Relationship Between the Alternative exon 7 Splice Variant of the BF Gene and MHC‐Related Marek's Disease Resistance in Chickens

“…The Xiayan is a well‐known and the largest local line of the meat‐type chicken in China. During about 5 years of research, we have arrived at almost the same conclusion that we present in this study . Also, in narrowing down the BF gene further to it's alternative exon 7 splice variant and especially in developing a snPCR assay that amplifies the alternative exon 7 splice variant of the BF gene , we have increased the chance for the rapid detection of resistant/susceptible BF haplotypes to MD .…”

Studies on the association ofBF1/BF2 gene expression patterns with traits of genetic resistance to Marek's disease in chickens

“…Chicks were obtained from an MD-resistant line and a common line of Xiayan chickens (Jin et al, 2010;Jin, Wei, Wei, Zhao, & Li, 2010a;Jin, Wei, Wei, Zhao, & Li, 2010b;Li et al, 1996) that were reared under disease-free conditions (filtered air and positive pressure isolation room). At seven days of age, six chicks from the MDresistant line were randomly divided into three 'infected' and three 'control', respectively, while six chicks from the common line were randomly divided into three 'infected' and three 'control', respectively.…”

Major histocompatibility complex B variability in Korean native chicken breeds

“…Genes in this region are functionally linked with host immunity along with other biological and production traits ( Lundén et al., 1993 ; Shiina et al., 2004 ; Molee et al., 2016 ). It is well known that MHC-B variation has an impact on specific disease resistance to several, highly pathogenic viral and bacterial diseases in poultry ( Shiina et al., 2007 ; Jin et al., 2010 ; Miller and Taylor, 2016 ) as well as internal and external parasites ( Owen et al., 2008 ; Schou et al., 2010 ). Therefore, identifying MHC-B haplotypes in indigenous chicken and developed breeds is valuable for management and productivity of the poultry industry.…”