Genotypic variability at the major histocompatibility complex (B and Rfp-Y) in Camperos broiler chickens

Facultad de Ciencias Veterinarias, Universidad de Buenos Aires, Buenos Aires, Argentina.
Animal Genetics (Impact Factor: 2.21). 05/2003; 34(2):88-95. DOI: 10.1046/j.1365-2052.2003.00944.x
Source: PubMed


Evidence for the importance of major histocompatibility complex (MHC) genotype in immunological fitness of chickens continues to accumulate. The MHC B haplotypes contribute resistance to Marek's and other diseases of economic importance. The Rfp-Y, a second cluster of MHC genes in the chicken, may also contribute to disease resistance. Nevertheless, the MHC B and Rfp-Y haplotypes segregating in broiler chickens are poorly documented. The Camperos, free-range broiler chickens developed in Argentina, provide an opportunity to evaluate MHC diversity in a genetically diverse broiler stock. Camperos are derived by cross-breeding parental stocks maintained essentially without selection since their founding. We analysed 51 DNA samples from the Camperos and their parental lines for MHC B and Rfp-Y variability by restriction fragment pattern (rfp) and SSCP typing methods for B-G, B-F (class Ia), B-Lbeta (class II) and Y-F (class Ib) diversity. We found evidence for 38 B-G genotypes. The Camperos B-G patterns were not shared with White Leghorn controls, nor were any of a limited number of Camperos B-G gene sequences identical to published B-G sequences. The SSCP assays provided evidence for the presence of at least 28 B-F and 29 B-Lbeta genotypes. When considered together B-F, B-L, and B-G patterns provide evidence for 40 Camperos B genotypes. We found even greater Rfp-Y diversity. The Rfp-Y class I-specific probe, 163/164f, revealed 44 different rfps among the 51 samples. We conclude that substantial MHC B and Rfp-Y diversity exists within broiler chickens that might be drawn upon in selecting for desirable immunological traits.

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Available from: Gabriela Marisa Iglesias
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    • "This additional level of variation results in production difficulties for haplotype-specific antisera which can yield inaccurate haplotype identification. With the advent of molecular biology tools, B haplotypes can now be determined with several methods including two-dimensional (2-D) gels (Miller et al. 1984), restriction fragment length polymorphism (RFLP) (Miller et al. 1988; Juul-Madsen et al. 1993; Emara et al. 2002; Landesman et al. 1993; Iglesias et al. 2003), DNA sequence (Sung et al. 1993; Miller et al. 2004), singlestrand conformation polymorphism (Goto et al. 2002), and sequence-specific polymerase chain reaction (SS-PCR) (Zheng et al. 1999; Livant and Ewald 2005). These tools have also been applied to study MHC diversity in broilertype chickens (Li et al. 1997, 1999; Livant et al. 2001; Livant and Ewald 2005). "
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    ABSTRACT: The chicken major histocompatibility complex (MHC) is commonly defined by serologic reactions of erythrocytes with antibodies specific to the highly polymorphic MHC class I (BF) and MHC class IV (BG) antigens. The microsatellite marker LEI0258 is known to be physically located within the MHC, between the BG and BF regions. DNA from various serologically defined MHC haplotypes was amplified by polymerase chain reaction with primers surrounding this marker. Twenty-six distinctive allele sizes were identified. Some serologically well-defined MHC haplotypes shared a common LEI0258 allele size but could be distinguished either by the addition of information from another nearby marker (MCW0371) or by small indels or single nucleotide polymorphism (SNP) differences between the alleles. The association between LEI0258 allele and serologically defined MHC haplotype was very consistent for the same haplotype from multiple sources. Sequence information for the region defined by LEI0258 was obtained for 51 different haplotypes. Two internal repeats whose lengths were 13 and 12 bp, respectively, are the primary basis for allelic variability. Allele size variation ranges from 182 to 552 bp. Four indels and five SNPs in the surrounding sequence provide additional means for distinguishing alleles. Typing with LEI0258 and MCW0371 will be useful in identifying MHC haplotypes in outbred populations of chickens particularly for the initial development of serological reagents.
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    • "Jarvi et al. (1999) identified B-G-like genes in cranes. After that, the clones of exons 1 and 2 of B-G gene were generated by PCR from genomic DNA samples of Camperos broiler chickens and genetic variability within the B-G gene family was revealed by single stranded conformational polymorphism (SSCP) assays (Iglesias et al., 2003). "
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    • "Resistência a doenças: o MHC das aves tem sido uma região do genoma investigada e altamente polimórfica (Nishibori et al. 2000; Iglesias et al 2003). Em uma população específica para estudos de resistência à Salmonella enteritidis (SE), diferentes genes candidatos foram investigados. "

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