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Genome-wide association study for Marek's disease mortality in layer chickens
Anna Wolc1, Jesus Arango, Tomasz Jankowski
1Department of Genetic and Animal Breeding, Poznan University of Life Sciences, Wolynska Street 33, 60-637 Poznan, Poland. awolc@jay.up.pozman.pl
Avian Diseases
|August 2, 2013
Summary
This study identified specific genomic regions linked to Marek's disease virus resistance in chickens. These findings aid in selecting poultry for improved disease resilience.
Area of Science:
- Animal Genetics
- Poultry Science
- Disease Resistance
Background:
- Marek's disease virus (MDV) causes significant mortality in layer chickens.
- Genome-wide association studies (GWAS) are crucial for identifying genetic factors influencing disease resistance.
- Understanding the genetic basis of MDV resistance can improve poultry breeding strategies.
Purpose of the Study:
- To identify genomic regions associated with mortality from MDV infection in layer chickens using GWAS.
- To evaluate the effectiveness of Bayesian variable selection methods in detecting quantitative trait loci (QTL) for MDV resistance.
- To assess the impact of progeny group size on the accuracy of genomic region localization.
Main Methods:
- A genome-wide association study (GWAS) was conducted on 253 genotyped sires from a brown-egg layer line.
- Bayesian variable selection methods (BayesB and BayesCpi) were applied to single-nucleotide polymorphism (SNP) data.
- Mortality data from experimental MDV challenge were analyzed, with consideration for progeny group sizes.
- Genomic regions explaining the largest proportion of genetic variance were identified.
Main Results:
- Genetic markers explained approximately 11% of the phenotypic variation in MDV mortality.
- Specific genomic regions on chromosomes 2, 3, 4, 9, 15, 18, and 21 were significantly associated with MDV resistance.
- Weighting analyses by progeny group size improved the localization of associated genomic regions.
- Correlations between genomic estimated breeding values and progeny mortality ranged from 0.02 to 0.20.
Conclusions:
- Genomic regions on chromosomes 2, 3, 4, 9, 15, 18, and 21 are valuable targets for selection to enhance MDV resistance in layers.
- Accounting for progeny group size in GWAS analyses is critical for accurate identification of disease resistance loci.
- The identified genomic regions provide a foundation for marker-assisted selection programs in poultry breeding.
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