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Fulton JE, Mason AS, Wolc A, Arango J, Settar P, Lund AR, Burt DW. The impact of endogenous Avian Leukosis Viruses (ALVE) on production traits in elite layer lines. Poult Sci 2021; 100:101121. [PMID: 33975038 PMCID: PMC8131724 DOI: 10.1016/j.psj.2021.101121] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 01/26/2021] [Accepted: 02/26/2021] [Indexed: 11/28/2022] Open
Abstract
Avian Leukosis Virus subgroup E (ALVE) integrations are endogenous retroviral elements found in the chicken genome. The presence of ALVE has been reported to have negative impacts on multiple traits, including egg production and body weight. The recent development of rapid, inexpensive and specific ALVE detection methods has facilitated their characterization in elite commercial egg production lines across multiple generations. The presence of 20 ALVE was examined in 8 elite lines, from 3 different breeds. Seventeen of these ALVE (85%) were informative and found to be segregating in at least one of the lines. To test for an association between specific ALVE inserts and traits, a large genotype by phenotype study was undertaken. Genotypes were obtained for 500 to 1500 males per line, and the phenotypes used were sire-daughter averages. Phenotype data were analyzed by line with a linear model that included the effects of generation, ALVE genotype and their interaction. If genotype effect was significant, the number of ALVE copies was fitted as a regression to estimate additive ALVE gene substitution effect. Significant associations between the presence of specific ALVE inserts and 18 commercially relevant performance and egg quality traits, including egg production, egg weight and albumen height, were observed. When an ALVE was segregating in more than one line, these associations did not always have the same impact (negative, positive or none) in each line. It is hypothesized that the presence of ALVE in the chicken genome may influence production traits by 3 mechanisms: viral protein production may modulate the immune system and impact overall production performance (virus effect); insertional mutagenesis caused by viral integration may cause direct gene alterations or affect gene regulation (gene effect); or the integration site may be within or adjacent to a quantitative trait region which impacts a performance trait (linkage disequilibrium, marker effect).
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Affiliation(s)
- Janet E Fulton
- Department of Research and Development, Hy-Line International, Dallas Center, IA 50063, USA.
| | - Andrew S Mason
- Jack Birch Unit for Molecular Carcinogenesis, Department of Biology and The York Biomedical Research Institute, The University of York, York, YO10 5DD, United Kingdom
| | - Anna Wolc
- Department of Research and Development, Hy-Line International, Dallas Center, IA 50063, USA; Department of Animal Science, Iowa State University, Ames, IA 50011, USA
| | - Jesus Arango
- Department of Research and Development, Hy-Line International, Dallas Center, IA 50063, USA
| | - Petek Settar
- Department of Research and Development, Hy-Line International, Dallas Center, IA 50063, USA
| | - Ashlee R Lund
- Department of Research and Development, Hy-Line International, Dallas Center, IA 50063, USA
| | - David W Burt
- The University of Queensland, Brisbane, Queensland, 4072, Australia
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Chiu ES, VandeWoude S. Endogenous Retroviruses Drive Resistance and Promotion of Exogenous Retroviral Homologs. Annu Rev Anim Biosci 2020; 9:225-248. [PMID: 33290087 DOI: 10.1146/annurev-animal-050620-101416] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Endogenous retroviruses (ERVs) serve as markers of ancient viral infections and provide invaluable insight into host and viral evolution. ERVs have been exapted to assist in performing basic biological functions, including placentation, immune modulation, and oncogenesis. A subset of ERVs share high nucleotide similarity to circulating horizontally transmitted exogenous retrovirus (XRV) progenitors. In these cases, ERV-XRV interactions have been documented and include (a) recombination to result in ERV-XRV chimeras, (b) ERV induction of immune self-tolerance to XRV antigens, (c) ERV antigen interference with XRV receptor binding, and (d) interactions resulting in both enhancement and restriction of XRV infections. Whereas the mechanisms governing recombination and immune self-tolerance have been partially determined, enhancement and restriction of XRV infection are virus specific and only partially understood. This review summarizes interactions between six unique ERV-XRV pairs, highlighting important ERV biological functions and potential evolutionary histories in vertebrate hosts.
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Affiliation(s)
- Elliott S Chiu
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523, USA; ,
| | - Sue VandeWoude
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523, USA; ,
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Urbani N, Hartmann W, Kuhnlein U, Zadworny D, Heil G. Incidence of endogenous viral genes in Leghorn strains of different origin, each with sublines of a different genotype for resistance to avian leukosis virus infection. J Anim Breed Genet 2011. [DOI: 10.1111/j.1439-0388.1995.tb00581.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Gavora JS, Spencer JL, Benkel B, Gagnon C, Emsley A, Kulenkamp A. Endogenous viral genes influence infection with avian leukosis virus. Avian Pathol 2007; 24:653-64. [DOI: 10.1080/03079459508419105] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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