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Aldersey JE, Sonstegard TS, Williams JL, Bottema CDK. Understanding the effects of the bovine POLLED variants. Anim Genet 2020; 51:166-176. [PMID: 31999853 DOI: 10.1111/age.12915] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/06/2020] [Indexed: 12/31/2022]
Abstract
Horns are paired appendages on the head of bovine species, comprising an inner bony core and outer keratin sheath. The horn bud forms during early fetal development but ossification of the developing horn does not occur until approximately 1 month after birth. Little is known about the genetic pathways that lead to horn growth. Hornless, or polled, animals are found in all domestic bovids. Histological studies of bovine fetuses have shown that the horn bud does not form in polled individuals. There are currently four known genetic variants for polledness in cattle on BTA1. All of the variants are intergenic, but probably affect regulation of nearby genes or long non-coding RNAs. Transcriptomic studies suggest that the expression of two nearby long non-coding RNAs are affected by the Celtic POLLED variant, but further studies are required to confirm these data. Candidate genes located elsewhere in the genome are involved in regulating bone formation and epithelial-to-mesenchymal transition. Expression of one of these candidate genes, RXFP2, appears to be reduced in the fetal horn bud of polled animals carrying the Celtic variant compared with horned individuals. Investigating horn ontogenesis and the genetic pathway by which the POLLED variants prevent horn development has implications for cattle breeding. If the genetic basis of horn bud formation and polledness is better understood, then new targets may be identified for precision genome editing to create polled individuals.
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Affiliation(s)
- J E Aldersey
- Davies Research Centre, School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy Campus, Adelaide, SA, 5371, Australia
| | | | - J L Williams
- Davies Research Centre, School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy Campus, Adelaide, SA, 5371, Australia
| | - C D K Bottema
- Davies Research Centre, School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy Campus, Adelaide, SA, 5371, Australia
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Falomir-Lockhart AH, Ortega Masague MF, Rudd Garces G, Zappa ME, Peral García P, Morales HF, Holgado FD, Rogberg Muñoz A, Giovambattista G. Polledness in Argentinean Creole cattle, five centuries surviving. Anim Genet 2019; 50:381-385. [PMID: 31179563 DOI: 10.1111/age.12803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/09/2019] [Indexed: 11/26/2022]
Abstract
Polledness has been shown to have autosomal Mendelian inheritance, with the polled locus being dominant to the horned locus. This trait was mapped to the BTA1 centromeric end in several breeds. One of the distinctive attributes of Creole cattle, such as the Argentinean Creole, is the presence of long, lyre-shaped horns. However, polled native animals were reported before the introduction of modern selected European breeds. Here, we studied the origin of the polled mutation, either independent or introgressed, in a Creole line from the Creole cattle founder group at the IIACS-INTA Leales Experimental Station (northwest Argentina). The study sample (65 animals: 26 horned and 39 polled) was genotyped using high-density SNP microarrays and three previously reported genetic markers (P202 ID , P80kb ID and PG ). A genome-wide association study, selection signatures, linkage disequilibrium analysis and copy number variations were used to detect the responsible region and the segregating haplotypes/alleles. The interval mapped in the Leales herd (1.23-2.13 Mb) overlapped with the region previously reported in several European cattle breeds, suggesting that the same locus could be segregating in this population. The previously reported variants PF and PG were not detected, thus dismissing the Holstein-Friesian and Nellore origins of the polled phenotype in this native breed. Conversely, the presence of the Celtic variant PC suggests an almost complete co-segregation. The cluster analysis rejected the hypothesis of recent introgression, which is compatible with the historical record of polled Creole cattle in northwest Argentina.
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Affiliation(s)
- A H Falomir-Lockhart
- Facultad de Ciencias Veterinarias UNLP, IGEVET - Instituto de Genética Veterinaria (UNLP-CONICET LA PLATA), Calle 60 y 118 s/n, CC 296, 1900, La Plata, Buenos Aires, Argentina
| | - M F Ortega Masague
- IIACS - Instituto de Investigación Animal del Chaco Semiárido, (CIAP-INTA), Chañar Pozo s/n, 4113, Leales, Tucumán, Argentina
| | - G Rudd Garces
- Facultad de Ciencias Veterinarias UNLP, IGEVET - Instituto de Genética Veterinaria (UNLP-CONICET LA PLATA), Calle 60 y 118 s/n, CC 296, 1900, La Plata, Buenos Aires, Argentina
| | - M E Zappa
- Facultad de Ciencias Veterinarias UNLP, IGEVET - Instituto de Genética Veterinaria (UNLP-CONICET LA PLATA), Calle 60 y 118 s/n, CC 296, 1900, La Plata, Buenos Aires, Argentina
| | - P Peral García
- Facultad de Ciencias Veterinarias UNLP, IGEVET - Instituto de Genética Veterinaria (UNLP-CONICET LA PLATA), Calle 60 y 118 s/n, CC 296, 1900, La Plata, Buenos Aires, Argentina
| | - H F Morales
- Facultad de Ciencias Veterinarias UNLP, IGEVET - Instituto de Genética Veterinaria (UNLP-CONICET LA PLATA), Calle 60 y 118 s/n, CC 296, 1900, La Plata, Buenos Aires, Argentina
| | - F D Holgado
- IIACS - Instituto de Investigación Animal del Chaco Semiárido, (CIAP-INTA), Chañar Pozo s/n, 4113, Leales, Tucumán, Argentina
| | - A Rogberg Muñoz
- Facultad de Ciencias Veterinarias UNLP, IGEVET - Instituto de Genética Veterinaria (UNLP-CONICET LA PLATA), Calle 60 y 118 s/n, CC 296, 1900, La Plata, Buenos Aires, Argentina.,Departamento de Producción Animal, Facultad de Agronomía, Cátedra de Mejoramiento Genético Animal, Universidad de Buenos Aires, Av. San Martin 4453, C1417DSE, Buenos Aires, Argentina
| | - G Giovambattista
- Facultad de Ciencias Veterinarias UNLP, IGEVET - Instituto de Genética Veterinaria (UNLP-CONICET LA PLATA), Calle 60 y 118 s/n, CC 296, 1900, La Plata, Buenos Aires, Argentina
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