Quantitative trait locus affecting birth weight on bovine chromosome 5 in a F2 Gyr x Holstein population

Abstract

Segregation between a genetic marker and a locus influencing a quantitative trait in a well delineated population is the basis for success in mapping quantitative trait loci (QTL). To detect bovine chromosome 5 (BTA5) birth weight QTL we genotyped 294 F 2 Gyr (Bos indicus) x Holstein (Bos taurus) crossbreed cattle for five microsatellite markers. A linkage map was constructed for the markers and an interval analysis for the presence of QTL was performed. The linkage map indicated differences in the order of two markers relative to the reference map (http://www.marc. usda.gov). Interval analysis detected a QTL controlling birth weight (p < 0.01) at 69 centimorgans (cM) from the most centromeric marker with an effect of 0.32 phenotypic standard-error. These results support other studies with crossbred Bos taurus x Bos indicus populations.

Quantitative trait loci (QTL) mapping for growth traits on bovine chromosome 14

“…Machado et al (2003) using a composite breed developed from the cross of B. taurus and B. indicus, detected a QTL for birth weight on the same chromosome. This was probably the same QTL that was segregating in the Gyr-Holstein F2 population described above (Gasparin et al, 2005).…”

“…Most QTL mapping studies have used crosses between Bos taurus and Bos indicus cattle (Stone et al, 1999;Casas et al, 2000) since the probability of finding segregation on QTL is much higher for crossbred populations (Lynch and Walsh, 1998). As part of a project that will scan the bovine genome for several traits we have produced a reference F2 population from crosses between B. indicus Gyr and B. taurus Holstein cattle (Gasparin et al, 2005).…”

Mapping of quantitative trait loci controlling tick [Riphicephalus (Boophilus) microplus] resistance on bovine chromosomes 5, 7 and 14

“…Microsatellite markers were selected from the USDA, ARS, Meat Animal Research Center (USMARC) database at http://www.marc.usda.gov, based on chromosome position, allele number, polymorphic information content (PIC), allele range, annealing temperature and, most importantly, heterozygosity level in the F 1 bulls. PCR conditions were described in Gasparin et al. (2005), and amplified products were analysed using an ABI Prism 3100 Avant sequencer (Applied Biosystems).…”

Progresso científico em melhoramento animal no Brasil na primeira década do século XXI

“…Por se tratar de um problema tipicamente tropical, existem poucos resultados na literatura sobre QTLs para resistência a carrapatos, o que torna o Brasil uma referência nessa linha de pesquisa. Apesar de peso não ser a principal característica de interesse econômico em bovinos de leite, QTLs associados a desenvolvimento ponderal também foram relatados na população F2 desenvolvida na Embrapa Gado de Leite, por Myata et al (2007) e Gasparin et al (2005), como pode ser observado na Tabela 1. Agora, o próximo passo será identificar que genes estão por trás dos efeitos apresentados pelos QTLs mapeados.…”