The majority of traits selected in livestock production are quantitative, and the observed phenotype is the result of the effect of many quantitative trait loci (QTL) and environmental factors (RON et al. 1994). QTLs account for only a small fraction of total variance, and can be located by genetic linkage to a genetic marker (SOLLER1990; WELLER1992). Therefore, by using many genetic markers associated with the same trait, it is possible to explain a good part of the genetic variance. Microsatellites, a new class of genetic markers that are highly variable and polymorphic (LITTand LUTY1989;WEBERand MAY1989), are DNA regions composed of few repeated short-sequence motifs, which are present in the genome of different species (HAMADAet al. 1984), including bovine species (FRIESet al. 1990). Microsatellite loci occur frequently, randomly and uniformly distributed throughout the genome (DIETRICHet al. 1992;HEARNeEt al. 1992;WEBER1990).They exhibit considerable polymorphism, due to variation in the number of repeat units, and there are often multiple alleles, probably because of past slippage mutation (TAUTZand RENZ1984; SCHLOTTERER and TAUTZ1992). One of the advantages of microsatellites is that the banding patterns are extremely simple, showing one or two strong bands, and alleles differ in size by integer multiples of the repeat unit. They can be easily detected through simple polymerase chain reaction amplification if the two flanking regions are known, and registered in open access gene banks (i.e. EMBL). Pedigree studies have shown that microsatellites are inherited in typical Mendelian co- dominant fashion (LITT and LUTY1989). As microsatellites are so abundant in the genome of a species, they can be used as markers, exploiting their association with QLTs and including them in marker-assisted selection programmes to increase the rate of genetic progress (GEORGESet al. 1993). The purpose of this research was to associate three identified microsatellites with beef-performance traits. Because a crossbred population was studied in which marker and QTL are in linkage disequilibrium, the aim of the analysis was to evaluate the mere substitution effect of the marker on the trait.

Exploitation of microsatellites as genetic markers of beef-performance traits in Piemontese x Chianina crossbred cattle

COMINCINI, SERGIO;FERRETTI, LUCA;
1996-01-01

Abstract

The majority of traits selected in livestock production are quantitative, and the observed phenotype is the result of the effect of many quantitative trait loci (QTL) and environmental factors (RON et al. 1994). QTLs account for only a small fraction of total variance, and can be located by genetic linkage to a genetic marker (SOLLER1990; WELLER1992). Therefore, by using many genetic markers associated with the same trait, it is possible to explain a good part of the genetic variance. Microsatellites, a new class of genetic markers that are highly variable and polymorphic (LITTand LUTY1989;WEBERand MAY1989), are DNA regions composed of few repeated short-sequence motifs, which are present in the genome of different species (HAMADAet al. 1984), including bovine species (FRIESet al. 1990). Microsatellite loci occur frequently, randomly and uniformly distributed throughout the genome (DIETRICHet al. 1992;HEARNeEt al. 1992;WEBER1990).They exhibit considerable polymorphism, due to variation in the number of repeat units, and there are often multiple alleles, probably because of past slippage mutation (TAUTZand RENZ1984; SCHLOTTERER and TAUTZ1992). One of the advantages of microsatellites is that the banding patterns are extremely simple, showing one or two strong bands, and alleles differ in size by integer multiples of the repeat unit. They can be easily detected through simple polymerase chain reaction amplification if the two flanking regions are known, and registered in open access gene banks (i.e. EMBL). Pedigree studies have shown that microsatellites are inherited in typical Mendelian co- dominant fashion (LITT and LUTY1989). As microsatellites are so abundant in the genome of a species, they can be used as markers, exploiting their association with QLTs and including them in marker-assisted selection programmes to increase the rate of genetic progress (GEORGESet al. 1993). The purpose of this research was to associate three identified microsatellites with beef-performance traits. Because a crossbred population was studied in which marker and QTL are in linkage disequilibrium, the aim of the analysis was to evaluate the mere substitution effect of the marker on the trait.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11571/131391
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