Quantitative Trait Loci(QTL) For Analysis Using Microsatellite In The Liangshan Semi-fine Wool Sheep

Eleven microsatellites from the sheep linkage map were used to search for Quantitative Trait Loci (QTL) for wool traits using an experimental population comprising 7 paternal families of half-sibs/sire of Liangshan semi-fine wool sheep. Various phenotypes including wool fibre diameter (WFD) and staple length (SL) were measured in the flock, phenotypic correlations between wool traits using SAS program are presented. Allele frequencies of 11 microsatellites were estimated based on genotype measured using Genscan 2.0. Polymorphism information content (PIC) and heterozygosity were calculated based on allele frequencies and QTL analysis for wool traits using multiQTL program.Phenotype values and phenotypic correlations of wool fibre diameter at 18 months, 30 months and staple length at weaning, 18 months, 30months were estimated. Results in this paper were found generally agreed with those in the previous references.Every microsatellite loci analyzed were polymorphic in this flock with an average number of alleles per locus ,the average information content(PIC) and average heterozygosity are 7.8(from 5 to 11), 0.6179(from 0.3125 to 0.8410) and 0.6629 (from 0.3232 to 0.8179) respectively. Polymorphism of every microsatellite in this flock is different with the results in the Genbank. These differences were probably result from microsatellite primer for multiple PCR reaction and experimental population different from the results in the Genbank.The results of QTL analysis for wool traits using 11 microsatellites located on chromosome 3 hi the Liangshan semi-fine wool sheep revealed that a marker interval(RM150-ILSTS022) had a significant effect on staple length at weaning(SLl) (p<0.01) and staple length at 30months(SL3)(p<0.01) in the H1G4003 family using MultiQTL program indicating their potential linkage to QTLs. However, more markers between RM150 and ILSTS022 will be required to continue to locate the QTL more clearly. Two QTLs for staple length at weaning (SL1) were observed located on BMS1953 marker and in the marker interval(BMC1009-OARCP43). The result that BMC 1009 marker(Chr. 3) had a significant within sire effect onSL(P<0.01) are in agreement with that of QTL reported earlier by Allain, D. et al.(1996). However, more markers between the two peaks will be required to dissect the QTLs more clearly.In conclusion, we have detected a new QTL in this study for wool traits in the Liangshan semi-fine wool sheep which could result from the use of a different population from those used in other studies, sample size and marker density.