Limits...
Fine-mapping QTL for mastitis resistance on BTA9 in three Nordic red cattle breeds.

Sahana G, Lund MS, Andersson-Eklund L, Hastings N, Fernandez A, Iso-Touru T, Thomsen B, Viitala S, Sørensen P, Williams JL, Vilkki J - Anim. Genet. (2008)

Bottom Line: This QTL showed a pleiotropic effect on SCS in the DR and SRB breeds.This QTL was also associated with yield traits in DR but not in FA or SRB.No QTL were found for udder conformation traits on chromosome 9.

View Article: PubMed Central - PubMed

Affiliation: Department of Genetics and Biotechnology, Faculty of Agricultural Sciences, Aarhus University, Research Centre Foulum, DK-8830 Tjele, Denmark. goutam.sahana@agrsci.dk

ABSTRACT
A QTL affecting clinical mastitis and/or somatic cell score (SCS) has been reported previously on chromosome 9 from studies in 16 families from the Swedish Red and White (SRB), Finnish Ayrshire (FA) and Danish Red (DR) breeds. In order to refine the QTL location, 67 markers were genotyped over the whole chromosome in the 16 original families and 18 additional half-sib families. This enabled linkage disequilibrium information to be used in the analysis. Data were analysed by an approach that combines information from linkage and linkage disequilibrium, which allowed the QTL affecting clinical mastitis to be mapped to a small interval (<1 cM) between the markers BM4208 and INRA084. This QTL showed a pleiotropic effect on SCS in the DR and SRB breeds. Haplotypes associated with variations in mastitis resistance were identified. The haplotypes were predictive in the general population and can be used in marker-assisted selection. Pleiotropic effects of the mastitis QTL were studied for three milk production traits and eight udder conformation traits. This QTL was also associated with yield traits in DR but not in FA or SRB. No QTL were found for udder conformation traits on chromosome 9.

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QTL profiles (— LA; ♦ LDLA;  5% significant threshold) for the two-trait single QTL model affecting clinical mastitis and somatic cell score in combined breed data.
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fig05: QTL profiles (— LA; ♦ LDLA; 5% significant threshold) for the two-trait single QTL model affecting clinical mastitis and somatic cell score in combined breed data.

Mentions: Multi-trait analysis of CM and SCS was carried out using both MTP and MTL models in the combined data from three breeds (Table 6; Fig. 5). The combined data with an MTP model gave an LDLA peak with high LRT at 74.4 cM, between markers INRA144 and INRA084. This QTL explained 42% and 14% of the genetic variation in CM and SCS respectively. The correlation between the QTL effects for these two traits was estimated to be 0.72. A LA with the MTL model in the three breeds positioned the CM QTL at 79.7 cM and the SCS QTL at 95.1 cM. When LDLA analysis was carried out with a 2-trait model with QTL affecting CM and not SCS (MTCM), the highest LRT (12.0) was at 74.4 cM between INRA144 and INRA084. In a similar 2-trait model, when the QTL was fitted to affect SCS only and not CM (MTSCS), the peak disappeared.


Fine-mapping QTL for mastitis resistance on BTA9 in three Nordic red cattle breeds.

Sahana G, Lund MS, Andersson-Eklund L, Hastings N, Fernandez A, Iso-Touru T, Thomsen B, Viitala S, Sørensen P, Williams JL, Vilkki J - Anim. Genet. (2008)

QTL profiles (— LA; ♦ LDLA;  5% significant threshold) for the two-trait single QTL model affecting clinical mastitis and somatic cell score in combined breed data.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2655356&req=5

fig05: QTL profiles (— LA; ♦ LDLA; 5% significant threshold) for the two-trait single QTL model affecting clinical mastitis and somatic cell score in combined breed data.
Mentions: Multi-trait analysis of CM and SCS was carried out using both MTP and MTL models in the combined data from three breeds (Table 6; Fig. 5). The combined data with an MTP model gave an LDLA peak with high LRT at 74.4 cM, between markers INRA144 and INRA084. This QTL explained 42% and 14% of the genetic variation in CM and SCS respectively. The correlation between the QTL effects for these two traits was estimated to be 0.72. A LA with the MTL model in the three breeds positioned the CM QTL at 79.7 cM and the SCS QTL at 95.1 cM. When LDLA analysis was carried out with a 2-trait model with QTL affecting CM and not SCS (MTCM), the highest LRT (12.0) was at 74.4 cM between INRA144 and INRA084. In a similar 2-trait model, when the QTL was fitted to affect SCS only and not CM (MTSCS), the peak disappeared.

Bottom Line: This QTL showed a pleiotropic effect on SCS in the DR and SRB breeds.This QTL was also associated with yield traits in DR but not in FA or SRB.No QTL were found for udder conformation traits on chromosome 9.

View Article: PubMed Central - PubMed

Affiliation: Department of Genetics and Biotechnology, Faculty of Agricultural Sciences, Aarhus University, Research Centre Foulum, DK-8830 Tjele, Denmark. goutam.sahana@agrsci.dk

ABSTRACT
A QTL affecting clinical mastitis and/or somatic cell score (SCS) has been reported previously on chromosome 9 from studies in 16 families from the Swedish Red and White (SRB), Finnish Ayrshire (FA) and Danish Red (DR) breeds. In order to refine the QTL location, 67 markers were genotyped over the whole chromosome in the 16 original families and 18 additional half-sib families. This enabled linkage disequilibrium information to be used in the analysis. Data were analysed by an approach that combines information from linkage and linkage disequilibrium, which allowed the QTL affecting clinical mastitis to be mapped to a small interval (<1 cM) between the markers BM4208 and INRA084. This QTL showed a pleiotropic effect on SCS in the DR and SRB breeds. Haplotypes associated with variations in mastitis resistance were identified. The haplotypes were predictive in the general population and can be used in marker-assisted selection. Pleiotropic effects of the mastitis QTL were studied for three milk production traits and eight udder conformation traits. This QTL was also associated with yield traits in DR but not in FA or SRB. No QTL were found for udder conformation traits on chromosome 9.

Show MeSH
Related in: MedlinePlus