DETECTION OF QTL AFFECTING FLEECE TRAITS IN ANGORA GOATS ON CHI 1 E.M. Cano 1 , G. Marrube 2 , S. Debenedetti 3 , F. Bidinost 3 , D. Roldan 1 , M. Abad 3 , D. Allain 4 , H. Taddeo 3 and M.A. Poli 1 1 Instituto de Genética, CICVyA-INTA, CC 25, CP 1712-Castelar, Argentina 2 Facultad de Ciencias Veterinarias, U.B.A., Area de Genética-Buenos Aires, Argentina 3 Estación Experimental Agropecuaria Bariloche-INTA, CP 8400-Río Negro, Argentina 4 INRA Station d'Amélioration Génétique des Animaux BP27, 31326 Castanet, Tolosan, France mcano@cnia.inta.gov.ar Summary Some previous studies have indicated the presence of genes or gene families involved in fleece traits in different species. The aim of the present study was to confirm the location of a QTL and to search new Quantitative Traits Loci (QTL) on goat chromosome (CHI) 1 using new microsatellites and enlarged families in Angora goats. The population analyzed had a total of 634 kids from 14 Angora bucks. Seventeen phenotypic fleece traits were recorded. An interval analysis was performed under a half-sib model using the QTL Express program. Our results confirm a QTL for Coefficient of Variation of Average Fiber Diameter (CVAFD) and we found new QTL for percentage of fiber with diameter over 30 m (F30 1 ), percentage of Continuous Medullated Fibers (CONT 2 ) and Greasy Fleece Weight (GFW 2 ) on CHI1 in Angora goats. Further investigations should concern diminishing the confidence interval increasing the number of kids in existing families and making a fine mapping on the candidate regions. Introduction In recent decades, the molecular biology techniques developed have made possible to construct comprehensive marker maps in different species which allow mapping of Quantitative Traits Loci (QTL) influencing economically important traits, including fleece and wool traits. Once the location of a trait is determined by linkage to the markers, possible candidate genes controlling the trait can be inferred. A subset of genes that are mapped in humans, mice and sheep have also been mapped in goat; these genes serve as “anchors” across the comparative maps of the different species. Some previous studies have indicated the presence of genes or gene families involved in fleece traits in sheep (reviewed by Purvis and Franklin, 2005), and the hair in rabbit (Allain et al., 2004), human (Rogers et al., 2004) and mice (Pruett et al., 2004). In a genome screen for QTL in Angora goats, Cano et al. (2006), reported the first results on putative QTL affecting Coefficient of variation of Average Fiber Diameter (CVAFD), percentage of fiber kemp (KEMP), percentage of Discontinuous Medullated Fibers (DISC) and Staple Length (SL). The aim of this study was to confirm the location of a QTL on CHI1 and to identify new QTL in the same chromosome using new microsatellites and enlarged families in Angora goats. Materials and methods Animals and Phenotype Traits. The population analyzed had a total of 634 kids from 14 Angora bucks. The number of half-sib offspring per buck ranged between 20 to 85 kids. The population was created in five batches (years 2000 to 2004). Mid-side fleece samples were taken from kids at 4 and 11 months of age. Fleece samples were analyzed at the Textile Fibers Laboratory of INTA Bariloche. Seventeen phenotypic fleece traits were recorded, eight at 4 months old ( 1 ) and the follow nine at 11 months old ( 2 ): Average Fiber Diameter (AFD; m), Coefficient of Variation of AFD (CVAFD; %), the percentage of fiber with diameter over