02062nam a2200217 a 450000100080000000500110000800800410001910000220006024500960008226001340017850000320031252013290034465000170167365300150169070000250170570000230173070000260175370000230177970000230180270000190182518630192023-06-30       2010    bl uuuu     u00u1 u    #d1 aAZEVEDO, A. L. S.  aFine mapping of quantitative trait loci for tick resistance on BTA5.h[electronic resource]  aIn: CONFERENCE FOR THE INTERNATIONAL SOCIETY FOR ANIMAL GENETICS, 32., 2010. Edinburgo (UK). Proceedings... Edinburgo: ISAGc2010  aproceedings em  1 Pendrive.  aIn tropical regions, the cattle tick Rhipicephalus (Boophilus) microplus is a major threat to cattle production systems. The identifi cation of molecular markers linked to tick resistance would provide a better strategy for selecting resistant animals. Previous studies by our group detected QTL on BTA 5 for tick resistance in a Gyr x Holstein F2 population. This QTL was detected with moderate resolution because markers were relatively far apart from each other. Five more markers were added to BTA 5 in the region spanning the QTL in order to reduce the confi dence interval. Blood samples were collected from 480 animals (including parental, F1 and F2) and genomic DNA was extracted. PCR products were detected by capillary electrophoresis in the MegaBACE 1000 DNA sequencer. Statistical analyses were performed with GridQTL software. New association analyses were performed after saturation of the new markers and the same QTL was detected in the previously mapped location. The confi dence interval on BTA 5 was reduced from 20 to 10 cM. The phenotypic variation explained by this QTL was 3.67% and the negative additive effect indicates that Gyr animals harbor alleles that increased resistance to tick. The smaller confi dence interval increases the chance to identify candidate genes that explains tick resistance.  aResistência  aTrait loci1 aPEIXOTO, M. G. C. D.1 aPIRES, M. de F. A.1 aREGITANO, L. C. de A.1 aSILVA, M. V. G. B.1 aVERNEQUE, R. da S.1 aMACHADO, M. A.