In this study, ten native Turkish sheep breeds were sampled to evaluate Y chromosomal genetic variation. Two regions of the SRY gene, one region each of the DBY and AMEL genes and SRYM18 Y-specific microsatellite locus were sequenced. While no base substitutions were found in the sequenced regions of SRY. DBY and AMELY, most of the Turkish sheep breeds have some variations of SRYM18. in total, we found three different SRYM18 alleles that were 141, 143 and 145 bp in length. The distribution of these alleles was different among fat-tailed sheep breeds and the thin-tailed sheep breeds. While the most common allele was 143 bp among the breeds, the 141-bp allele was also observed in both fat-tailed and thin-tailed breeds. The 145-bp allele was only found in the fat-tailed sheep at low frequency. (C) 2010 Elsevier B.V. All rights reserved.