identification of complex vertebral malformation carriers in holstein and guilan native cow breeds in iran using sscp markers

complex vertebral malformation(cvm) isanautosomal recessivehereditarydisorder caused bya point mutation in position 559 inexon 4 of the slc35a3 gene on chromosome 3 inholstein dairy cattle.this mutationchanges the function of uridine 5-diphosphate-n-acetylglucosamine transporter protein bythe substitution of valine for phenylalanine at position 180 of this protein. the disease causes premature birth, aborted fetuses and stillborn calves. latentrecessivegenesinheterozygousindividualscan be identified withhigh accuracy and repeatability using pcr-sscp technique. inthe present study,blood samples fromtwodifferent cow populations,including 100 holstein cows and100 guilan native cattle were randomly collected. specific primers were used to amplify the 177-bp fragment of exon 4 of the slc35a3 gene. no heterozygous genotype was detected in the studied samples. the lack of carriers could be a consequence of the selection against the defective gene and preventative programs for entering mutant genes into the populations or very low frequency of this gene in these populations. however, there is a risk for increased genetic defects prevalence and it is necessary to develop screening programs to identify the defective gene.