Masayuki Sakagami
Laboratory of Molecular and Cell Biology, Equine Research Institute, JRA, Tokyo 154, Japan
The phenomenon of addition of a single adenine residue with thermostable DNA polymerase at each 3' end of the duplex PCR fragment is well known, although the rate of such addition has not been clarified. The PCR polymorphism is increasingly utilized in genome analysis as the landmark of linkage study, population genetics and individual identification. Especially, the correct detection of certain alleles has received much attention as DNA markers for legal medicine and animal pedigree tests. However, it is not easy to determine the variable number of STRs when comparing alleles. As a consequence, the result from worldwide research institutions in the international comparison test of the ISBC (International Stud Book Committee)/ISAG (International Society for Animal Genetics) in 1994 regarding thoroughbred-horse parentage analysis based on STR polymorphism displayed a certain degree of variance. In this experiment, we demonstrated mononucleotide repeat polymorphism within the 3' end (poly-A region) of equine SINE (ERE-1-2*) and dinucleotide repeat polymorphism (ECA-2**). The introduction of a simple and reliable method for detection of STR polymorphisms by using an automatic DNA sequencer, in order to prevent terminal transferase-like activity of the effects of DNA polymerase, will be discussed.
*Sakagami M. et al. (1994) J. Mol. Biol. 239:731-735.
** Sakagami M. et al (1995) Anim. Genet. 26:123-124.
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