Sequence variation of similarly-sized products. CLUSTAL W (v. 1.83; ) alignment of IGF1R PCR product sequences of hamster (A23) and river buffalo (BBU). The primer sequences are underlined. Identical nucleotides are marked with an asterisk beneath. Product melting temperatures (Tm) were estimated with Oligo 6 software, and while not identical to the melting curve generated by the SDS software, the relative differences in melt temperature between the buffalo and hamster products were similar for calculated and experimental values. Both methods indicated an approximate 2°C difference in Tm which was sufficient for discrimination by dissociation curve analysis.