SNP or paralogous sequence variant? A CONSED sequence alignment of 50 bp from an intronic segment is duplicated to six different sites in the human genome. Both forward and reverse (r) sequence reads were generated from dye-terminator sequencing reactions of PCR products amplified from monochromosomal somatic cell hybrids. Only one variant nucleotide was identified among the copies. The presence of duplicated copies on each chromosome has been verified by FISH and genomic hybridization.