Source and Description of Primers. The initial primers for the PCR were designed based on human DNA sequence (accession no. X92412; Kolmerer et al., 1996). The position of the forward and reverse primers corresponded to exon 3 and exon 5, respectively. These primers are expected to amplify a fragment of 1.93 kb from human DNA. A PCR fragment of 2.1 kb was amplified from porcine genomic DNA. Partial sequences were compared with the human sequence, which showed 90% (1,038/1,159 bp) nucleotide identity. The pig sequences (AF124849-50) were then used to design additional primers that amplified a 1.8-kb fragment of pig TTN and were used both for physical mapping using the somatic cell hybrid panel (SCHP) and for PCR-RFLP analysis.