Characterization, chromosomal localization, and genetic variation of the alpha subunit of porcine eighth component of complement.

The complete amino acid sequence of the porcine alpha subunit of the eighth component of complement (C8A) was determined by characterizing the full length cDNA clone isolated from a porcine liver cDNA library. Porcine C8A was found to be similar to human and rabbit C8A in length, leader sequence, conserved cysteine residues, cysteine-rich modules, and overall sequence. Differences in the amino acid sequence among the three species were detected in the proposed candidate site for CD59 recognition (amino acids 352-389). The porcine C8A gene was physically mapped to chromosome 6q33-35 by in situ hybridization using the porcine bacterial artificial chromosome (BAC) clone as a hybridization probe. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of C8A was performed using the restriction enzyme Hha I. Distribution of the alleles was determined in pigs (n = 173) of several different breeds. Estimates of allele frequency of the 201 bp fragment were 0.22,.0.43,.0.04,.0.50,.0.58,.0.50,.0.98, and 0.91 in Landrace, Large White, Duroc, Berkshire, Jinhua, Crown Miniature Pig, wild boar, and Meishan, respectively.