CHARACTERIZATION, CHROMOSOMAL LOCALIZATION, AND GENETIC-VARIATION OF THE ALPHA-SUBUNIT OF PORCINE 8TH COMPONENT OF COMPLEMENT

The complete amino acid sequence of the porcine ct subunit of the eigh th component of complement (C8A) was determined by characterizing the full length cDNA clone isolated fi om a porcine liver cDNA library. Po rcine C8A was found to be similar to human and rabbit CBA in length, l eader sequence. conserved cysteine residues, cysteine-rich modules, an d overall sequence. Differences in the amino acid sequence among the t hree species were detected in the proposed candidate site for CD59 rec ognition (amino acids 352-389). The porcine C8A gene was physically ma pped 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 (PC R-RFLP) analysis of C8A was performed using the restriction enzyme Hha I. Distribution of the alleles was determined in pigs (n = 173) of se veral different breeds. Estimates of allele frequency of the 201 bp fr agment were 0.22,.0.43, .0.04, .0.50, .0.58, .0.50,.0.98 and 0.91 in L andrace, Large White, Duroc, Berkshire, Jinhua, Crown Miniature Pig, w ild boar, and Meishan, respectively.