Molecular genetic analysis of genes encoding the heavy chains of rabbit IgG

We analyzed the genes which encode the heavy chain constant region of rabbit IgG molecules. Five DNA clones derived from the chromosomal region which spans the C gamma coding sequences were isolated from a recombinant phage library of rabbit liver DNA. Four of these clones can be grouped together by overlaps; together they represent 37 kb of genomic DNA, and contain one C gamma gene and one tentatively identified C epsilon gene. A second C gamma gene was identified which did not overlap with the group of four clones because of restriction site differences found in the flanking regions 5' to the C gamma genes. Nucleotide sequences of the two C gamma genes were identical. Comparisons of the restriction maps of the two cloned C gamma genomic regions suggest that they may represent allelic regions of chromosomes of two different heavy chain haplotypes with polymorphisms in the regions flanking the C gamma genes.