Sequence analysis of C3H/HeJ showed that this polymorphic variant has point mutations relative to the b variant that result in valine instead of isoleucine at amino acid 9, leucine instead of glutamine at amino acid 52, and isoleucine instead of phenylalanine at amino acid 71, all within the amino terminal scavenger receptor cysteine-rich D1 domain, in addition to 7 silent point mutations. This allele is found in many inbred strains including CBA/J, C3H and DBA substrains.