Haplotype blocks at Hbb-b1. (A) The high allele contributing strains from crosses in which Chcmq3 was detected are all hemoglobin diffuse and the low allele strains hemoglobin single. Lowercase indicates imputed loci. Asterisks indicate resequenced SNPs. (B) Resequencing of SNP rs52263982 in strains 129S1/SvImJ and DBA2 confirms they carry the C allele.