Distribution of allelic frequencies of SNPs and EAV-HP in SLCO1B3 in several blue-shelled and non-blue-shelled breeds.

aBoth homozygous and heterozygous hens in these populations lay blue-shelled eggs. Dongxiang and Lushi blue-shelled chickens are from China and Araucana chickens are from South America.bEAV-HP is the only one mutation showing complete association with blue eggshell phenotype. The “+” sign indicates that EAV-HP insertion is positive, while the “−” sign indicates no EAV-HP.cAll detected blue-shelled chickens carry EAV-HP insertion and the frequency of “+” allele is not equal to 1 in blue-shelled groups because some birds are heterozygotes (+/−).