Cloning of cDNA and amino acid sequence of one of chicken cone visual pigments

The chicken has four kinds of color visual pigments, in addition to rhodopsin. A chicken genomic DNA library was screened with cDNA of human red-sensitive pigment and a chicken genomic DNA fragment including rhodopsin exons 2, 3 and 4, and then a genomic DNA fragment encoding a visual pigment, possibly an iodopsin, was cloned. A cDNA library, constructed from chicken retina mRNA, was screened with the genomic DNA fragment and the cDNA of human red-sensitive pigment, and the cDNA encoding the pigment was cloned. The nucleotide sequence of this cDNA was similar to that of the human red-sensitive pigment, with identities of 78% for the nucleotide sequence and 84% for the amino acid sequence with human red-sensitive pigment.