The yellow locus in Drosophila is involved in both cuticle development and 
behaviour. However, the function of the encoded protein is unknown. Here we have 
characterised the sequence and expression pattern of a new Drosophila gene, 
designated yellow-B, encoding a 453-amino-acid protein that is 57% identical to 
Yellow. High levels of yellow-B mRNA are present in the larval-pupal stages, but 
the gene is also expressed in the head. Bioinformatics analysis indicates that 
the Drosophila genome encodes at least 7 members of the Yellow family 
distributed among chromosomes 2, 3, and X. The Yellow proteins are related to 
the Royal Jelly proteins and have no relatives in other non-insect metazoan 
species. Interestingly, a Yellow-like protein is encoded by the genome of a 
radiation tolerant bacterium, Deinococcus radiodurans.