Shorthorn, 24 Belgian Blue crosses, 4 Charolais, and 10 each of Holstein, Murray Grey, and White ... et al. 1998).IntroductionFig 1. The seven transmembrane α-helix structure of a G protein-coupled ... receptor. source : http://en.wikipedia.org/wiki/G_protein-coupled_receptor1235674MC1R(Melanocortin-1