Sequence homology: Cow: 100%; Dog: 100%; Goat: 79%; Guinea Pig: 93%; Horse: 93%; Human: 100%; Mouse: 100%; Pig: 100%; Rabbit: 100%; Rat: 100%; Sheep: 79%; Yeast: 100%; Zebrafish: 85%. Guanine nucleotide-binding proteins (G proteins) form a large family o