 "Gia" expression only occurs in the aorta and is presently the only gene known in "Drosophila" with a strictly aortic expression.This gene is also known as Mthl5 (methuselah-like G protein coupled receptor) and is part of a gene family found in insects but not vertebrates.Overexpression of "Gia" in a transgenic fly model did not cause any cardiac defects.