Geneticists are getting to the long and short of the genes that control how tall a person will grow. The short answer is that at least 180 different common genetic variants are involved; the long, that more than 600 variants may control human height.
Scanning the genetic blueprints of more than 100,000 people, scientists have turned up at least 180 different genetic variants involved in determining human height, the researchers report online September 29 in Nature. That may sound impressive, but each of the genes involved has a small effect, and researchers are still able to account for only about 10 percent of the genetic contributions that give rise to the wide variation in height.
“It’s a lot more complicated than we originally thought, and there may be thousands of variants with subtle effects,” says Michael Weedon, a geneticist at Peninsula College of Medicine & Dentistry in Exeter, England. Weedon is one of 293 coauthors of the new study, which reanalyzed data from more than 50 previous genome-wide association studies to find genes that affect growth in people.
Larger studies might uncover even more genetic variants associated with height. Assuming all variants have the same modest effects as the ones in this study — each affecting height by a millimeter or so — the researchers calculate that between 483 and 1,040 different variants may be involved, accounting for almost 20 percent of the genetic components that determine height. Scientists are still debating where the remaining genetic components are likely to be found.