To arrive at their findings, researchers from the United States and Europe analyzed the genomes of more than 35,000 people. If there were average height differences for individuals with certain genetic variants, this indicated that something in that genomic region containing the variants likely influenced height. In this particular study, researchers initially examined the effects of more than 2 million genetic variants.
The new variant accounts for less than 1 percent of the genetic basis of height, and is associated with an average difference in height of about 0.4 centimeters, or a little more than an eighth of an inch. The range went from 0.3 cm to 1.4 cm, depending on the population and whether an individual had one or two copies of the so-called taller version of the variant. A variety of factors, including genetics, diet and prenatal environment, interact to determine how tall someone grows. It is currently thought that genetic factors are responsible for at least 80 percent of the variation in height among people.
The variants most strongly associated with height lie in a region of the human genome thought to influence expression of a gene for growth differentiation factor 5, called GDF5, which is a protein involved in the development of cartilage in the legs and other long bones. Rare variants in the GDF5 gene have been associated with disorders of skeletal development, and more common variants recently have been tied to susceptibility to osteoarthritis of the hip and knees in Asian and European populations.
The completion of the map of human genetic variation, or HapMap, has fueled a surge in this type of genome-wide association study, with most of the growth coming in the past 10 months. Researchers around the globe have now associated more than 60 common DNA variants with the risk of more than 20 common diseases or related traits.
|Contact: Laura Bailey|
University of Michigan