Do funny dumb hair dues and wearing high heels make you look taller? Scientists have known for more than a century that this is hereditary. Common people have known it since ever.

But now an international team at the Broad Institute of Harvard and MIT, Children's Hospital Boston, the University of Oxford and Peninsula Medical School, Exeter, has found the first gene whose variation is linked to height variation in humans.

The team looked inside the genome of 35,000 people for single letter differences in the DNA that were found more often in tall individuals than in shorter ones. The scientists detected a difference in the HMGA2 gene, a 'C' replacing 'T' in the DNA code. The 'C' gene variant made people taller: one copy added 0.5 cm in height while two copies about 1 cm.

"This is the first convincing result that explains how DNA can affect normal variation in human height," said senior author Joel Hirschhorn, an associate member of the Broad Institute, a pediatric endocrinologist at Children's Hospital Boston and an associate professor of genetics at Harvard Medical School.

"Because height is a complex trait, involving a variety of genetic and non-genetic factors, it can teach us valuable lessons about the genetic framework of other complex traits - such as diabetes, cancer and other common human diseases."

Short stature by itself is not a health problem, but delayed growth in children is a symptom of severe general health issues.
"By defining the genes that normally affect stature, we might someday be able to better reassure parents that their child's height is within the range predicted by DNA, rather than a consequence of disease," said Hirschhorn.

90% of our height variation is linked to DNA, while the rest is the result of lifestyle factors, life condition and food. By now, the geneticists have analysed just rare, single-gene mutation affecting height, but not common in the general population.

The first 5,000 DNA analyses came from the subjects of two diabetes researches; a second phase of analysis was made on 30,000 individuals, adults and children, from US, England, Finland and Poland.

Still, the 'C'-'T' variation represents only 0.3% of the normal variability in human height, thus many others height related genes have to be discovered, in studies involving larger pools of subjects.

"Unlike most other complex traits, height is something that can be easily defined and measured in very large numbers of people. Soon the scientific community will have access to many more large-scale genomic data sets, making it feasible to identify additional genes involved in height." said Hirschhorn.

The HMGA2 is active in the first months of fetal growth and is deactivated before birth, therefore growth is controlled early in human development. The gene affects the final length of both the limbs and spine in young children. HMGA2 has also been connected to some types of cancer. In the end, cancer is just an abnormal growth.