Over 4cm of men's height is due to the combination of just two genes, according to a new study undertaken at the University of Melbourne.The research, published in the Journal of Clinical Endocrinology and Metabolism this week, identifies one gene on chromosome 15 and one on the Y chromosome as contributors to height in men. These genes may also help explain why men are taller than women.
"If you have the tall version of both of these genes you will be taller than a person who only has the tall version of one of them," the author said.
The Y chromosome is the male sex chromosome, absent in women. The gene on chromosome 15, called CYP19, codes for aromatase - an enzyme that converts testosterone into oestrogen in both sexes. Oestrogen influences height because it is responsible for bones fusing over at the ends, which stops people growing.
A person's height depends on both genetic and environmental influences. Previous studies have identified the aromatase gene and the Y chromosome gene as height genes in men who are very tall or very short, but the Melbourne study shows they also help determine normal adult height in the general population.