A tall story? Genes do manipulate height

April 7th, 2008 - 11:17 am ICT by admin  

A file-photo of Peninsula Medical School

New York, April 7 (IANS) Scientists now have a far clearer picture of what makes some people tall - and others not so. Researchers who last year identified the first gene influencing height have now identified a further 20 regions of the genome which, together, can make a difference of up to six centimetres in a person’s height.

The results, based on DNA samples of 30,000 people, and published Sunday with two independent studies in the journal Nature Genetics, implies that scientists now know of dozens of genetic regions that influence our height.

This provides scientists with a fascinating insight into how the body grows and develops normally and may shed light on diseases such as osteoarthritis and cancer.

Unlike a number of other body size characteristics such as obesity, caused by a mix of genetic and environmental factors, 90 percent of normal variation in human height is due to genetic factors rather than, for example, diet.

Last year, a team including Tim Frayling from the Peninsula Medical School, Exeter, and Mark McCarthy of Oxford, identified the first common gene variant to affect height, though it made a difference of only 0.5 cm.

“The number and variety of genetic regions that we have found show that height is not just caused by a few genes operating in the long bones,” said Frayling.

On the basis of DNA samples, researchers have identified 20 regions of genetic code, common variations of which influence adult height.

Half of these regions contain genes whose functions are well documented. Other genes have a role in cell-to-cell signalling, an important process in the early development of embryos in the womb.

One region in particular is also linked to osteoarthritis, the most common form of arthritis.

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