Ninety percent of the variation in heights is due to genes and DNA, not the nutrition

Want to know if your baby will be tall or short? Perhaps you should consult a hedgehog. In a trawl through the human genome, scientists have netted a cluster of key genes that influence height, and some of the DNA nuggets are genes that control lyrically-named proteins called sonic hedgehog, Indian hedgehog and desert hedgehog. The study by British scientists, published on Sunday in the journal Nature Genetics, entailed sifting through samples from more than 30,000 people of European descent to look for common variations in the genetic code that help determine height. The sleuths found 20 new regions, or loci, of the genome that, put together, can make a difference in height of up to six centimetres (2.4 inches). Unlike obesity, which is driven by genetic and environmental factors, height is almost entirely a genetic affair. Ninety percent of normal variation in human height can be attributed to one's DNA heritage rather than nutrition.


The 20 loci account for roughly three percent of this 90 percent. Last September, the same team found a genetic variant that accounted for another 0.3 percent. Some of the 20 genes spotted in the new probe are well known and their function has been intensively explored. They include genes, such as the hedgehogs, that are essential for cell division, a finding that may be useful for cancer research. Some genes act as switches, which turn other genes on and off. And others play a role in cell-to-cell signalling. But roughly half of the genes are a completely unknown quantity. "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" of the body, said Tim Frayling of the Peninsula Medical School in Exeter, southwestern England. "Instead, our research implicates genes that could shed light on a whole range of important biological processes. "By identifying which genes affect normal growth, we can begin to understand the processes that lead to abnormal growth -- not just height disorders but also tumour growth, for example." Taller people are statistically likelier to be at risk from some kinds of cancer (prostate, bladder and lung, for instance), while short people seem to be more prone to heart disease. via AFP.

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