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2019-03-08 03:04:01

By Jonathan Knight in Denver ADULT height depends mostly on a single gene, say researchers in the US. They have shown that one gene accounts for 70 per cent of the height variation in humans. Unlike eye colour, height varies continuously across a wide range. So geneticists have long held that, given enough nutrition, a person will grow to a height determined by many genes. “That seems reasonable,” says Walter Nance of the Medical College of Virginia in Richmond. “But our data suggest that it is not the case.” Nance noticed that people with an abnormality that gives them three sex chromosomes, such as XXX or XYY, are unusually tall. So he turned his attention to phog, a gene that is known to influence height and is found on both sex chromosomes. He and his colleagues tested 140 pairs of non-identical twins and their parents to see which version of the gene each carried. Twins who had inherited the same version of the gene from their mother, as well as the same version from their father, were roughly the same height at the age of 15, whereas twins who shared the phog gene from only one parent were less likely to be the same height. Twins who had neither copy of phog in common were the most different in stature. Computer analysis of the twin data suggests that phog accounts for most of the height variation in the population studied, Nance says, and probably in the population at large. He adds that the protein product of the phog gene is thought to regulate other genes in bone cells. Because there was no height correlation to phog before twins reached puberty, the gene may be involved in controlling pubescent spurts in growth. Peter Tishler, a medical geneticist from Harvard Medical School in Boston, says that while twin studies often fail to take confounding variables into account, Nance’s work looks solid. “What he does is much more sophisticated,