Stunted Peruvians
Scientists have found the most powerful growth gene of all known
Sofia Jabotinskaya, Naked Science
An international team of researchers who studied the genetic diversity of the inhabitants of Peru, said that they were able to detect the strongest genetic factor influencing growth. An article about the discovery was published in Nature (Asgari et al., A positively selected FBN1 missense variant reduces height in Peruvian individuals).
One of the variants of the FBN1 gene encoding the fibrillin protein turned out to be such a factor. This variant, designated as E1297G, was found exclusively among the indigenous inhabitants of the region (Indians) and was significantly associated with the low growth of the carrier.
Micrographs of fibrillin in the tissues of Peruvian Indian women. A drawing from an article in Nature.
Each copy of E1297G was associated with a decrease in height by an average of 2.2 centimeters. People with two copies of such a gene were on average 4.4 centimeters shorter than those who did not have this variant in their genome. This effect is much more powerful than the influence exerted by other identified variants of genes that are somehow related to growth: however, a copy of the gene usually gives an effect measured in a few millimeters.
"This study clearly shows the advantage of studying different population groups and having a diverse worldwide strategy for human genome research," says senior author of the study Soumya Raichaudhuri. "Our findings also have implications for FBN1–related diseases."
It has long been known that a wide range of mutations in the FBN1 gene is directly related to Marfan syndrome, a connective tissue pathology that manifests itself in relatively high growth with a slim build, as well as joint hypermobility and problems with the cardiovascular system. However, the E1297G variant is in no way related to Marfan syndrome.
The newly discovered variant is noticeably more common in coastal populations of Peruvian Indians living near the Pacific Ocean. This suggests that low growth may be the result of adaptation to environmental factors. Interestingly, E1297G is found in the genomes of about five percent of the indigenous inhabitants of Peru, but less than one percent of Mexican Indians. In the genome of people of European origin, there is no variant at all.
"One of the most important conclusions of this study was that genetic variants of the same gene can have very different effects," says co–author Samira Askari. – Previously, if you asked a geneticist what a variant of this gene affects, they would probably answer what causes the disease. But we found something completely different."
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