Half a centimeter mutation

Just one DNA building block can increase a person's height

A person's height is largely determined by his heredity. This is such a commonplace that neither experts nor ordinary people doubt it. However, until now scientists are practically unaware of the genes that are responsible for whether a person grows two meters tall or is short. Typically, specialists study the genetic factors associated with certain diseases. And growth is no exception: close attention to a DNA error is warranted if, for example, this error leads to dwarfism. But a height of 170 or 180 cm is normal, and such variations, apparently, are not of particular interest for practical science.

But recently, as Physorg.com reports, scientists have discovered a gene that slightly affects human height. And this happened more or less by accident. Initially, Exeter Medical School and the University of Oxford studied the influence of heredity on the incidence of type 2 diabetes. Thanks to this, they obtained a solid database of genetic data on 5 thousand people, where, naturally, such trivial information as the height and weight of volunteers was mentioned. And after that, the researchers noticed small differences in a gene called HMGA2. In some cases, instead of the usual “building block” of thymine, this part of the DNA contained cytosine. This minimal change was enough: one copy of the mutated gene was enough to add half a centimeter to a person’s average height. Two copies give an increase of a whole centimeter. Later, these data were checked on other genetic databases; in total, almost 35 thousand people were covered in Britain, America, Finland, and Poland.

The discovery looks, of course, somewhat funny: what is 5-10 mm when the height of healthy people differs by tens of centimeters? But no one said that HMGA2 alone is responsible for human anthropometric data. Apparently, height is influenced by several genetic factors. And not only genetic ones, but much more banal ones, like good nutrition in childhood. Let's say that modern acceleration apparently arose without any influence of DNA, it was just that living standards rose sharply in the 20th century, and people followed them. Scientists note that the cytosine variation of the HMGA2 gene is responsible for only 0.3% of the manifestations of “tallness.” The remaining 99.7% must be found in other parts of our DNA.

By the way, this gene only works seriously for a few months in our lives. It turns on in the early stages of embryo development, does what it is supposed to do, and then - shortly before birth - safely “falls asleep.” One of the results of its action is a slight increase in the length of the spine and limbs. Apparently, the work of HMGA2 is not limited to this, and it also affects other systems of our body. For example, it is noted that this gene is associated with the occurrence of certain malignant tumors.

Vladimir DZAGUTO