Original title: who is responsible for the world's shortest group of Peruvians?
Now, a team studying the genetic characteristics of Peruvians (one of the shortest people in the world) has found a genetic variation that can shorten people's height by more than 2 cm on average. Peruvians are one of the shortest people in the world, and a gene mutation may explain why.
Hundreds of genes affect a person's height, but most of the differences are imperceptible, maybe only a few millimeters. Now, a team studying the genetic characteristics of Peruvians, one of the world's shortest people, has found a genetic variation that can shorten a person's height by more than two centimeters on average. 'it's amazing that they can see this change. 'Emma Farley, a geneticist at the University of California, San Diego, said:' it's a pretty big impact. '
Geneticists have been diligently searching for the genes that affect height. In 2014, an analysis called giant surveyed 250000 people. 'it's exciting that people can still find new players. 'Elaine Ostrander, a geneticist at the National Institute of human genome in Maryland, said:' this illustrates the value of studying isolated populations. 'so far, the mutation has not been found outside Peru, but it provides clues about how other mutations affect height. In Peru, the need to live at high altitudes may have driven the evolution of this mutation.
Samira Asgari and soumya raychaudhuri, both postdoctoral students from Harvard Medical School, initially wanted to know how a person's DNA affects the severity of tuberculosis. In collaboration with Megan Murray, an epidemiologist at the health partners foundation in Lima, they collected genetic information and other data, including height, from 4002 local residents. Peruvians are one of the shortest people in the world, with an average height of 165 cm for men and 153 cm for women. Peruvian men and women are about 10 cm and 15 cm shorter than the average person in the two countries, respectively, compared with Americans and Dutch, who are usually considered the tallest in the world. To this end, the team decided to search DNA data to find the genetic factors behind short stature.
First, Asgari compared the subjects' DNA with the genomes of Africans, Europeans and Native Americans to assess their lives. She reported at a recent conference on genomics biology in Cold Spring Harbor, New York that Peruvians have about 80%, 16% and 3% Native American, European and African ancestry respectively. 'the more Native American they have, the shorter they will be. 'Asgari said. By associating a variation in the Native American part of each person's genome with their height, Asgari found a specific genetic variation that appears to affect this trait.
The short Peruvians have an allele in the FBN1 gene. Compared with the normal DNA sequence of the gene, it has a different base. This small change changes the amino acids in a carbohydrate coated protein called fibrillin-1. The protein provides structural support for connective tissue. Previous studies have confirmed that other FBN1 mutations affect the height of patients with rare diseases: Marfan syndrome affects bones, heart and eyes, and often leads to height and weight loss; short stature is the hallmark of skin stiffness syndrome, with very thick and hard skin. Farley believes that the new link between the gene and overall height 'logically links unique biological phenomena'.
Of about 700 other genes related to height, most of them have little effect alone, and together they can only explain about 7% of a Peruvian's height. According to the researchers' estimation, the newly discovered allele alone accounts for another 1%. Asgari reported that a person carrying only one copy of the FBN1 mutation would be about 2.2 cm shorter than a person with a different version of the gene. At the same time, people with two copies of the mutation would be about 4cm shorter.
The team estimates that 5% of Peruvians carry the newly discovered FBN1 allele. This suggests that in Peruvians, evolution has resulted in short stature and thick skin. Many people live at high altitudes, and animal studies have shown that species living at these altitudes tend to be smaller. This is an obvious evolutionary adaptation to the scarcity of food in such places. At the same time, thick skin may protect the body from strong ultraviolet rays at high altitude.
However, kousik Kundu, a geneticist at the Sanger Institute of the Wellcome foundation in the UK, is skeptical about the role of the mutation. He suggested that Asgari get more detailed sequencing data from Peruvian subjects and study a larger population there.
Asgari also wants to study other short people, such as those in the Middle East, to see if the same allele is also at work there. Sarah Tishkoff, a geneticist at the University of Pennsylvania, said that with further genetic analysis, Asgari might be able to determine when the mutation that causes short stature occurred.