Salivary amylase

According to research by American scientists: In the long and long history of human development, salivary amylase is a good way to help human ancestors obtain more energy from starch, thereby accelerating the process of human evolution. This discovery is of great help in studying whether humans adapt to the surrounding environment and the relationship between genetic variation and human evolution.

Starch is also a good source of energy in this era of high material living standards. However, if there is insufficient amylase in human saliva, we will not be able to utilize this complex carbohydrate well, because the enzymes contained in other parts of the body cannot break down starch as well as salivary amylase.

Previous studies have found that some people have more copies of the gene for making salivary amylase than others, but the purpose of these extra copies has not been understood.

In the latest experiment, anthropologist George Perry of Arizona State University and his research team studied people with different numbers of amylase genes. They measured the amylase levels in the people's saliva and concluded from analysis that the extra copies produced more amylase, with an enhanced ability to break down starch.

The researchers then expanded the scope of the experiment and collected human saliva samples from Africa, Asia, Europe and the Arctic. The study found that ethnic groups whose food contained high starch content, such as the Hadza in Tanzania, tended to have more amylase genes, with an average of 6.7 copies; while ethnic groups whose food contained low starch content, such as the Mbuti in Central Africa, also had fewer amylase genes, with an average of 5.4 copies. In addition, chimpanzees, which mainly feed on fruit, have only two copies of the salivary amylase gene.

By comparing the genomes of humans and chimpanzees, Dominy believes that the increase in human salivary amylase genes began hundreds of thousands of years ago, which coincides with the emergence of agriculture (about 150,000 years ago). He speculated that the increase in this gene led to an increase in human brain capacity and promoted the development of intelligence. However, he also said that more complete genome sequences are needed from different cultural groups to determine the exact time when the amylase gene increased.

Biologists at the University of Colorado believe that related research like this will be popularized everywhere in the future. This study is a good demonstration, which allows us to understand the process of human evolution in a very vivid and appropriate way.