Since 2005, they have compared and analyzed the genome sequences of human, chimpanzee, rhesus monkey, mouse, fruit fly, rice and Saccharomyces cerevisiae through bioinformatics technology. It is found that the insertion/deletion (Indel) of DNA will cause a series of variations around it. On this basis, they put forward "Indel-induced spontaneous mutation mechanism hypothesis", which answered the basic question "how genetic variation is formed" from the source.
Gene mutation mainly refers to the change of nucleotide sequence, species and quantity in DNA. Mutation can be divided into spontaneous mutation and induced mutation. For a long time, the classical understanding of spontaneous mutation mechanism in academic circles is that spontaneous mutation is random and rare. However, with the breakthrough of DNA sequencing technology since 1990s, researchers have accurately estimated the number and distribution of spontaneous mutations in the genome, and generally believe that "spontaneous mutations are not randomly distributed in the genome, and mutation hotspots generally exist in the genome". This conclusion poses a great challenge to the traditional understanding of randomness and rarity of spontaneous mutation, and the world scientific community has not found a universal mechanism to explain this important scientific problem so far.
The new mechanism of gene mutation discovered by Professor Tian Dacheng successfully solved this suspense: First, the mutation rate in different regions of the genome varies greatly, and the number of spontaneous mutations is determined by the number and density of Indels, and the number of spontaneous mutations near Indels is not uncommon. However, Indel itself is a point mutation, and its occurrence is random, so the mutation induced by Indel is also random. Secondly, the origin of most spontaneous mutations was found, that is, the original source of biodiversity variation was mainly induced by Indel; Thirdly, natural selection is realized to a great extent through the selection of Indel, and the spontaneous mutation rate is also the result of natural selection to a great extent; Fourth, the ability of organisms to adapt to the environment by adjusting their own mutation ability is much greater than people originally thought, which means that mutation plays a huge role in evolution.
The research results not only answer a lot of scientific questions, but also have great potential application value in solving the mechanism of tumor and crop genetics and breeding.
Condra Schouw, a review expert of Nature magazine, wrote in his real-name evaluation of this paper: "This is a very interesting and enlightening discovery, which will arouse strong repercussions in the scientific community."
In the colorful life world, what makes life attractive diversity? After years of painstaking research, Professor Nanjing University boldly put forward the "inder Mutation Hypothesis" and solved many biological suspense with the newly discovered "universal mechanism of gene mutation". On July 20th, the latest issue of Nature, a top international magazine, introduced this project independently completed by NTU.