Mutation rate: up to a nucleotide per generation

The frequency of occurrence of gene mutations in humans has been determinedDmitry Safin, Compulenta

In 1935, one of the founders of modern genetics, John Burdon Sanderson Haldane, gave his estimate of the frequency of occurrence of gene mutations in humans, based on the results of studying many cases of hemophilia; from the calculations of the biologist it followed that for every 25 million nucleotides of the genome there should be one mutation. In the future, this figure was clarified by studying various genes and comparing human and chimpanzee DNA.

The authors of the work in question proved that the first indirect estimates were surprisingly accurate: each of us, as it turned out, carries 100-200 mutations, which corresponds to the appearance of one mutation per 15-30 million nucleotides.

To conduct the study, experts chose a family that had lived in a Chinese village for several centuries. The objects of the study were sections of the Y chromosome of two distant male relatives, who were separated by 13 generations, and whose common ancestor lived 200 years ago. Sequencing was performed using modern techniques on Illumina equipment; out of 10,149,085 analyzed letters of the genetic code, 10,149,073 matched. After conducting an additional analysis of twelve detected differences, the authors found out that eight of them were the result of cell cultivation in the laboratory, and only four mutations could be considered natural.

The occurrence of mutations in the studied example.
The sequenced chromosomes are highlighted in red.
Each mutation corresponds to a lightning symbol of its own color;
as it is easy to see, the exact moments of occurrence of most mutations could not be determined.

"It turns out that for every 30 million nucleotides in one generation, there is one mutation," concludes study coordinator Chris Tyler—Smith from the Sanger Institute (UK). — These are exactly the numbers we expected; this is encouraging, since no one has used the advanced sequencing technology we used in such studies before. Now that we have a technique for accurately estimating the frequency of mutations, we can determine its values in various regions of the genome and find out how people differ from each other in this parameter."

The full version of the scientists' report will be published in the journal Current Biology.

Prepared based on the materials of the Sanger Institute.

Portal "Eternal youth" http://vechnayamolodost.ru28.08.2009