How can the DNA recovery system replicate chromosomes?

Researchers at Duke University Medical Center and the National Institute of Environmental Health (NIEHS) have recently discovered possible chromosomal fractures. How to bind together to transform chromosomes and how to create new species.

Lucas Argueso - a scholar from Duke University's Department of Microbiology and Molecular Genetics - said: 'People have discovered many high-level structures that are repeated in the genomes of most hierarchical animals. High and make hypotheses that explain why so many segments are repeated like that. We have been able to demonstrate in yeast that repeated sequences allow new chromosome type formation (called chromosome aberration). This is also an important path to genome diversity '.

Scientists used X-rays to break down the enzyme's chromosome structure, then studied how the lesions were restored. Most chromosomal detection errors are formed from the interaction between repeating DNA sequences located on different chromosomes rather than just a simple combination of broken ends. a chromosome.

Chromosomal errors are mutations on the complementary chromosome normally due to deletion, segmentation or inversion . In rare cases, the formation of one of these new chromosome structures is beneficial, but most DNA alterations are harmful, leading to problems such as oncology.

Argueso said: 'Any reorganization can be beneficial. These differences may be more useful in natural selection, even helping to form new species'.

The error of radioactivity in yeast was originally discovered by co-author Jim Westmoreland of NIEHS Molecular Genetics Laboratory, Duke's Argueso made meticulous molecular analysis.

Researchers have discovered how chromosomal fractures can bind together to alter chromosomes while simultaneously generating new species.(Photo: iStockphoto / Andrey Volodin)

For the yeast used in the study, the repeating DNA sequence accounts for about 3% of the chromosome. In higher animals like humans, about half of the genome contains repetitive fragments 'forming human weakness'. 'If broken at the repeated part, it is not only one chromosome that has been repaired, but all similar repeating structures in many other locations in the genome are also restored.'

The sequencing of many different people has brought a surprising number of structural variations among individuals, according to Thomas D. Petes, president of the University's Department of Microbiology and Molecular Genetics. Duke and co-author of yeast research. He said: 'We look forward to observing the transformation, losing or adding a base pair. Nobody thinks someone can have two copies of a gene, while others have one or even three copies of the same gene . ' Human studies also show that many of the re-sorting phenomena found in humans occur in locations where the DNA fragment is repeated. This can happen thanks to a mechanism similar to that found in yeast.

According to Petes, yeast studies may be related to cancer studies . He said: 'Most solid tumors have high levels of rearrangements, as well as excess chromosomes. The combination of repetitive genes is clearly a path for reorganizing sections, although some reorganization sections are also formed by other paths. This is an evolutionary battle between normal cells and tumor cells. A pathway that helps tumor cells escape the growth regulation of normal cells is to change its genome. '

The study was published online on August 13 in the Proceedings of the National Academy of Sciences in collaboration with author Michael A. Resnick of the Molecular Genetics Laboratory at NIEHS. Funding for the research was provided by the National Institutes of Health and from the internal research fund of the National Institute of Environmental Health Sciences. Other authors of the study are Piotr A. Mieczkowski and Malgorzata Gawel of Duke's Department of Microbiology and Molecular Genetics.