About 20 years ago, two competing research groups participated in an amazing race 92 percent From the human genome decoded. The projects are considered milestones in biomedical research.
For the first time, it was possible to understand which genetic building blocks control the functions of our bodies – and thus research more precisely what happens to diseases, for example. But eight percent of the genetic sequence was missing. An international team now wants to fill this gap largely with the help of new technology.
Accordingly, the number of DNA bases recorded in his analyzes increased from 2.92 billion to 3.05 billion, which corresponds to an increase of 4.5 percent. The number of registered genes, that is, the blueprints on which cells produce proteins, increased by only 0.4 percent to 1969. However, newly identified regions can reveal how cells activate or disrupt the activation of individual genes.
Official confirmation missing
However, the work has some weaknesses. The cell line used did not come from a fully developed human. data So far only uploaded to a prepress server, no evaluation by independent researchers.
“You’re trying to get to the last unknown thing in the human genome,” said Karen Mega, a researcher at the University of California, Santa Cruz who was part of the project. Medical news site “Statnews”. The areas examined now have not been analyzed before because this is a complex matter.
The new study is made possible because new sequencing techniques no longer break genetic material into small pieces and put it back together again. This technique works for large parts of the genome, but not in regions where the same pattern is repeated multiple times. The sequence of rules can no longer be reconstructed.
A crucial region for cell division
The eight percent of the human genome that has yet to be decoded consists of such repetitive sequences that are difficult to analyze. They are located in the nodes that hold chromosomes together – called centromeres. Structures play an important role in cell division, for example in fetal development.
To analyze the missing areas, the international team combined two alternative techniques. In one, a DNA molecule is pulled through a small hole and large pieces of it are arranged in one piece. The other uses a laser to check DNA sequences multiple times. Both methods are more expensive than the previously created technique and are not yet reliable, but together they provide a beneficial result.
George Church, a famous molecular biologist and genome researcher from Harvard university, he explained, according to “Stat News” that so far he indicated in his lectures that no one has sequenced the complete genome of vertebrates until today. If the results of the new work are confirmed, then this comment is invalid.
The DNA sequence was not from a human
In their analysis, Mega’s team examined only 23 of the 46 chromosomes that a human cell normally contains. The cell line analyzed came from a so-called bubble mole, which is created when an egg cell without a nucleus is fertilized by a sperm. Then the cell contains only the genetic material of the father, and the other half is missing. In this way, the research team was able to reduce the computing power required for analysis.
The first sequence of the human genome also contained only 23 chromosomes. At the time, the Human Genome Project (HGP) and Celera Inc. had genomes from the aspiring genetic pioneer. Craig Winter Almost the entire human genome was analyzed for the first time.
In February 2001 they published the details Her first work in a specialized magazine. Accordingly, they deciphered 83 percent of the genome, and further analyzes brought the value up to 92 percent.
However, as technology advances, practitioners now tend to examine all 46 chromosomes. The team surrounding study director Megan wants to try that in the next step.
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