T saidThe first human genome was listed in 2001 as part of the Human Genome Project, but researchers found it incomplete and inaccurate. Now, scientists have produced the most compiled human genome to date, filling in the gaps and correcting errors in the first power.
The sequence is the most complete reference genome for any mammal today. Information from six new papers describing the genome, published in Scienceshould lead to an in -depth understanding of human development or indicate new goals for the treatment of many diseases.
It is a very precise human genome
“The Human Genome Project relied on DNA obtained through blood drawings; that was the technology at the time,” said Adam Phillippy, head of genome informatics at the National Institutes of Health’s National Human Genome Research Institute ( NHGRI) and senior author of one of the new papers. “The technologies at that time added to the mistakes and gaps that have persisted over the years. It’s good now to fill those gaps and fix those gaps.”
“We always knew there were missing pieces, but I don’t think any of us appreciated how many of them, or how interested they were,” said Michael Schatz, a doctor of computer science and biology at Johns Hopkins. University and a senior author of it. paper.
The work is the result of the Telomere to Telomere consortium, supported by NHGRI and involving genetic and computational biology experts from a variety of industries around the world. The team looked to fill in 8% of the human genome left in a genetic black hole from the original process. Since then, geneticists have tried to reunite those missing parts. The most recent study group found that the entire chromosome value of new genes, revealing 200 million additional genetic groups (letters that make up the genome) and 1,956 new genes.
“From the Human Genome Project [in 2001], we have announced the victory several times in the last two years, ”said Evan Eichler, a professor of genome science at the University of Washington and a senior author of one of the papers. Eichler, who was also involved in the mapping of that basic process, said it was a different idea than what was being set up at the moment. “While the primary goal of the Human Genome Project is to command and organize any basic level cannot be achieved because there is not enough technology. So we finished as many pieces as we could. “
The promise of new information
Reconstituted fragments contain previously undetectable fragments such as centromeres, the middle fragments of chromosomes that hold the double long strands of DNA that are arranged when they are removed. cords, copy themselves and separate themselves into two chambers in one cell. division. These areas are important for normal human development and also play a role in brain development and neurodegenerative diseases. “It’s one of the great mysteries of biology found in all eukaryotes – plants, animals, people, trees, flowers and higher organisms – it’s centromeres. It’s a fragment. DNA reconstruction and chromosomes arrangement and cell division are very important, but it is a very good paradox, because even though its work has been around for billions of years, it is almost impossible. it can’t be taught because we don’t have a centromere sequence to monitor, ”Schatz said. “Now we’re done.”
Scientists have been able to trace the length of DNA obtained by new processes, which geneticists first thought were like copying and releasing what is called ” junk DNA “. These new processes, in turn, can play a role in some human diseases. “Just because the process is repetitive, it’s not rubbish,” Eichler said. He points out that important genes are embedded in these recorded territories – genes that help machines make proteins, genes that guide how they are distributed and differentiated. their DNA in their two daughter cells, as well as specific human genes that can differentiate human species. from our evolutionary relationship, primates. In one of the papers, for example, the researchers found that the numbers of primates of these recorded countries were different than that of humans, and that they were in different parts of the genome.
“This is one of the most important tasks of survival, and of making us human,” Eichler said. “Obviously, if you destroy these genes, you won’t survive. It’s not a bad thing for me.
Explaining the nature of these new segments, if any, and how the sequences of undetected areas such as centromeres translate to new drugs or to understand the disease humans, starting, said Deanna Church, vice president at Inscripta, a genome engineer. Professional who writes articles on scientific articles. Having the entire sequence of a human genome is different from extracting it; He thought that scientists had explained only half of how the human genome works.
A place for improvement. For half of humanity it’s a new process – that is, half of the genetic makeup is always found in a person’s DNA. Each person has two groups of chromosomes, mother and father. Each DNA strand contains different types of genes, which actually give us two genomes. Merging those two genomes was not a difficult task, and those problems hampered the first Human Genome Project and led to its disappearance. The processing technology at the time could not easily separate copies of maternal and paternal DNA, so if scientists tried to compare certain fragments with the assumption that they were working with the maternal chromosome , for example, they run to places where they can’t because. they actually interact with the parent chromosome. “It’s like having two piles in the same box,” Phillippy said. “You have to explain the differences and rebuild the two.”
For this new process, the scientists used a fertilization error where the embryo resulted in only adult chromosomes. The result of the growth of the first 2000 years that continued in the lab was removed as a cell line that continued despite its normal chromosomal structure. This makes it easier for groups to assemble the genome because they are actually working with a single genetic cluster to solve.
Finally, however, researchers need a complete human genome with complete sequences of maternal and paternal chromosomes. Coming soon. Phillippy and others are working with trios of DNA samples from volunteers and their mothers and fathers so that scientists can separate maternal DNA from paternal ones. and combine two separate genomes. The teams expect the so -called diploid human genome sequence to be completed by the end of the year.
Now, says Winston Timp, a professor of biomedical technology at Johns Hopkins and an author on one of the papers, “the new genome team is paying for the fragments because it provides a map. It’s more accurate to understand the data we get from the mind. ”It involves finding new ways to differentiate healthy people from those who are sick, for example, and different ways that people are more likely to develop certain diseases.
“We’ve seen millions of undiscovered genetic traits before the samples of thousands of people whose genomes have been pre -arranged,” said Rajiv McCoy, assistant professor of biology at Johns Hopkins. and another author. “We’ll have to wait until the next work to learn more about their association with the disease, but the main focus of the work now is to try to identify the genetic factors. new things never seen before. “
Even with the full extent of the human genome, scientists may not say that it will change the old power, despite its flaws and flaws. That’s because there are more years of working on human genetics than ever before – like the difference between your favorite copy of a book, and your handwritten notes and signature on the pages, as well as a new copy from the bookstore. . “A genome is as good as it shows,” Eichler said. “All medical clinics and researchers have built up a decade of data on the ancient genome that is full of gaps. It’s horrible to repeat that work for every lab. He thinks that many labs are slowly changing the way they work with the new genome by comparing small amounts of data before running an experiment to see how much more valuable and comprehensive the information they produce and from the new genome. Like the real human genome, the new material has been put in a public library for scientists to use. “At this time, both genomes will be preserved so there is no substitute. , “he said.
In the coming years, researchers will begin to recreate the complete genome, using maternal and paternal DNA, to help scientists identify the best targets for new medicine and improve understanding of human growth and development. The more genomes they have, the more important features that can lead to new knowledge of human disease and new therapies for them. Ultimately, the goal is for individuals to be able to distinguish their entire genome as part of their medical history, so that physicians can compare those processes to indicators. and determine the various conditions relating to specific diseases.
“This represents the world with a new chromosome that we never saw before,” said Karen Miga, associate professor of biomolecular engineering at the University of California, Santa Cruz and senior author. of some of the papers. “We have new lands, new processes and the right time and the promise of new information.”
Happiness is seen in genomics and the healthy community. “Hallelujah, we’ve eliminated one human genome, but the best is yet to come,” Eichler said shortly. “Nobody knows this will happen, but it’s the beginning of a change not only in genomic research but in medicine as well.”
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