After more than two decades human genome project Celebrated as a scientific milestone, scientists finally got the job done. The first complete, gap-free human genome sequence has been published in a breakthrough that hopes to pave the way for new insights into health and what makes our species unique.
Dr Karen Mega, a scientist at the University of California, Santa Cruz who co-leads the international consortium behind the project, said: “These parts of the human genome that we haven’t been able to study for more than 20 years are important to study. our understanding of how the genome functions, genetic disease, human diversity, and evolution.”
To date, about 8% of the human genome has been lost, including large highly repetitive sequences, sometimes described as ‘junk DNA’. Although, in fact, this recurring section was omitted due to technical difficulties in the sequence, not just a lack of interest.
Sequencing the genome is something like breaking a book into chunks of text and then trying to rebuild the book by putting it back together. Text extensions that contain a lot of common or repetitive words and phrases can be more difficult to place than unique sections of text. New “length-read” sequencing technologies that decode large chunks of DNA at once – enough to capture multiple repetitions – have helped overcome this hurdle.
The scientists were able to simplify the puzzle further by using an unusual type of cell containing only DNA inherited from the father (most cells in the body contain two genomes – one from each parent). Together, these two advances enable the decoding of the more than 3 billion letters that make up the human genome.
“In the future, when a person’s genome is sequenced, we will be able to identify all the variants in their DNA and use that information to better guide healthcare,” said Dr. Adam Philippi, of the National Human Genome Research Institute in Maryland and co-chair of the coalition. “Really completing the sequencing of the human genome is like putting on new glasses. Now that we can see everything clearly, we are one step closer to understanding what it all means.”
One area of interest is that the parts of the genome that contain a lot of repetitive stretches are among the most diverse in human genetics. Variations within this region can also provide important clues about how our human ancestors underwent rapid evolutionary changes that led to more complex cognition.
This work is also likely to lead to a better understanding of the mysterious component of the genome known as the centromere. They are dense bundles of DNA that bind chromosomes together and play a role in cell division, but until now they were considered unplanned because they contain thousands of repeating sequences of DNA sequences.
The science behind the sequencing effort and some preliminary analyzes of new genomic regions is outlined in six research papers published in the journal to know.
“When we opened up this new section of the genome, we thought there would be genetic diversity that contributes to many different traits and disease risk,” said Rajiv McCoy, of Johns Hopkins University and co-author of the telomere-to-telomere (T2T) consortium. “There are aspects like, ‘We don’t know yet what we don’t know.’”
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