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Human genome sequencing ushers in a new milestone!
The first complete gap-free sequence of the human genome, done collaboratively by nearly 100 scientists, filled the last 8 percent of the gap.
The latest issue of Science rarely published six papers in a special issue, and two other papers on research methods were listed on the Nature Method on the same day.
One of the authors, Evan Eichler, a professor at the University of Washington, said:
We have read new chapters in the Book of Life as never before.
Back in 2003, the Human Genome Project made history by sequencing 92 percent of human genes for the first time.
Today, the newly formed Telomere-to-Telomere Consortium (T2T Consortium) fills the last 8% of the vacancies, while correcting some of the previous mistakes, and will also go down in history.
△ Some members of the T2T Alliance
The newly identified 8% dna fragment contains important immune response genes that help humans adapt and fight off viral and bacterial infections and are valuable in predicting drug responses.
Adam Phillippy, one of the initiators of the alliance and the University of Maryland, believes that personal genome sequencing is expected to be widely available within 10 years, and the cost of personalized medicine will drop significantly.
In addition, some of the newly discovered genes make the human brain larger than other primate brains, which helps to further the mystery of human evolution.
Conquer the last 8%
The original human genome project was completed by nearly 2,000 scientists in 6 countries in 13 years, and the last 8% of the remaining 8% was difficult to break through by the sequencing technology at that time.
There are two reasons for this:
First, there are many fragments in the last 8% that are repetitive.
Scientists use puzzles to describe this difficulty. If there are many small pieces in the puzzle that are very similar, it is even more difficult to find the right position.
New sequencing methods developed in recent years, Oxford Nanopore and PacBio HiFi, can process longer pieces of DNA at once, as if the blocks of a puzzle become larger and the number of blocks becomes smaller.
Second, it is difficult to find human cells with only one set of DNA.
Normal cells have two sets of DNA at the same time, one from the father and one from the mother, and the two sets of DNA are mixed together when sequencing makes it more difficult.
The solution this time is to use a set of cells from a "mole," a rare pregnancy disorder that causes embryonic cells to grow abnormally, retaining only one set of DNA.
Using the new method, the sequencing of 3.055 billion base pairs in human DNA sequences was finally completed.
Robert Waterston, former head of the Human Genome Project, commented on the new approach:
[The human genome] no longer has any hidden or unknown parts.
The new human reference genome is named T2T-CHM13, and future personalized gene sequencing can be used as a benchmark to target diseased genes, prevent and treat them in advance.
The results of the study were published a few months ago on the bioprint platform and are now officially published in Science.
Specific to the published content, there is still a little deficiency:
The molar cells used retain the XX chromosome, which is missing the Y chromosome.
However, scientists did not idle during this time, and the sequencing of the Y chromosome was actually completed separately.
Project leader Adam Phillippy announced the news on social media, and the sequencing of 24 chromosome genes in the human body has been completed.
The complete data of the latest reference sequence T2T-CHM13 v2.0 and an online browser are available for use by research teams worldwide.
The latest preprint of the paper containing the results of Y chromosome sequencing is scheduled to be released next month.
Address of thesis:
https://www.science.org/toc/science/376/6588
CHM13 v2.0 related data and tools
https://genomeinformatics.github.io/CHM13v2/