The Y chromosome, the last part of the complete human genome, has been deciphered

For years, the human Y chromosome, one of the two sex chromosomes, has been sequenced because of its complex structure. Now a team of more than a hundred scientists has succeeded in deciphering it, which is an important step in discovering its real role in development, fertility or cancer.

The complete sequence of a chromosome related to male development was the last missing piece in the map of the human genome, and its details are presented in two articles. in the journal Nature.

Behind this achievement is the T2T (Telomere to Telomere) consortium, the same one that in 2022 published the first complete sequence of the human genome in six articles in the journal Science and a dozen additional papers in other publications.

This near-complete map—which lacked a definitive “photograph” of the Y chromosome—completed the milestone reached two decades ago when nearly 92% of the human genome was mapped, already marking a revolution in biology and science. Medicine.

In 2022, data from the remaining 8% were provided, revealing hidden regions important for understanding genetic diseases, reproduction or human diversity. The papers published today in Nature come full circle.

Now that the complete sequence of the Y chromosome has been achieved, “the complete set of human chromosomes is finally complete,” explained a statement from the National Human Genome Research Institute (NHGRI), which is leading the research.

The Y chromosome, along with the X chromosome, is often the subject of debate about its role in sexual development. Although these chromosomes play a central role, the factors involved in human sexual development are scattered throughout the genome and are highly complex, resulting in the wide variety of human sexual characteristics found in males, females, and intersex individuals. , detailed by NHGRI and Johns. Hopkins University.

These categories are not equivalent to gender, recall these institutes, adding that recent work shows that genes on the Y chromosome contribute to other aspects of human biology, such as cancer risk and severity.

The Y chromosome has been particularly difficult to decipher because of its repetitive molecular patterns; Assembling your sequence data is like reading a long book cut into pieces.

New sequencing technology and bioinformatics algorithms allowed researchers to unravel this DNA sequence.

The new data fills in gaps in more than 50% of this chromosome and reveals important genomic features that influence fertility, for example, factors involved in sperm production.

When scientists and doctors study an individual’s genome, they compare their DNA to the DNA of a reference standard to determine where the variations are, the University of California writes.

“Great Lagoons”

Until now, the Y chromosome portion of the genome contained “big gaps,” making it difficult to understand the variations and associated diseases.

“When variations are discovered that haven’t been seen before, the hope is always that these genomic variants are important for understanding human health,” said Adam Filippi, a consortium leader and NHGRI researcher.

For the researcher, medically relevant genomic variants can help develop better diagnostics in the future.

The genome is an organism’s complete set of instructions, a book written by combinations of only four chemical units designated A, T, C, and G (adenine, thymine, cytosine, and guanine); They are called nucleotide bases.

For humans, this instruction manual contains about 3 billion base pairs (or letters) found on the 23 pairs of chromosomes inside the nucleus of every cell. Sequencing means determining your exact sequence in a segment of DNA.

The final sequence of the Y chromosome adds 30 million new bases to the reference to the human genome, summarize those responsible. These databases reveal the presence of another 41 genes that activate proteins, providing crucial information for those studying reproduction or evolution.

A complete map of the male chromosome is published in an article in Nature. The second reports the sequencing of 43 diverse human Y chromosomes representing 21 different populations. The collections take a closer look at genetic variation over 183,000 years of human evolution, revealing new DNA sequences, signatures of conserved regions, and molecular mechanisms that contribute to the complex structure of the Y chromosome.

Source: El Diario





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