The year was 2001 when genome researchers announced the successful sequencing of the entire human genome. With one exception: the male sex chromosome (Y chromosome) still offered resistance. It was only in the summer of 2023 that an international team with Austrian participation managed to capture all parts of its sequence and combine them into a complete chromosomal sequence. It was published in the magazine “Natureza”.
“The human Y chromosome was famous because it was difficult to sequence and assemble due to its frequently repeated sequence,” wrote researchers led by Adam Phillippy, from the National Institutes of Health (NIH) in Bethesda (USA), in the specialized publication. As a result, until recently, more than half of them were not included in the reference genome (genetic material).
“It’s like a puzzle game, where almost everyone first makes the corners, edges and pieces with distinct features, but no one likes putting together the uniform pieces of the sky and grassy areas,” said Austrian bioinformatician Fritz Sedlazeck in an interview to APA: “OY About 85 percent of the chromosome consists of pastes, that is, highly repetitive sequences (repeated notes).”
A team of more than 80 people has been working for more than a year to complete it. “We refined our computer algorithms, but we also tested a lot manually to see the best way to put the pieces together,” says Sedlazeck, who works at the Human Genome Sequencing Center at Baylor College of Medicine in Houston (USA).
The reward is that we now know the entire sequence from “telomere to telomere”, that is, from one end of the chromosome to the other. It comprises more than 62 million “letters” (base pairs) and contains 693 genes. “For example, they are important for sperm production,” explained the researcher. 110 of them were not previously known. Like the objects in a puzzle, they only became recognizable after the chromosome was assembled.
Service: https://dx.doi.org/10.1038/s41586-023-06457-y