By Chris Skeldon 
The X and Y chromosomes, known as the sex chromosomes, determine an individual’s biological sex – Photo by Jonathan Bailey, National Human Genome Research Institute, National Institutes of Health
Scientists have taken an important step toward understanding the human genome by deciphering the mysterious Y chromosome found in men, a feat that could help guide research on male infertility.
👶🔎 On Wednesday 8/23 Researchers have revealed the first complete sequence of the Y chromosome Human, which is one of the two sex chromosomes – the X chromosome is the other – and is usually passed from father to son. It is the last of the 24 chromosomes – filamentous structures that carry genetic information from cell to cell – in the human genome to be sequenced.
We humans have a pair of sex chromosomes in each cell. Men have one Y chromosome and one X chromosome, while women have two X chromosomes, with a few exceptions.
🧬👨 🔬 the Y chromosome genes help control reproductive functions are crucial, including the production of sperm, which is formally called spermatogenesis, and is even involved in the risk and severity of cancer. But this chromosome has proven difficult to decipher due to its exceptionally complex structure.
“I attribute this to new sequencing techniques and computational methods,” said Arang Rai, a scientist at the US National Human Genome Research Institute and lead author of a paper explaining the achievement in the journal Nature.
Geneticist Karen Mega in the lab at the University of California, USA – Photo: Carolyn Lagatota, University of California, Santa Cruz/Handout via Reuters
“This finally gives us our first complete look at the Y chromosome code, revealing more than 50% of the chromosome length that was missing from our genomic maps,” said Karen Mega, a professor of biomolecular engineering at UCLA. Santa Cruz (UCSC) and co-author of the study, and co-leader of the Telomere-to-Telomere Consortium behind the research.
🔬📖 The complete sequence of the X chromosome was published in 2020. But until now, the Y chromosome portion of the human genome had large gaps. The work revealed features of medically relevant regions of the Y chromosome, including a stretch of DNA containing several genes involved in sperm production.
The researchers said the new and more complete understanding of the genes of the Y chromosome bodes well for practical applications, including fertility research.
Many of these genes are important for fertility and reproduction, especially spermatogenesis. Therefore, being able to catalog normal changes, as well as cases where azoospermia (the absence of sperm in the semen) occurs, could be useful for IVF clinics, as well as for future research on the activity of these genes.
– Monica Czeskova, co-author and postdoctoral fellow in biomolecular engineering at the University of California, San Francisco
In addition to identifying some additional genes on the Y chromosome, the researchers found that a portion of the chromosome’s DNA had been mistakenly assumed to be of bacterial origin in previous studies.
You Scientists continue to expand our understanding of human genetics. The first map of the human genome was revealed in 2003.
The first complete human genome — albeit containing only part of the Y chromosome — was published last year. In May, researchers published a new version of the genome that improved on its predecessor by including a wider variety of people to better reflect the world’s population of 8 billion.
*With information from Will Dunham, Reuters