An international research team has generated the first truly complete sequence of a human Y chromosome, the final human chromosome to be fully sequenced. The new sequence, which fills in gaps across more than 50% of the Y chromosome’s length, uncovers important genomic features with implications for fertility, such as factors in sperm production. The study, led by the Telomere-to-Telomere (T2T) Consortium, a team of researchers funded by the National Human Genome Research Institute (NHGRI), part of the National Institutes of Health, will published today (August 23) in the journal Nature.

When researchers completed the first human genome sequence 20 years ago, gaps were left in the sequences of all 24 chromosomes. However, unlike the small gaps sprinkled across the rest of the genome sequence — gaps that the T2T Consortium filled in last year — over half of the Y chromosome’s sequence remained a mystery.

All chromosomes have some repetitive regions, but the Y chromosome is unusually repetitive, making its sequence particularly difficult to complete. To tackle the most repetitive pieces of the human genome, the T2T Consortium applied new DNA sequencing technologies and sequence assembly methods, as well as knowledge gained from generating the first gapless sequences for the other 23 human chromosomes.

Now that the Y chromosome is fully sequenced, scientists will be able to include it in genomewide association studies, which are used to study the relationship between genes, traits and disease. The researchers can also more precisely analyze these deletions and their effects on sperm production.

“When you find variation that you haven’t seen before, the hope is always that those genomic variants will be important for understanding human health,” said Adam Phillippy, Ph.D., a senior investigator at NHGRI and leader of the consortium. “Medically relevant genomic variants can help us design better diagnostics in the future.”

According to scitechdaily.com