Y Chromosome: The Dark Matter of the Human Genome Unveiled.

This article focuses on the recent completion of the human Y chromosome sequence by the Telomere-to-Telomere (T2T) consortium, resolving its previously uncharacterized complex repetitive regions. Utilizing advanced sequencing technologies and assembly methods, the T2T consortium added approximately 30 million base pairs to the human reference genome, resulting in a fully assembled Y chromosome of over 62 million base pairs containing 693 genes, including 110 newly identified ones. The complete sequence clarifies the structure of clinically important regions such as the azoospermia factor (AZF) domains, which are critical for spermatogenesis and male fertility, and reveals chromosomal rearrangements affecting these functions. This comprehensive assembly is expected to enhance understanding of Y chromosome-related health issues, including fertility and cancer risks, and to support future genomic medicine research.