Scientists found that DNA once dismissed as “junk” helps chromosomes find their partners

Repetitive DNA near chromosome centers forms a unique barcode for partner recognition.

This barcode guides chromosomes to their correct partners during egg cell development.

When this DNA barcode is disrupted, chromosomes pair incorrectly or fail to pair.

A quality-control system eliminates eggs with such errors before they mature.

This discovery revives an old idea about "junk" DNA's role in reproduction.