A conserved architectural domain shapes centromere evolution in Drosophila

Area of Science:

• Genetics
• Molecular Biology
• Genomics

Background:

• Centromeres are crucial for chromosome segregation during cell division.
• Centromeres are paradoxically located in rapidly evolving repetitive DNA regions.
• The histone variant CENP-A defines centromere identity, but its maintenance amid DNA turnover is poorly understood.

Purpose of the Study:

• To investigate how conserved centromere function is maintained despite rapid evolution of surrounding DNA.
• To resolve centromere structure and its relationship with pericentromeric DNA in *Drosophila melanogaster*.
• To understand the role of higher-order chromatin organization in centromere stability.

Main Methods:

• Generation of highly contiguous genome assemblies from single *Drosophila melanogaster* individuals.
• Comparative genome assembly analysis across wild-derived strains.
• Integration of Hi-C interaction maps with DNA sequence analysis.

Main Results:

• Resolved a complete chromosome, including its centromere, in *Drosophila melanogaster*.
• Identified extensive structural variation in pericentromeric satellite DNA (e.g., *dodeca* and *Prodsat*) across different strains.
• Demonstrated conserved organization of the CENP-A-associated centromeric core.
• Showed that flanking *dodeca* satellite arrays form a conserved, spatially interacting domain bridging the centromere.

Conclusions:

• Conserved higher-order chromatin architecture, particularly the *dodeca* satellite domain, constrains rapidly evolving centromeric DNA.
• This conserved architecture provides a framework for reconciling the rapid sequence evolution of centromeres with their essential, conserved function.
• The study offers insights into the centromere paradox and mechanisms of genome stability.