Progressive coevolution of the yeast centromere and kinetochore

Area of Science:

• Genetics
• Evolutionary Biology
• Molecular Biology

Background:

• Centromere DNA and kinetochore complexes are crucial for accurate chromosome segregation during mitosis.
• Kinetochore proteins are highly conserved, yet centromeres evolve rapidly, showing significant variation.
• Understanding the evolution of new centromeres that interact with conserved kinetochores is a key question.

Purpose of the Study:

• To investigate how organisms evolve novel centromeres that maintain functional interactions with the kinetochore machinery.
• To identify and track centromere evolution across major fungal clades over extended evolutionary periods.

Main Methods:

• Analysis of thousands of centromeres from over 2,500 natural fungal isolates.
• Tracking centromere evolution across two major fungal clades, spanning more than 1 billion years of evolutionary history.

Main Results:

• New centromeres emerge and propagate through a combination of genetic drift and natural selection.
• The kinetochore complex, evolving at a slower pace, acts as a selective filter, determining the viability of new centromere variants.
• Demonstrated the progressive spread and fixation of novel centromeres within fungal populations.

Conclusions:

• Centromere evolution is shaped by interplay between rapid centromere innovation and the constraints imposed by the conserved kinetochore.
• The findings offer insights into the evolutionary mechanisms and constraints governing centromere diversification.
• Provides a framework for understanding how rapidly evolving genomic regions can be integrated into essential cellular processes.