Cosegregation of asymmetric features during cell division

Area of Science:

• Cell Biology
• Genetics
• Evolutionary Biology

Background:

• Cellular asymmetry is crucial for multicellular organism aging and evolution.
• The mechanisms by which cells differentiate 'old' from 'new' components remain largely unexplored.
• It is unclear if this capability is limited to specialized cells or is a fundamental cellular trait.

Purpose of the Study:

• To investigate the segregation of old and new DNA, spindle pole body (SPB), and cell ends in the unicellular eukaryote *Schizosaccharomyces pombe*.
• To determine if asymmetric segregation is an inherent feature of even simple unicellular organisms.

Main Methods:

• Utilized *Schizosaccharomyces pombe* as a model unicellular eukaryote.
• Tracked the segregation of three distinct asymmetric features: parental DNA strands, spindle pole body (SPB), and cell ends.
• Analyzed the distribution of these components during cell division.

Main Results:

• Chromosome I, containing the new parental DNA strand, preferentially segregated to daughter cells inheriting the old cell end.
• The newly formed SPB also showed preferential segregation to the daughter cells receiving the old cell end.
• Demonstrated a non-random distribution of asymmetric cellular components.

Conclusions:

• The ability to distinguish between 'old' and 'new' cellular components is an inherent feature of unicellular eukaryotes.
• Asymmetric DNA segregation is a fundamental process, not exclusive to highly specialized cells.
• Findings provide insights into the evolutionary origins of cellular asymmetry.