Ancestral Eukaryotes Reproduced Asexually, Facilitated by Polyploidy: A Hypothesis.

Area of Science:

• Evolutionary Biology
• Molecular Genetics
• Protistology

Background:

• The ancestral state of eukaryotic reproduction (sexual vs. asexual) is debated.
• Discovery of meiosis-specific genes in protists suggests potential sexual activity.
• Asexual reproduction's potential for deleterious mutation accumulation is a key evolutionary concern.

Purpose of the Study:

• To re-evaluate the ancestral reproductive mode in eukaryotes.
• To investigate the function of meiosis-specific genes in protists.
• To explore alternative explanations for meiosis-specific gene expression in asexual lineages.

Main Methods:

• Genomic analysis of protist genomes for meiosis-specific genes.
• Review of existing literature on reproduction, polyploidy, and mutation accumulation.
• Functional analysis of gene expression in protist cultures.

Main Results:

• Meiosis-specific genes may have roles in polyploidy control and homologous recombination.
• These functions can occur independently of sexual reproduction (meiosis).
• Expression of these genes is observed in protist cultures without apparent cell fusion.

Conclusions:

• The presence of meiosis-specific genes does not necessitate sexual reproduction in protists.
• Polyploidy can mitigate mutation accumulation, supporting asexual reproduction as a viable strategy.
• Asexual reproduction, not sexual reproduction, is proposed as the ancestral condition for eukaryotes.