The rRNA of chloroplasts is more similar in base sequence to RNA from certain photosynthetic eubacteria than to rRNA in eukaryotic cytoplasm. Mitochondrial rRNA also has a base sequence which supports a eubacterial origin. The origins of mitosis and meiosis which also utilize microtubules. Mitosis made it possible for large eukaryotic genomes to be reproduced. Meiosis is essential to sexual reproduction.
Protists have the most varied sexual life histories of the eukaryotes.