Would you expect the plastid DNA of photosynthetic dinoflagellates, diatoms, and golden algae to be more similar to the nuclear DNA of plants (domain Eukarya) or to the chromosomal DNA of cyanobacteria (domain Bacteria)? Explain.

The organisms of the biological world are classified under three distinct domains; two of them are prokaryotic (domain Bacteria and domain Archaea), and the third one is eukaryotic (domain Eukarya).

The prokaryotic domains only have unicellular organisms, while the eukaryotic domain comprises both multicellular and unicellular members.

The cell of eukaryotic organisms comprises several membranous structures (organelles), each with a distinct function. Plastids are the membranous organelle found within the eukaryotes that can photosynthesize. Plastid structures comprise different pigments and are also the centre for food storage.

The most well-accepted hypothesis related to the origin of plastids is the endosymbiotic theory.As per this hypothesis, plastids are developed by the modification of cyanobacteria (a photosynthetic bacteria) which was engulfed within a eukaryotic cell.

Since plastids are considered to be formed from cyanobacteria, the plastid DNA would more likely resemble the genome of prokaryotic cyanobacteria rather than resembling the genome of plants.