Chromeraceae

Chromeraceae

The Chromeraceae is a family of single-celled, photosynthetic organisms that belong to the phylum Apicomplexa. This family is notable for its unique evolutionary position and its implications for understanding the evolution of photosynthesis in eukaryotes. Members of the Chromeraceae family are closely related to the Apicomplexa, a group that includes important parasites such as Plasmodium, the causative agent of malaria.

Characteristics

Chromeraceae are characterized by their ability to perform photosynthesis, a trait that is unusual among the Apicomplexa. The family includes the genera Chromera and Vitrella, both of which possess plastids that are capable of photosynthesis. These plastids are believed to be derived from a red algal ancestor, similar to the plastids found in dinoflagellates and diatoms.

The cells of Chromeraceae are typically spherical and possess a single flagellum. They have a complex life cycle that includes both sexual and asexual reproduction. The presence of photosynthetic plastids suggests that these organisms may have once been free-living algae before becoming more closely associated with their apicomplexan relatives.

Evolutionary Significance

The discovery of Chromeraceae has provided significant insights into the evolution of photosynthesis in eukaryotes. The presence of photosynthetic plastids in Chromeraceae supports the hypothesis that the common ancestor of apicomplexans and dinoflagellates was photosynthetic. This suggests that the loss of photosynthesis in most apicomplexans was a secondary event, likely associated with their transition to a parasitic lifestyle.

The study of Chromeraceae also helps to elucidate the evolutionary history of plastids, which are thought to have originated from a single endosymbiotic event involving a cyanobacterium. The plastids of Chromeraceae are surrounded by four membranes, indicating a complex history of secondary endosymbiosis.

Ecological Role

Chromeraceae are primarily found in marine environments, where they are thought to play a role in the symbiotic relationships with corals. Chromera velia, for example, has been isolated from the tissues of scleractinian corals, suggesting a potential role in coral health and resilience.

Also see

• Apicomplexa
• Photosynthesis
• Plastid
• Endosymbiotic theory
• Dinoflagellate

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