Marine parasite survives without key genes

A team from Germany, Egypt, France, Canada, the United Kingdom and the Czech Republic sequenced the parasite’s complete genome to find it had virtually no genes in its mitochondria.  

The finding can help better understand the evolutionary history of dinoflagellates and their relatives such as the malaria-causing parasite, says co-author Ahmed Moustafa, an associate professor of bioinformatics at the American University in Cairo, Egypt. 

Amazingly, the parasite had a drastically reduced number of genes in its plastid too, a cellular organelle that aids in photosynthesis, rendering it defunct. 

The plastid DNA in most dinoflagellates contains 14 genes. Amoebophrya ceratii has one remnant plastid gene. The reduction in genes in its mitochondria is even more striking. While some of its relatives contain at least three mitochondrial genes, the parasite has none.  

Amoebophrya ceratii needs energy when it forms a large number of dinospores, the free-floating stage of its life cycle that seeks out a new host to invade. The researchers say the parasites utilise specific genes in the cells’ nuclei to keep their mitochondria functional and producing energy.

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