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The Highly Reduced and Fragmented Mitochondrial Genome of the Early-branching Dinoflagellate Oxyrrhis marina Shares Characteristics with both Apicomplexan and Dinoflagellate Mitochondrial Genomes (Slamovits et al., 2007)

This is an article about the genome of the Dinoflagellate Oxyrrhis with a small genome. Keeling’s group keeps referring to it as reduced, but that only holds if the endosymbiotic theory is correct. The problem is that the entire article is based (biased) on this, which makes it difficult to assess its real value. What is interesting is that there are organisms with mitochondria that only have a few genes, in this case only 2 (!), which is more in line with a gradual acquisition of genes than an enormous loss. You have to realize that these mitochondria are under almost complete control of the eukaryotic genome.

Specifically, Oxyrrhis has the smallest gene complement known, with several rRNA fragments and only two protein coding genes, cox1 and a cob-cox3 fusion.

…the two most highly represented clusters corresponded to mitochondrial genes: cox1 was the most abundant transcript with 339 ESTs assembling into a contig of 1589 bp in length, and a cob-cox3 fusion was the second most abundant transcript with 130 ESTs assembling into a contig of 2104 bp in length. We manually searched for other potentially mitochondrion-encoded protein- coding genes but found none; this is consistent with the protein–gene complements of both apicomplexans and dinoflagellates.

The rest is speculation and its assumes massive gene transfer, massive gene fragmentation, acquisition of RNA editing, all like they are one-step process. Not my type of science. I keep on wondering how this type of unfounded speculations can become mainstream science. It is a pity that the title is already biased. It should read “The Highly Reduced and Fragmented Mitochondrial Genome of the Early-branching Dinoflagellate Oxyrrhis marina Shares Characteristics with both Apicomplexan and Dinoflagellate Mitochondrial Genomes.

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