Myxozoans are a large group of poorly characterized cnidarian parasites. To gain further insight into their evolution, we sequenced the mitochondrial (mt) genome of Enteromyxum leei and reevaluate the mt genome structure of Kudoa iwatai. Although the typical animal mt genome is a compact, 13–25 kb, circular chromosome, the mt genome of E. leei was found to be fragmented into eight circular chromosomes of ~23 kb, making it the largest described animal mt genome. Each chromosome was found to harbor a large noncoding region (~15 kb), nearly identical between chromosomes. The protein coding genes show an unusually high rate of sequence evolution and possess little similarity to their cnidarian homologs. Only five protein coding genes could be identified and no tRNA genes. Surprisingly, the mt genome of K. iwatai was also found to be composed of two chromosomes. These observations confirm the remarkable plasticity of myxozoan mt genomes.
Bibliographical noteFunding Information:
We would like to thank Naomi Paz for editing the text, Dennis Lavrov for suggesting to search for the MRPP3 gene, the associate editor and four anonymous reviewers for their helpful comments and suggestions. This work was supported by the Israel Science Foundation 663/10 to D.H.
© The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved.
- gene conversion
- tRNA loss
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Molecular Biology