AUTHOR=Yazaki Euki , Yabuki Akinori , Nishimura Yuki , Shiratori Takashi , Hashimoto Tetsuo , Inagaki Yuji 

TITLE=Microheliella maris possesses the most gene-rich mitochondrial genome in Diaphoretickes

JOURNAL=Frontiers in Ecology and Evolution

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/ecology-and-evolution/articles/10.3389/fevo.2022.1030570

DOI=10.3389/fevo.2022.1030570

ISSN=2296-701X

ABSTRACT=<p>The mitochondrial genomes are very diverse, but their evolutionary history is unclear due to the lack of efforts to sequence those of protists (unicellular eukaryotes), which cover a major part of the eukaryotic tree. Cryptista comprises cryptophytes, goniomonads, kathablepharids, and <italic>Palpitomonas bilix</italic>, and their mitochondrial genomes (mt-genomes) are characterized by various gene contents, particularly the presence/absence of an ancestral (bacterial) system for the cytochrome <italic>c</italic> maturation system. To shed light on mt-genome evolution in Cryptista, we report the complete mt-genome of <italic>Microheliella maris</italic>, which was recently revealed to branch at the root of Cryptista. The <italic>M. maris</italic> mt-genome was reconstructed as a circular mapping chromosome of 61.2 kbp with a pair of inverted repeats (12.9 kbp) and appeared to be the most gene-rich among the mt-genomes of the members of Diaphoretickes (a mega-scale eukaryotic assembly including Archaeplastida, Cryptista, Haptista, and SAR) studied so far, carrying 53 protein-coding genes. With this newly sequenced mt-genome, we inferred and discussed the evolution of the mt-genome in Cryptista and Diaphoretickes.</p>