Abstract
Abstract
Background
The Cyanidiophyceae is an early-diverged red algal class that thrives in extreme conditions around acidic hot springs. Although this lineage has been highlighted as a model for understanding the biology of extremophilic eukaryotes, little is known about the molecular evolution of their mitochondrial genomes (mitogenomes).
Results
To fill this knowledge gap, we sequenced five mitogenomes from representative clades of Cyanidiophyceae and identified two major groups, here referred to as Galdieria-type (G-type) and Cyanidium-type (C-type). G-type mitogenomes exhibit the following three features: (i) reduction in genome size and gene inventory, (ii) evolution of unique protein properties including charge, hydropathy, stability, amino acid composition, and protein size, and (iii) distinctive GC-content and skewness of nucleotides. Based on GC-skew-associated characteristics, we postulate that unidirectional DNA replication may have resulted in the rapid evolution of G-type mitogenomes.
Conclusions
The high divergence of G-type mitogenomes was likely driven by natural selection in the multiple extreme environments that Galdieria species inhabit combined with their highly flexible heterotrophic metabolism. We speculate that the interplay between mitogenome divergence and adaptation may help explain the dominance of Galdieria species in diverse extreme habitats.
Funder
Ministry of Oceans and Fisheries
Rural Development Administration
National Research Foundation of Korea
NIFA-USDA
Publisher
Springer Science and Business Media LLC
Subject
Ecology, Evolution, Behavior and Systematics
Cited by
14 articles.
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