Organellar Genome Evolution

My recent and upcoming publications on mitochondrial and chloroplast genomes demonstrate previously unknown variation in organellar genome structure and content and provide insights into the evolutionary processes that shape these genomes. For example, we found evidence for numerous architectural rearrangements even among genomes of close relatives, previously unknown intron diversity, and in one case even the usage of an unprecedented stop codon (Fučíková et al. 2014).

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By showing corresponding blocks of genes in the same color, the diagram allows us to compare the gene order among genomes.

The upper portion of the diagram shows mitochondrial genomes of two algal species that have very different gene orders, implying that several structural genomic rearrangements occurred in their evolutionary history.

The bottom portion shows two different species, which have an identical gene order in their mitochondrial genomes.

More recently, we have discovered an unusual three-chromosome chloroplast genome in a peculiar freshwater alga Koshicola spirodelophila (Watanabe et al. 2016) and a currently ongoing honors thesis by Melissa Taylor documents another such arrangement in a yet-unnamed desert alga.

There is still a lot to be learned about the diversity of algal organellar genomes and studying them is a great opportunity to learn a variety of bioinformatic methods!

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