The germline genome of the binucleated ciliate Tetrahymena thermophila undergoes programmed chromosome breakage and massive DNA elimination to generate the somatic genome. Here we present a complete sequence assembly of the germline genome and analyze multiple features of its structure and its relationship to the somatic genome, shedding light on the mechanisms of genome rearrangement as well as the evolutionary history of this remarkable germline/soma differentiation. Our results strengthen the notion that a complex, dynamic, and ongoing interplay between mobile DNA elements and the host genome have shaped Tetrahymena chromosome structure, locally and globally. Non-standard outcomes of rearrangement events, including the generation of short-lived somatic chromosomes and excision of DNA interrupting protein-coding regions, may represent novel forms of developmental gene regulation. We also compare Tetrahymena's germline/soma differentiation to that of other characterized ciliates, illustrating the wide diversity of adaptations that have occurred within this phylum.
Micronuclear Genome AssemblyPublicly available at NCBI Nucleotide (accession no: AFSS00000000).
Tetrahymena thermophila SB210 micronuclear genome sequencingPublicly available at NCBI BioProject (accession no: PRJNA51571).
Macronuclear Genome AssemblyPublicly available at NCBI Nucleotide (accession no: AAGF03000000).
Tetrahymena thermophila Transcriptome SequencingPublicly available at NCBI BioProject (accession no: PRJNA177770).
- Chad Nusbaum
- Robert S Coyne
- Wei Miao
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
- Kathleen Collins, University of California, Berkeley, United States
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