| Autor: |
Singh M; Max Planck Institute for Biology, Tuebingen, 72072 Germany., Seah BKB; Max Planck Institute for Biology, Tuebingen, 72072 Germany., Emmerich C; Max Planck Institute for Biology, Tuebingen, 72072 Germany., Singh A; Max Planck Institute for Biology, Tuebingen, 72072 Germany., Woehle C; Max Planck Genome Center Cologne, Max Planck Institute for Plant Breeding, Cologne, 50829 Germany., Huettel B; Max Planck Genome Center Cologne, Max Planck Institute for Plant Breeding, Cologne, 50829 Germany., Byerly A; Department of Computer Science and Information Systems, Bradley University, Peoria, IL 61625., Stover NA; Department of Biology, Bradley University, Peoria, IL 61625., Sugiura M; Department of Chemistry, Biology, and Environmental Sciences, Faculty of Science, Nara Women's University, Nara, 630-8506 Japan., Harumoto T; Department of Chemistry, Biology, and Environmental Sciences, Faculty of Science, Nara Women's University, Nara, 630-8506 Japan., Swart EC; Max Planck Institute for Biology, Tuebingen, 72072 Germany. |
| Abstrakt: |
Massive DNA excision occurs regularly in ciliates, ubiquitous microbial eukaryotes with somatic and germline nuclei in the same cell. Tens of thousands of internally eliminated sequences (IESs) scattered throughout the ciliate germline genome are deleted during the development of the streamlined somatic genome. The genus Blepharisma represents one of the two high-level ciliate clades (subphylum Postciliodesmatophora) and, unusually, has dual pathways of somatic nuclear and genome development. This makes it ideal for investigating the functioning and evolution of these processes. Here we report the somatic genome assembly of Blepharisma stoltei strain ATCC 30299 (41 Mbp), arranged as numerous telomere-capped minichromosomal isoforms. This genome encodes eight PiggyBac transposase homologs no longer harbored by transposons . All appear subject to purifying selection, but just one, the putative IES excisase, has a complete catalytic triad. We hypothesize that PiggyBac homologs were ancestral excisases that enabled the evolution of extensive natural genome editing. |
