Sterkiella histriomuscorum, formerly Oxytricha trifallax, is a ciliate species in the genus Sterkiella, known for its highly fragmented genomes which have been used as a model for ciliate genetics.
Like all ciliates, O. trifallax has two different types of nuclei: macronuclei, which are the site of transcription and gene expression, and micronuclei, which are only active during sexual reproduction but are otherwise transcriptionally inactive. Macronuclei are formed by the differentiation of micronuclei, which usually involves some degree of RNA-mediated DNA editing. O. trifallax is the first species sequenced with an unusually high degree of fragmentation in its macronuclear genome. Up to 96% of the micronuclear genome is eliminated during the differentiation into a macronucleus; in comparison, in other ciliates like Paramecium only about 30% is eliminated. The macronuclear genome has a haploid size of about 50 Mbp.[2]
The chromosomes of the macronucleus are also unusually short. The macronuclear genome encodes about 18,500 genes, but these are distributed on 16,000 chromosomes, which are called nanochromosomes due to their length.[2][3] Because of their unusually short nanochromosomes, most of which contain only a single gene, they have been used as a model organism to study telomeres and to screen for non-coding RNA genes.[4]
The micronuclear genome has also been sequenced, and contains about 3,500 scrambled genes. Scrambled genes are genes whose individual segments are located in different parts of the micronuclear genome, and therefore have to be "unscrambled" during the DNA editing step into a conventional gene in the macronuclear genome. More than 225,000 individual DNA segments have to be unscrambled during the development of a macronuclear genome from its micronuclear precursor.[5]
The mitochondrial genome has also been sequenced, and is the largest known ciliate mitochondrial genome, with a length of about 70 kbp. Like other ciliate mitochondrial genomes, those of O. trifallax are linear molecules and contain a number of split genes. Their mitochondria also possess a separate plasmid, which may have been involved in horizontal gene transfer during the evolution of the mitochondrial genome.[6]
Taxonomy and systematicsedit
The taxonomy of O. trifallax has been contested. It was reclassified as Sterkiella histriomuscorum on the basis of morphological characteristics, but a molecular phylogeny supports the original classification as a species of Oxytricha.[7]
Referencesedit
^Warren, A. (2019). World Ciliophora Database. Sterkiella histriomuscorum (Foissner, Blatterer, Berger & Kohmann, 1991) Foissner, Blatterer, Berger & Kohmann, 1991. Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=427777 on 2019-01-07
^"This Bizarre Organism Builds Itself a New Genome Every Time It Has Sex". WIRED. Retrieved 2017-07-25.
^Jung, S.; Swart, E. C.; Minx, P. J.; Magrini, V.; Mardis, E. R.; Landweber, L. F.; Eddy, S. R. (2011-09-01). "Exploiting Oxytricha trifallax nanochromosomes to screen for non-coding RNA genes". Nucleic Acids Research. 39 (17): 7529–7547. doi:10.1093/nar/gkr501. ISSN 0305-1048. PMC3177221. PMID 21715380.
^Chen, Xiao; Bracht, John R.; Goldman, Aaron David; Dolzhenko, Egor; Clay, Derek M.; Swart, Estienne C.; Perlman, David H.; Doak, Thomas G.; Stuart, Andrew (2014). "The Architecture of a Scrambled Genome Reveals Massive Levels of Genomic Rearrangement during Development". Cell. 158 (5): 1187–1198. doi:10.1016/j.cell.2014.07.034. PMC4199391. PMID 25171416.
^Swart, Estienne C.; Nowacki, Mariusz; Shum, Justine; Stiles, Heather; Higgins, Brian P.; Doak, Thomas G.; Schotanus, Klaas; Magrini, Vincent J.; Minx, Patrick (2012-01-01). "The Oxytricha trifallax Mitochondrial Genome". Genome Biology and Evolution. 4 (2): 136–154. doi:10.1093/gbe/evr136. PMC3318907. PMID 22179582.
^Zoller, Stephen D.; Hammersmith, Robert L.; Swart, Estienne C.; Higgins, Brian P.; Doak, Thomas G.; Herrick, Glenn; Landweber, Laura F. (2012). "Characterization and Taxonomic Validity of the Ciliate Oxytricha trifallax (Class Spirotrichea) Based on Multiple Gene Sequences: Limitations in Identifying Genera Solely by Morphology". Protist. 163 (4): 643–657. doi:10.1016/j.protis.2011.12.006. PMC3433844. PMID 22325790.
Other resourcesedit
"OxyDB | Oxytricha Genome Database Wiki".
"In one of nature's innovations, a single cell smashes and rebuilds its own genome".
January 01, 1970
sterkiella, histriomuscorum, formerly, oxytricha, trifallax, ciliate, species, genus, sterkiella, known, highly, fragmented, genomes, which, have, been, used, model, ciliate, genetics, scientific, classification, domain, eukaryota, clade, diaphoretickes, clade. Sterkiella histriomuscorum formerly Oxytricha trifallax is a ciliate species in the genus Sterkiella known for its highly fragmented genomes which have been used as a model for ciliate genetics Sterkiella histriomuscorum Scientific classification Domain Eukaryota Clade Diaphoretickes Clade SAR Clade Alveolata Phylum Ciliophora Class Spirotrichea Family Oxytrichidae Genus Sterkiella Species S histriomuscorum Binomial name Sterkiella histriomuscorum Foissner Blatterer Berger amp Kohmann 1991 Foissner Blatterer Berger amp Kohmann 1991 Synonyms 1 Histriculus muscorum Kahl 1932 Corliss 1960 Histrio macrostoma Gellert amp Tamas 1958 Histrio muscorum Kahl 1932 Opisthotricha terrestris Horvath 1956 Oxytricha histrioides Gellert 1957 Oxytricha histriomuscorum Foissner Blatterer Berger amp Kohmann 1991 Oxytricha terrestris Horwath 1958 Dragesco amp Dragesco Kerneis 1986 Oxytricha trifallax Greslin Prescott Oka Loukin amp Chappell 1989 Contents 1 Genetics 2 Taxonomy and systematics 3 References 3 1 Other resourcesGenetics editLike all ciliates O trifallax has two different types of nuclei macronuclei which are the site of transcription and gene expression and micronuclei which are only active during sexual reproduction but are otherwise transcriptionally inactive Macronuclei are formed by the differentiation of micronuclei which usually involves some degree of RNA mediated DNA editing O trifallax is the first species sequenced with an unusually high degree of fragmentation in its macronuclear genome Up to 96 of the micronuclear genome is eliminated during the differentiation into a macronucleus in comparison in other ciliates like Paramecium only about 30 is eliminated The macronuclear genome has a haploid size of about 50 Mbp 2 The chromosomes of the macronucleus are also unusually short The macronuclear genome encodes about 18 500 genes but these are distributed on 16 000 chromosomes which are called nanochromosomes due to their length 2 3 Because of their unusually short nanochromosomes most of which contain only a single gene they have been used as a model organism to study telomeres and to screen for non coding RNA genes 4 The micronuclear genome has also been sequenced and contains about 3 500 scrambled genes Scrambled genes are genes whose individual segments are located in different parts of the micronuclear genome and therefore have to be unscrambled during the DNA editing step into a conventional gene in the macronuclear genome More than 225 000 individual DNA segments have to be unscrambled during the development of a macronuclear genome from its micronuclear precursor 5 The mitochondrial genome has also been sequenced and is the largest known ciliate mitochondrial genome with a length of about 70 kbp Like other ciliate mitochondrial genomes those of O trifallax are linear molecules and contain a number of split genes Their mitochondria also possess a separate plasmid which may have been involved in horizontal gene transfer during the evolution of the mitochondrial genome 6 Taxonomy and systematics editThe taxonomy of O trifallax has been contested It was reclassified as Sterkiella histriomuscorum on the basis of morphological characteristics but a molecular phylogeny supports the original classification as a species of Oxytricha 7 References edit Warren A 2019 World Ciliophora Database Sterkiella histriomuscorum Foissner Blatterer Berger amp Kohmann 1991 Foissner Blatterer Berger amp Kohmann 1991 Accessed through World Register of Marine Species at http www marinespecies org aphia php p taxdetails amp id 427777 on 2019 01 07 a b Swart Estienne C Bracht John R Magrini Vincent Minx Patrick Chen Xiao Zhou Yi Khurana Jaspreet S Goldman Aaron D Nowacki Mariusz 2013 01 29 The Oxytricha trifallax Macronuclear Genome A Complex Eukaryotic Genome with 16 000 Tiny Chromosomes PLOS Biology 11 1 e1001473 doi 10 1371 journal pbio 1001473 ISSN 1545 7885 PMC 3558436 PMID 23382650 This Bizarre Organism Builds Itself a New Genome Every Time It Has Sex WIRED Retrieved 2017 07 25 Jung S Swart E C Minx P J Magrini V Mardis E R Landweber L F Eddy S R 2011 09 01 Exploiting Oxytricha trifallax nanochromosomes to screen for non coding RNA genes Nucleic Acids Research 39 17 7529 7547 doi 10 1093 nar gkr501 ISSN 0305 1048 PMC 3177221 PMID 21715380 Chen Xiao Bracht John R Goldman Aaron David Dolzhenko Egor Clay Derek M Swart Estienne C Perlman David H Doak Thomas G Stuart Andrew 2014 The Architecture of a Scrambled Genome Reveals Massive Levels of Genomic Rearrangement during Development Cell 158 5 1187 1198 doi 10 1016 j cell 2014 07 034 PMC 4199391 PMID 25171416 Swart Estienne C Nowacki Mariusz Shum Justine Stiles Heather Higgins Brian P Doak Thomas G Schotanus Klaas Magrini Vincent J Minx Patrick 2012 01 01 The Oxytricha trifallax Mitochondrial Genome Genome Biology and Evolution 4 2 136 154 doi 10 1093 gbe evr136 PMC 3318907 PMID 22179582 Zoller Stephen D Hammersmith Robert L Swart Estienne C Higgins Brian P Doak Thomas G Herrick Glenn Landweber Laura F 2012 Characterization and Taxonomic Validity of the Ciliate Oxytricha trifallax Class Spirotrichea Based on Multiple Gene Sequences Limitations in Identifying Genera Solely by Morphology Protist 163 4 643 657 doi 10 1016 j protis 2011 12 006 PMC 3433844 PMID 22325790 Other resources edit OxyDB Oxytricha Genome Database Wiki In one of nature s innovations a single cell smashes and rebuilds its own genome Retrieved from https en wikipedia org w index php title Sterkiella histriomuscorum amp oldid 1218895774, wikipedia, wiki, book, books, library,
