Blastocystis Mitochondrial Genomes Appear to Show Multiple Independent Gains and Losses of Start and Stop Codons.
Complete mitochondrion-related organelle (MRO) genomes of several subtypes (STs) of the unicellular stramenopile Blastocystis are presented. Complete conservation of gene content and synteny in gene order is observed across all MRO genomes, comprising 27 protein coding genes, 2 ribosomal RNA genes, and 16 transfer RNA (tRNA) genes. Despite the synteny, differences in the degree of overlap between genes were observed between subtypes and also between isolates within the same subtype. Other notable features include unusual base-pairing mismatches in the predicted secondary structures of some tRNAs. Intriguingly, the rps4 gene in some MRO genomes is missing a start codon and, based on phylogenetic relationships among STs, this loss has happened twice independently. One unidentified open reading frame (orf160) is present in all MRO genomes. However, with the exception of ST4 where the feature has been lost secondarily, orf160 contains variously one or two in-frame stop codons. The overall evidence suggests that both the orf160 and rps4 genes are functional in all STs, but how they are expressed remains unclear.
Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.|Present address: Faculty of Natural Sciences, Imperial College, London, United Kingdom.
Alison S
AS
Jacob
Department of Microbiology and Infection Control, Statens Serum Institut, Copenhagen, Denmark.
Lee O'Brien
LO
Andersen
Department of Population Medicine and Diagnostic Sciences, Cornell College of Veterinary Medicine, Cornell University, Ithaca, NY.
Paulina Pavinski
PP
Bitar
Department of Population Medicine and Diagnostic Sciences, Cornell College of Veterinary Medicine, Cornell University, Ithaca, NY.|Present address: Department of Biological Sciences, College of Agriculture, Forestry and Life Sciences, Clemson University, Clemson, SC.
Vincent P
VP
Richards
Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada.
Sarah
S
Shah
Department of Population Medicine and Diagnostic Sciences, Cornell College of Veterinary Medicine, Cornell University, Ithaca, NY.
Michael J
MJ
Stanhope
Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.|Department of Microbiology and Infection Control, Statens Serum Institut, Copenhagen, Denmark.
C Rune
CR
Stensvold
Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom graham.clark@lshtm.ac.uk.
C Graham
CG
Clark
D020029:Base Pairing; D018387:Codon, Initiator / Q000235:genetics*; D018388:Codon, Terminator / Q000235:genetics*; D019143:Evolution, Molecular; D054629:Genome, Mitochondrial / Q000235:genetics*; D058977:Molecular Sequence Annotation; D016366:Open Reading Frames; D010802:Phylogeny; D012335:RNA, Ribosomal / Q000235:genetics; D012343:RNA, Transfer / Q000235:genetics; D058009:Stramenopiles / Q000145:classification / Q000235:genetics*
D018387:Codon, Initiator; D018388:Codon, Terminator; D012335:RNA, Ribosomal; D012343:RNA, Transfer
mitochondrion; phylogeny; stramenopile; tRNA