title: The DNA sequence of chromosome I of an African trypanosome: gene content, chromosome organisation, recombination and polymorphism.
abstract: The African trypanosome, Trypanosoma brucei, causes sleeping sickness in humans in sub-Saharan Africa. Here we report the sequence and analysis of the 1.1 Mb chromosome I, which encodes approximately 400 predicted genes organised into directional clusters, of which more than 100 are located in the largest cluster of 250 kb. A 160-kb region consists primarily of three gene families of unknown function, one of which contains a hotspot for retroelement insertion. We also identify five novel gene families. Indeed, almost 20% of predicted genes are members of families. In some cases, tandemly arrayed genes are 99-100% identical, suggesting an active process of amplification and gene conversion. One end of the chromosome consists of a putative bloodstream-form variant surface glycoprotein (VSG) gene expression site that appears truncated and degenerate. The other chromosome end carries VSG and expression site-associated genes and pseudogenes over 50 kb of subtelomeric sequence where, unusually, the telomere-proximal VSG gene is oriented away from the telomere. Our analysis includes the cataloguing of minor genetic variations between the chromosome I homologues and an estimate of crossing-over frequency during genetic exchange. Genetic polymorphisms are exceptionally rare in sequences located within and around the strand-switches between several gene clusters.
authors.affiliation: The Wellcome Trust Sanger Institute, The Wellcome Trust Genome Campus, Hinxton CB10 1SA, UK.
authors.forename: Neil
authors.initials: N
authors.lastname: Hall
authors.forename: Matthew
authors.initials: M
authors.lastname: Berriman
authors.forename: Nicola J
authors.initials: NJ
authors.lastname: Lennard
authors.forename: Barbara R
authors.initials: BR
authors.lastname: Harris
authors.forename: Christiane
authors.initials: C
authors.lastname: Hertz-Fowler
authors.forename: Emmanuelle N
authors.initials: EN
authors.lastname: Bart-Delabesse
authors.forename: Caroline S
authors.initials: CS
authors.lastname: Gerrard
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Atkin
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Barron
authors.forename: Sharen
authors.initials: S
authors.lastname: Bowman
authors.forename: Sarah P
authors.initials: SP
authors.lastname: Bray-Allen
authors.forename: Frédéric
authors.initials: F
authors.lastname: Bringaud
authors.forename: Louise N
authors.initials: LN
authors.lastname: Clark
authors.forename: Craig H
authors.initials: CH
authors.lastname: Corton
authors.forename: Ann
authors.initials: A
authors.lastname: Cronin
authors.forename: Robert
authors.initials: R
authors.lastname: Davies
authors.forename: Jonathon
authors.initials: J
authors.lastname: Doggett
authors.forename: Audrey
authors.initials: A
authors.lastname: Fraser
authors.forename: Eric
authors.initials: E
authors.lastname: Grüter
authors.forename: Sarah
authors.initials: S
authors.lastname: Hall
authors.forename: A David
authors.initials: AD
authors.lastname: Harper
authors.forename: Mike P
authors.initials: MP
authors.lastname: Kay
authors.forename: Vanessa
authors.initials: V
authors.lastname: Leech
authors.forename: Rebecca
authors.initials: R
authors.lastname: Mayes
authors.forename: Claire
authors.initials: C
authors.lastname: Price
authors.forename: Michael A
authors.initials: MA
authors.lastname: Quail
authors.forename: Ester
authors.initials: E
authors.lastname: Rabbinowitsch
authors.forename: Christopher
authors.initials: C
authors.lastname: Reitter
authors.forename: Kim
authors.initials: K
authors.lastname: Rutherford
authors.forename: Jürgen
authors.initials: J
authors.lastname: Sasse
authors.forename: Sarah
authors.initials: S
authors.lastname: Sharp
authors.forename: Ratna
authors.initials: R
authors.lastname: Shownkeen
authors.forename: Annette
authors.initials: A
authors.lastname: MacLeod
authors.forename: Sonya
authors.initials: S
authors.lastname: Taylor
authors.forename: Alison
authors.initials: A
authors.lastname: Tweedie
authors.forename: C Michael R
authors.initials: CM
authors.lastname: Turner
authors.forename: Andrew
authors.initials: A
authors.lastname: Tait
authors.forename: Keith
authors.initials: K
authors.lastname: Gull
authors.forename: Bart
authors.initials: B
authors.lastname: Barrell
authors.forename: Sara E
authors.initials: SE
authors.lastname: Melville
mesh_terms: D000818:Animals; D002874:Chromosome Mapping; D002875:Chromosomes / Q000235:genetics*; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics*; D017125:Genes, Protozoan / Q000235:genetics*; D018895:Microsatellite Repeats / Q000235:genetics; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D011995:Recombination, Genetic; D017422:Sequence Analysis, DNA; D014346:Trypanosoma brucei brucei / Q000235:genetics*; D014643:Variant Surface Glycoproteins, Trypanosoma / Q000235:genetics
chemical_list: D016054:DNA, Protozoan; D014643:Variant Surface Glycoproteins, Trypanosoma