title: Breakpoint structure reveals the unique origin of an interspecific chromosomal inversion (2La) in the Anopheles gambiae complex.
abstract: Paracentric chromosomal inversions are major architects of organismal evolution and have been associated with adaptations relevant to malaria transmission in anopheline mosquitoes. The processes responsible for their origin and maintenance, still poorly understood, can be illuminated by analysis of inversion breakpoint sequences. Here, we report the breakpoint structure of chromosomal inversion 2La from the principal malaria vector Anopheles gambiae and its relatives in the A. gambiae complex. The distal and proximal breakpoints of the standard (2L+a) arrangement contain gene duplications: full-length genes and their truncated copies at opposite ends. Intact genes without pseudogene copies in the alternative arrangement (2La) imply that 2L+a is derived and was viable despite damage to genes, because duplication preserved gene function. A unique origin for the interspecific 2La inversion was challenged previously by indirect genetic evidence, but breakpoint sequences determined from members of the A. gambiae complex strongly suggest their descent from a single event. The derived position of 2L+a, long considered ancestral in this medically important group, has significant implications for the phylogenetic history and the evolution of vectorial capacity in the A. gambiae complex.
authors.affiliation: Center for Tropical Disease Research and Training, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA.
authors.forename: Igor V
authors.initials: IV
authors.lastname: Sharakhov
authors.forename: Bradley J
authors.initials: BJ
authors.lastname: White
authors.forename: Maria V
authors.initials: MV
authors.lastname: Sharakhova
authors.forename: Jonathan
authors.initials: J
authors.lastname: Kayondo
authors.forename: Neil F
authors.initials: NF
authors.lastname: Lobo
authors.forename: Federica
authors.initials: F
authors.lastname: Santolamazza
authors.forename: Alessandra
authors.initials: A
authors.lastname: Della Torre
authors.forename: Frédéric
authors.initials: F
authors.lastname: Simard
authors.forename: Frank H
authors.initials: FH
authors.lastname: Collins
authors.forename: Nora J
authors.initials: NJ
authors.lastname: Besansky
mesh_terms: D000818:Animals; D000852:Anopheles / Q000235:genetics*; D001483:Base Sequence; D019457:Chromosome Breakage; D007446:Chromosome Inversion; D002875:Chromosomes / Q000235:genetics; D019143:Evolution, Molecular; D005796:Genes / Q000235:genetics; D007303:Insect Vectors / Q000235:genetics*; D008969:Molecular Sequence Data; D011544:Pseudogenes / Q000235:genetics