title: Integration of molecular cytogenetics, dated molecular phylogeny, and model-based predictions to understand the extreme chromosome reorganization in the Neotropical genus Tonatia (Chiroptera: Phyllostomidae).
abstract: BACKGROUND
  Defining factors that contributed to the fixation of a high number of underdominant chromosomal rearrangements is a complex task because not only molecular mechanisms must be considered, but also the uniqueness of natural history attributes of each taxon. Ideally, detailed investigation of the chromosome architecture of an organism and related groups, placed within a phylogenetic context, is required. We used multiple approaches to investigate the dynamics of chromosomal evolution in lineages of bats with considerable karyotypic variation, focusing on the different facets contributing to fixation of the exceptional chromosomal changes in Tonatia saurophila. Integration of empirical data with proposed models of chromosome evolution was performed to understand the probable conditions for Tonatia's karyotypic evolution.
  
  
  RESULTS
  The trajectory of reorganization of chromosome blocks since the common ancestor of Glossophaginae and Phyllostominae subfamilies suggests that multiple tandem fusions, as well as disruption and fusions of conserved phyllostomid chromosomes were major drivers of karyotypic reshuffling in Tonatia. Considerable variation in the rates of chromosomal evolution between phyllostomid lineages was observed. Thirty-nine unique fusions and fission events reached fixation in Tonatia over a short period of time, followed by ~12 million years of chromosomal stasis. Physical mapping of repetitive DNA revealed an unusual accumulation of LINE-1 sequences on centromeric regions, probably associated with the chromosomal dynamics of this genus.
  
  
  CONCLUSIONS
  Multiple rearrangements have reached fixation in a wave-like fashion in phyllostomid bats. Different biological features of Tonatia support distinct models of rearrangement fixation, and it is unlikely that the fixations were a result of solely stochastic processes in small ancient populations. Increased recombination rates were probably facilitated by expansion of repetitive DNA, reinforced by aspects of taxon reproduction and ecology.
authors.affiliation: Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA. cibele.caio@gmail.com.
authors.forename: Cibele G
authors.initials: CG
authors.lastname: Sotero-Caio
authors.affiliation: Department of Human Genetics, Otto-von-Guericke University, Magdeburg, Germany. marianne.volleth@med.ovgu.de.
authors.forename: Marianne
authors.initials: M
authors.lastname: Volleth
authors.affiliation: Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Mississippi, MS, USA. federico.g.hoffmann@gmail.com.|Institute for Genomics, Biocomputing and Biotechnology, Mississippi State University, Mississippi State, MS, USA. federico.g.hoffmann@gmail.com.
authors.forename: Federico G
authors.initials: FG
authors.lastname: Hoffmann
authors.affiliation: Department of Biological Sciences, University of Idaho, Moscow, ID, USA. lscott@uidaho.edu.
authors.forename: LuAnn
authors.initials: L
authors.lastname: Scott
authors.affiliation: Department of Biological Sciences, University of Idaho, Moscow, ID, USA. hwichman@uidaho.edu.
authors.forename: Holly A
authors.initials: HA
authors.lastname: Wichman
authors.affiliation: The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Cambridge, UK. fy1@sanger.ac.uk.
authors.forename: Fengtang
authors.initials: F
authors.lastname: Yang
authors.affiliation: Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA. robert.baker@ttu.edu.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Baker
mesh_terms: D000818:Animals; D005075:Biological Evolution; D002685:Chiroptera / Q000145:classification* / Q000235:genetics*; D033481:Chromosomes, Mammalian; D017403:In Situ Hybridization; D059785:Karyotype; D008957:Models, Genetic; D010802:Phylogeny