title: Dynamic karyotype evolution and unique sex determination systems in Leptidea wood white butterflies.
abstract: BACKGROUND
  Chromosomal rearrangements have the potential to limit the rate and pattern of gene flow within and between species and thus play a direct role in promoting and maintaining speciation. Wood white butterflies of the genus Leptidea are excellent models to study the role of chromosome rearrangements in speciation because they show karyotype variability not only among but also within species. In this work, we investigated genome architecture of three cryptic Leptidea species (L. juvernica, L. sinapis and L. reali) by standard and molecular cytogenetic techniques in order to reveal causes of the karyotype variability.
  
  
  RESULTS
  Chromosome numbers ranged from 2n = 85 to 91 in L. juvernica and 2n = 69 to 73 in L. sinapis (both from Czech populations) to 2n = 51 to 55 in L. reali (Spanish population). We observed significant differences in chromosome numbers and localization of cytogenetic markers (rDNA and H3 histone genes) within the offspring of individual females. Using FISH with the (TTAGG) n telomeric probe we also documented the presence of multiple chromosome fusions and/or fissions and other complex rearrangements. Thus, the intraspecific karyotype variability is likely due to irregular chromosome segregation of multivalent meiotic configurations. The analysis of female meiotic chromosomes by GISH and CGH revealed multiple sex chromosomes: W1W2W3Z1Z2Z3Z4 in L. juvernica, W1W2W3Z1Z2Z3 in L. sinapis and W1W2W3W4Z1Z2Z3Z4 in L. reali.
  
  
  CONCLUSIONS
  Our results suggest a dynamic karyotype evolution and point to the role of chromosomal rearrangements in the speciation of Leptidea butterflies. Moreover, our study revealed a curious sex determination system with 3-4 W and 3-4 Z chromosomes, which is unique in the Lepidoptera and which could also have played a role in the speciation process of the three Leptidea species.
authors.affiliation: Institute of Entomology, Biology Centre CAS, 370 05, České Budějovice, Czech Republic. sichjindra@seznam.cz.|Faculty of Science, University of South Bohemia, 370 05, České Budějovice, Czech Republic. sichjindra@seznam.cz.
authors.forename: Jindra
authors.initials: J
authors.lastname: Šíchová
authors.affiliation: Faculty of Science, University of South Bohemia, 370 05, České Budějovice, Czech Republic. anna.volenikova@gmail.com.
authors.forename: Anna
authors.initials: A
authors.lastname: Voleníková
authors.affiliation: Biodiversity Institute of Ontario, University of Guelph, N1G 2W1, Guelph, ON, Canada. vlad.e.dinca@gmail.com.|Institut de Biologia Evolutiva (CSIC-Universitat Pompeu-Fabra), 08003, Barcelona, Spain. vlad.e.dinca@gmail.com.
authors.forename: Vlad
authors.initials: V
authors.lastname: Dincă
authors.affiliation: Institute of Entomology, Biology Centre CAS, 370 05, České Budějovice, Czech Republic. petr.nguyen@prf.jcu.cz.|Faculty of Science, University of South Bohemia, 370 05, České Budějovice, Czech Republic. petr.nguyen@prf.jcu.cz.
authors.forename: Petr
authors.initials: P
authors.lastname: Nguyen
authors.affiliation: Institut de Biologia Evolutiva (CSIC-Universitat Pompeu-Fabra), 08003, Barcelona, Spain. roger.vila@csic.es.
authors.forename: Roger
authors.initials: R
authors.lastname: Vila
authors.affiliation: Laboratory of Applied Entomology, Faculty of Agriculture, Iwate University, Morioka, 020-8550, Japan. sahara@iwate-u.ac.jp.
authors.forename: Ken
authors.initials: K
authors.lastname: Sahara
authors.affiliation: Institute of Entomology, Biology Centre CAS, 370 05, České Budějovice, Czech Republic. marec@entu.cas.cz.|Faculty of Science, University of South Bohemia, 370 05, České Budějovice, Czech Republic. marec@entu.cas.cz.
authors.forename: František
authors.initials: F
authors.lastname: Marec
mesh_terms: D000818:Animals; D005075:Biological Evolution; D002080:Butterflies / Q000145:classification / Q000235:genetics*; D004275:DNA, Ribosomal / Q000235:genetics; D005260:Female; D051456:Gene Flow; D006657:Histones / Q000235:genetics; D019476:Insect Proteins / Q000235:genetics; D059785:Karyotype; D008297:Male; D012730:Sex Chromosomes; D019849:Sex Determination Processes
chemical_list: D004275:DNA, Ribosomal; D006657:Histones; D019476:Insect Proteins