PMID- 23405178
OWN - NLM
STAT- MEDLINE
DCOM- 20130820
LR  - 20211021
IS  - 1932-6203 (Electronic)
IS  - 1932-6203 (Linking)
VI  - 8
IP  - 2
DP  - 2013
TI  - Are NORs always located on homeologous chromosomes? A FISH investigation with 
      rDNA and whole chromosome probes in Gymnotus fishes (Gymnotiformes).
PG  - e55608
LID - 10.1371/journal.pone.0055608 [doi]
LID - e55608
AB  - Gymnotus (Gymnotiformes, Gymnotidae) is the most diverse known Neotropical 
      electric knife fish genus. Cytogenetic studies in Gymnotus demonstrate a huge 
      karyotypic diversity for this genus, with diploid numbers ranging from 34 to 54. 
      The NOR are also variable in this genus, with both single and multiple NORs 
      described. A common interpretation is that the single NOR pair is a primitive 
      trait while multiple NORs are derivative. However this hypothesis has never been 
      fully tested. In this report we checked if the NOR-bearing chromosome and the 
      rDNA site are homeologous in different species of the genus Gymnotus: G. carapo 
      (2n = 40, 42, 54), G. mamiraua (2n = 54), G. arapaima (2n = 44), G. sylvius 
      (2n = 40), G. inaequilabiatus (2n = 54) and G. capanema (2n = 34), from the 
      monophyletic group G. carapo (Gymnotidae-Gymnotiformes), as well as G. jonasi 
      (2n = 52), belonging to the G1 group. They were analyzed with Fluorescence in 
      situ hybridization (FISH) using 18S rDNA and whole chromosome probes of the 
      NOR-bearing chromosome 20 (GCA20) of G. carapo (cytotype 2n = 42), obtained by 
      Fluorescence Activated Cell Sorting. All species of the monophyletic G. carapo 
      group show the NOR in the same single pair, confirmed by hybridization with CGA20 
      whole chromosome probe. In G. jonasi the NORs are multiple, and located on pairs 
      9, 10 and 11. In G. jonasi the GCA20 chromosome probe paints the distal half of 
      the long arm of pair 7, which is not a NOR-bearing chromosome. Thus these rDNA 
      sequences are not always in the homeologous chromosomes in different species thus 
      giving no support to the hypothesis that single NOR pairs are primitive traits 
      while multiple NORs are derived. The separation of groups of species in the genus 
      Gymnotus proposed by phylogenies with morphologic and molecular data is supported 
      by our cytogenetic data.
FAU - Milhomem, Susana S R
AU  - Milhomem SS
AD  - Laboratorio de Citogenetica, Instituto de Ciencias Biologicas, Universidade 
      Federal do Para, Belem, Para, Brazil.
FAU - Scacchetti, Priscilla C
AU  - Scacchetti PC
FAU - Pieczarka, Julio C
AU  - Pieczarka JC
FAU - Ferguson-Smith, Malcolm A
AU  - Ferguson-Smith MA
FAU - Pansonato-Alves, Jose C
AU  - Pansonato-Alves JC
FAU - O'Brien, Patricia C M
AU  - O'Brien PC
FAU - Foresti, Fausto
AU  - Foresti F
FAU - Nagamachi, Cleusa Y
AU  - Nagamachi CY
LA  - eng
GR  - Wellcome Trust/United Kingdom
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20130206
PL  - United States
TA  - PLoS One
JT  - PloS one
JID - 101285081
RN  - 0 (DNA Probes)
RN  - 0 (DNA, Ribosomal)
SB  - IM
MH  - Animals
MH  - Chromosomes/*genetics
MH  - DNA Probes
MH  - DNA, Ribosomal/*genetics
MH  - Gymnotiformes/classification/*genetics
MH  - In Situ Hybridization, Fluorescence
MH  - Nucleolus Organizer Region/*genetics
MH  - Phylogeny
MH  - Species Specificity
PMC - PMC3565972
COIS- Competing Interests: The authors have declared that no competing interests exist.
EDAT- 2013/02/14 06:00
MHDA- 2013/08/21 06:00
PMCR- 2013/02/06
CRDT- 2013/02/14 06:00
PHST- 2012/04/17 00:00 [received]
PHST- 2013/01/03 00:00 [accepted]
PHST- 2013/02/14 06:00 [entrez]
PHST- 2013/02/14 06:00 [pubmed]
PHST- 2013/08/21 06:00 [medline]
PHST- 2013/02/06 00:00 [pmc-release]
AID - PONE-D-12-11465 [pii]
AID - 10.1371/journal.pone.0055608 [doi]
PST - ppublish
SO  - PLoS One. 2013;8(2):e55608. doi: 10.1371/journal.pone.0055608. Epub 2013 Feb 6.