PMID- 27707747
OWN - NLM
STAT- MEDLINE
DCOM- 20170821
LR  - 20220310
IS  - 1095-8290 (Electronic)
IS  - 0305-7364 (Print)
IS  - 0305-7364 (Linking)
VI  - 119
IP  - 1
DP  - 2017 Jan
TI  - Gene conversion events and variable degree of homogenization of rDNA loci in 
      cultivars of Brassica napus.
PG  - 13-26
LID - 10.1093/aob/mcw187 [doi]
AB  - BACKGROUND AND AIMS: Brassica napus (AACC, 2n = 38, oilseed rape) is a relatively 
      recent allotetraploid species derived from the putative progenitor diploid 
      species Brassica rapa (AA, 2n = 20) and Brassica oleracea (CC, 2n = 18). To 
      determine the influence of intensive breeding conditions on the evolution of its 
      genome, we analysed structure and copy number of rDNA in 21 cultivars of B. 
      napus, representative of genetic diversity. METHODS: We used next-generation 
      sequencing genomic approaches, Southern blot hybridization, expression analysis 
      and fluorescence in situ hybridization (FISH). Subgenome-specific sequences 
      derived from rDNA intergenic spacers (IGS) were used as probes for identification 
      of loci composition on chromosomes. KEY RESULTS: Most B. napus cultivars (18/21, 
      86 %) had more A-genome than C-genome rDNA copies. Three cultivars analysed by 
      FISH ('Darmor', 'Yudal' and 'Asparagus kale') harboured the same number (12 per 
      diploid set) of loci. In B. napus 'Darmor', the A-genome-specific rDNA probe 
      hybridized to all 12 rDNA loci (eight on the A-genome and four on the C-genome) 
      while the C-genome-specific probe showed weak signals on the C-genome loci only. 
      Deep sequencing revealed high homogeneity of arrays suggesting that the C-genome 
      genes were largely overwritten by the A-genome variants in B. napus 'Darmor'. In 
      contrast, B. napus 'Yudal' showed a lack of gene conversion evidenced by additive 
      inheritance of progenitor rDNA variants and highly localized hybridization 
      signals of subgenome-specific probes on chromosomes. Brassica napus 'Asparagus 
      kale' showed an intermediate pattern to 'Darmor' and 'Yudal'. At the expression 
      level, most cultivars (95 %) exhibited stable A-genome nucleolar dominance while 
      one cultivar ('Norin 9') showed co-dominance. CONCLUSIONS: The B. napus cultivars 
      differ in the degree and direction of rDNA homogenization. The prevalent 
      direction of gene conversion (towards the A-genome) correlates with the direction 
      of expression dominance indicating that gene activity may be needed for 
      interlocus gene conversion.
CI  - (c) The Author 2016. Published by Oxford University Press on behalf of the Annals 
      of Botany Company.
FAU - Sochorova, Jana
AU  - Sochorova J
AD  - Laboratory of Molecular Epigenetics, Institute of Biophysics, Kralovopolska 135, 
      61265 Brno, Czech Academy of Science, v.v.i., Czech Republic.
FAU - Coriton, Olivier
AU  - Coriton O
AD  - Institut National de la Recherche Agronomique (INRA), UMR 1349 IGEPP, BP 35327, 
      F-35653 Le Rheu cedex, France.
FAU - Kuderova, Alena
AU  - Kuderova A
AD  - Laboratory of Molecular Epigenetics, Institute of Biophysics, Kralovopolska 135, 
      61265 Brno, Czech Academy of Science, v.v.i., Czech Republic.
FAU - Lunerova, Jana
AU  - Lunerova J
AD  - Laboratory of Molecular Epigenetics, Institute of Biophysics, Kralovopolska 135, 
      61265 Brno, Czech Academy of Science, v.v.i., Czech Republic.
FAU - Chevre, Anne-Marie
AU  - Chevre AM
AD  - Institut National de la Recherche Agronomique (INRA), UMR 1349 IGEPP, BP 35327, 
      F-35653 Le Rheu cedex, France.
FAU - Kovarik, Ales
AU  - Kovarik A
AD  - Laboratory of Molecular Epigenetics, Institute of Biophysics, Kralovopolska 135, 
      61265 Brno, Czech Academy of Science, v.v.i., Czech Republic kovarik@ibp.cz.
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20161005
PL  - England
TA  - Ann Bot
JT  - Annals of botany
JID - 0372347
RN  - 0 (DNA, Ribosomal)
SB  - IM
MH  - Blotting, Southern
MH  - Brassica napus/*genetics
MH  - DNA, Ribosomal/*genetics
MH  - Gene Conversion/*genetics
MH  - Gene Expression Profiling
MH  - Genetic Loci/genetics
MH  - Genetic Variation/genetics
MH  - High-Throughput Nucleotide Sequencing
MH  - In Situ Hybridization, Fluorescence
PMC - PMC5218374
OTO - NOTNLM
OT  - Brassica napus
OT  - allopolyploidy
OT  - chromosome evolution
OT  - gene conversion
OT  - rDNA
EDAT- 2016/10/07 06:00
MHDA- 2017/08/22 06:00
PMCR- 2016/10/05
CRDT- 2016/10/07 06:00
PHST- 2016/05/27 00:00 [received]
PHST- 2016/07/12 00:00 [accepted]
PHST- 2016/10/07 06:00 [pubmed]
PHST- 2017/08/22 06:00 [medline]
PHST- 2016/10/07 06:00 [entrez]
PHST- 2016/10/05 00:00 [pmc-release]
AID - mcw187 [pii]
AID - 10.1093/aob/mcw187 [doi]
PST - ppublish
SO  - Ann Bot. 2017 Jan;119(1):13-26. doi: 10.1093/aob/mcw187. Epub 2016 Oct 5.