title: Polyploidization increases meiotic recombination frequency in Arabidopsis.
abstract: BACKGROUND
  Polyploidization is the multiplication of the whole chromosome complement and has occurred frequently in vascular plants. Maintenance of stable polyploid state over generations requires special mechanisms to control pairing and distribution of more than two homologous chromosomes during meiosis. Since a minimal number of crossover events is essential for correct chromosome segregation, we investigated whether polyploidy has an influence on the frequency of meiotic recombination.
  
  
  RESULTS
  Using two genetically linked transgenes providing seed-specific fluorescence, we compared a high number of progeny from diploid and tetraploid Arabidopsis plants. We show that rates of meiotic recombination in reciprocal crosses of genetically identical diploid and autotetraploid Arabidopsis plants were significantly higher in tetraploids compared to diploids. Although male and female gametogenesis differ substantially in meiotic recombination frequency, both rates were equally increased in tetraploids. To investigate whether multivalent formation in autotetraploids was responsible for the increased recombination rates, we also performed corresponding experiments with allotetraploid plants showing strict bivalent pairing. We found similarly increased rates in auto- and allotetraploids, suggesting that the ploidy effect is independent of chromosome pairing configurations.
  
  
  CONCLUSIONS
  The evolutionary success of polyploid plants in nature and under domestication has been attributed to buffering of mutations and sub- and neo-functionalization of duplicated genes. Should the data described here be representative for polyploid plants, enhanced meiotic recombination, and the resulting rapid creation of genetic diversity, could have also contributed to their prevalence.
authors.affiliation: Gregor Mendel Institute of Molecular Plant Biology, 1030 Vienna, Austria.
authors.forename: Ales
authors.initials: A
authors.lastname: Pecinka
authors.forename: Wei
authors.initials: W
authors.lastname: Fang
authors.forename: Marc
authors.initials: M
authors.lastname: Rehmsmeier
authors.forename: Avraham A
authors.initials: AA
authors.lastname: Levy
authors.forename: Ortrun
authors.initials: O
authors.lastname: Mittelsten Scheid
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics*; D005075:Biological Evolution; D023902:Chromosome Pairing; D032461:Chromosomes, Plant / Q000235:genetics*; D056130:Gametogenesis, Plant; D030821:Plants, Genetically Modified / Q000235:genetics; D011995:Recombination, Genetic; D057891:Tetraploidy