Comparative analysis of crossover exchanges and chiasmata in Allium cepa x fistulosum after genomic in situ hybridization (GISH)

Chromosome Res. 1998 Nov;6(7):567-74. doi: 10.1023/a:1009296826942.


Genomic in situ hybridization (GISH) successfully differentiated homoeologous genomes in the inter-specific hybrid Allium cepa x fistulosum, thus allowing the detection of reciprocal crossover events as label exchanges in separating anaphase I chromosomes. Three of the eight chromosome pairs were positively identified by fluorescence in situ hybridization (FISH) to rDNA sequences. There was a general similarity of the GISH-based label exchange frequencies and metaphase I chiasma frequencies, but with a 20% deficit of chiasmata. Reasons for this apparent deficit are discussed. The locations of chiasmata and label exchanges are in broad agreement.

Publication types

  • Comparative Study

MeSH terms

  • Allium / genetics*
  • Allium / ultrastructure
  • Anaphase
  • Crossing Over, Genetic
  • Hybrid Cells
  • In Situ Hybridization*
  • In Situ Hybridization, Fluorescence
  • Meiosis
  • Metaphase