Comparative analysis of crossover exchanges and chiasmata in Allium cepa x fistulosum after genomic in situ hybridization (GISH).
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.
Stevenson
M
M
School of Biological Sciences, The University of Birmingham, Edgbaston, UK.
Armstrong
S J
SJ
Ford-Lloyd
B V
BV
Jones
G H
GH
D000490:Allium / Q000235:genetics* / Q000648:ultrastructure; D000705:Anaphase; D003434:Crossing Over, Genetic; D006822:Hybrid Cells; D017403:In Situ Hybridization; D017404:In Situ Hybridization, Fluorescence; D008540:Meiosis; D008677:Metaphase