Chromosome territory arrangement and homologous pairing in nuclei of Arabidopsis thaliana are predominantly random except for NOR-bearing chromosomes.
Differential painting of all five chromosome pairs of Arabidopsis thaliana revealed for the first time the interphase chromosome arrangement in a euploid plant. Side-by-side arrangement of heterologous chromosome territories and homologous association of chromosomes 1, 3 and 5 (on average in 35-50% of nuclei) are in accordance with the random frequency predicted by computer simulations. Only the nucleolus organizing region (NOR)-bearing chromosome 2 and 4 homologs associate more often than randomly, since NORs mostly attach to a single nucleolus. Somatic pairing of homologous approximately 100 kb segments occurs less frequently than homolog association, not significantly more often than expected at random and not simultaneously along the homologs. Thus, chromosome arrangement in Arabidopsis differs from that in Drosophila (characterized by somatic pairing of homologs), in spite of similar genome size, sequence organization and chromosome number. Nevertheless, in up to 31.5% of investigated Arabidopsis nuclei allelic sequences may share positions close enough for homologous recombination.
Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, 06466 Gatersleben, Germany.
Ales
A
Pecinka
Veit
V
Schubert
Armin
A
Meister
Gregor
G
Kreth
Marco
M
Klatte
Martin A
MA
Lysak
Jörg
J
Fuchs
Ingo
I
Schubert
D000818:Animals; D017360:Arabidopsis / Q000235:genetics*; D002466:Cell Nucleolus / Q000502:physiology; D002467:Cell Nucleus / Q000648:ultrastructure; D023902:Chromosome Pairing; D032461:Chromosomes, Plant / Q000235:genetics*; D003198:Computer Simulation; D018744:DNA, Plant / Q000235:genetics; D004330:Drosophila / Q000235:genetics; D015321:Gene Rearrangement; D009697:Nucleolus Organizer Region / Q000502:physiology*; D011995:Recombination, Genetic
D018744:DNA, Plant