LUKASZEWSKI, A.J., KOPECKÝ, David. The Ph1 Locus from Wheat Controls Meiotic Chromosome Pairing in Autotetraploid Rye (Secale cereale L.). Cytogenetic and Genome Research. 2010, 129(1-3), 117-123. ISSN 1424-8581. E-ISSN 1424-859X

The Ph1 locus on chromosome 5B enforces strictly bivalent pairing in polyploid wheat, but the exact mechanism of its action remains unknown. Pairing restriction involves not only wheat homoeologues and all alien introgressions but also differentiated homologues. In this study we show that chromosome 5B with its Ph1 locus also controls chromosome pairing in autotetraploid rye by apparently restricting chiasma formation between dissimilar homologues. Unlike in wheat, the effect appears to be dosage-dependent, which may be a reflection of an interaction between Ph1 and the rye chromosome pairing control system. With 2 doses of Ph1 present, chiasmate pairing was severely restricted resulting in a significantly higher number of univalents and bivalents per cell than in the controls. The restrictions imposed by Ph1 virtually eliminated MI pairing of chromosome arms polymorphic for their C-band patterns and did not appear to affect arms with similar patterns.