Synaptic patterns of rye B chromosomes. III. The deficient B.
Chromosomal pairing of a deficient B chromosome in rye has been studied by surface spreading of synaptonemal complexes in pollen mother cells from plants containing one deficient B (dB), one deficient B plus one standard B (dBstB) and one deficient B plus two standard Bs (dB2stB). Single dBs are often located peripherally in surface spread nuclei, and they undergo extensive non-homologous synapsis at pachytene. In the dBstB bivalents, homologous and non-homologous synapses occur simultaneously throughout pachytene without axial equalization. Competition for pairing between the dB and the two stBs results in a large predominance (80%) of stB bivalents. This finding is explained by the identical origin of the standard Bs and/or by the minor homology between the stB and the dB chromosomes.
Departamento de Genética, Facultad Biología, Universidad Complutense de Madrid, Spain.
M
M
Jiménez
M
M
Díez
J L
JL
Santos
D002875:Chromosomes / Q000502:physiology*; D008540:Meiosis; D008677:Metaphase; D011058:Pollen; D012434:Secale / Q000235:genetics*; D013573:Synaptonemal Complex