Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/30/2005
Publication Date: 1/5/2006
Citation: Yang, B., Xu, S.S., Oliver, R., Mcarthur, R., Guo, B., Cai, X. 2006. Meiosis in the absence of chromosome pairing and recombination [abstracts]. Plant and Animal Genome XIV Conference. Abstract No. P217:155.
Technical Abstract: Meiosis includes two successive cell divisions and leads to formation of four haploid daughter cells. The fidelity of meiosis is ensured by control mechanisms called checkpoints. Chromosomes also play an important role in the control of meiotic cell division. Extensive research has been done on meiosis using meiotic mutants. The attempt of this study was to crack this complex process using haploids that lack chromosome pairing and recombination during meiosis. We produced haploids of a tetraploid wheat line Langdon (LDN) (Triticum turgidium L. var. durum, 2n=4x=28, genomes AABB) and an F1 hybrid of another tetraploid Israel-A (ISA) (T. turgidium L. var. dicoccoides, 2n=4x=28, genomes AABB) with T. tauschii (2n=2x=14, genome DD) in which all the genomes appeared as a haploid. Meiotic process of the pollen mother cells (PMCs) in the tetraploids, haploid, and F1 hybrid were characterized using indirect immunofluorescence techniques. Both tetraploids went through a normal meiosis with a monopolar kinetochore-microtubule attachment on each of the paired homologous chromosomes (bivalent) at metaphase I (MI) and a bipolar kinetochore-microtubule attachment on each of the individual chromosomes at metaphase II (MII). No chromosome pairing was observed and all the chromosomes appeared as univalents in the haploid and F1 hybrid. Either a bipolar or a monpolar kinetochore-microtubule attachment formed to a univalent at MI. Some univalents lay outside the spindle and their kinetochores were not captured by the microtubules at all. Sister chromatids of the unpaired chromosomes did not separate until anaphase II. The LDN haploid produced restituted nuclei at the end of meiosis. Our results suggested that microtubules initially formed around chromosomes and chromosome pairing had a significant impact on the spindle assembly and cytokinesis in wheat PMCs.