title: The pattern of zygotene and pachytene pairing in allotetraploid Aegilops species sharing the U genome.
abstract: Allotetraploid Aegilops species sharing the U genome, Ae. columnaris (UUMM), Ae. ovata (UUMM), Ae. triaristata (UUMM), Ae. triuncialis (UUCC) and Ae. variabilis (UUSS), regularly form bivalents at metaphase I of meiosis. The pattern of zygotene and pachytene pairing was analyzed by whole-mount surface-spreading of synaptonemal complexes under the electron microscope. The data indicated that at the zygotene stage the chromosomes were almost exclusively associated as bivalents; only a few multivalents (7%) were observed. These observations are discussed in relation to mechanisms of diploidization of polyploid meiosis.
authors.affiliation: Departamento de Genética, Facultad de Biología, Universidad Complutense, 28040, Madrid, Spain.
authors.forename: N
authors.initials: N
authors.lastname: Cuñado
authors.forename: S
authors.initials: S
authors.lastname: Callejas
authors.forename: M J
authors.initials: MJ
authors.lastname: García
authors.forename: A
authors.initials: A
authors.lastname: Fernández
authors.forename: J L
authors.initials: JL
authors.lastname: Santos