title: Variability in the amount of homoeologous pairing among F1 hybrids.
abstract: Genes involved in the exclusive pairing of homologous chromosomes have been described in several polyploid species but little is known about the activity of these genes in diploids (which have only one dose of each homoeologous genome). Analysis of the meiotic behaviour of species, natural and artificial hybrids and polyploids of Glandularia suggests that, in allopolyploids where homoeologous genomes are in two doses, regulator genes prevent homoeologous pairing. The different meiotic phenotypes in diploid F1 hybrids between Glandularia pulchella and Glandularia incisa strongly suggest that these pairing regulator genes possess an incomplete penetrance when homoeologous genomes are in only one dose. Moreover, the meiotic analysis of natural and artificial F1 hybrids suggests that the genetic constitution of parental species influences the activity of pairing regulator genes and is mainly responsible for variability in the amount of homoeologous pairing observed in diploid hybrids. In Glandularia, the pairing regulator genes originated in South American diploid species. The cytogenetic characteristics of this genus make it a good model to analyse and explore in greater depth the activity of pairing regulator genes at different ploidy levels.
authors.affiliation: CONICET (Argentina) lidialidgia@yahoo.com.ar.
authors.forename: Lidia
authors.initials: L
authors.lastname: Poggio
authors.affiliation: Cátedra de Mejoramiento Genético, Facultad de Ciencias Agrarias, Universidad Nacional de Lomas de Zamora (UNLZ), Provincia Buenos Aires, Argentina.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Greizerstein
authors.affiliation: Facultad de Ciencias Veterinarias, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina.
authors.forename: María
authors.initials: M
authors.lastname: Ferrari
keywords: Glandularia; homoeologous pairing; pairing regulator genes; variability in the hybrid meiotic behaviour