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.
Highlights
Correct segregation of chromosomes during meiosis is vital for the success of polyploid species which contain more than two sets of chromosomes that need to be sorted out during meiosis to produce balanced gametes
The pairing regulator gene/s that we propose for Glandularia resembles that of the B. napus since both preclude homoeologous pairing when homologous genomes are in two doses in the polyploids and both display incomplete penetrance when homologous genomes are in one dose in the diploids
Analysis of the meiotic behaviour of species, natural and artificial hybrids and polyploids of Glandularia strongly suggests the activity of pairing regulator genes (Ph-like) prevents homoeologous pairing when homologous genomes are in two doses in polyploids
Summary
Correct segregation of chromosomes during meiosis is vital for the success of polyploid species which contain more than two sets of chromosomes that need to be sorted out during meiosis to produce balanced gametes. Genetic determination of exclusive paring between homologous chromosomes or cytological diploidization is the process by which meiosis in polyploids leads to chromosomally and genetically balanced gametes and has been described in several species of allopolyploid origin (Bhullar et al 2014; Cifuentes et al 2010; Jenczewski et al 2003; Jenczewski and Alix 2004). The best understood is the Ph1 locus of wheat, which suppresses pairing between homoeologous genomes.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
