PrBn, a Major Gene Controlling Homeologous Pairing in Oilseed Rape (Brassica napus) Haploids

Corresponding author: Eric Jenczewski, INRA-GAP Rennes, Domaine de la Motte, BP 35327, F-35653 Le Rheu Cedex, France., jenczews{at}rennes.inra.fr (E-mail)

Communicating editor: P. J. PUKKILA

Precise control of chromosome pairing is vital for conferring meiotic, and hence reproductive, stability in sexually reproducing polyploids. Apart from the Ph1 locus of wheat that suppresses homeologous pairing, little is known about the activity of genes that contribute to the cytological diploidization of allopolyploids. In oilseed rape (Brassica napus) haploids, the amount of chromosome pairing at metaphase I (MI) of meiosis varies depending on the varieties the haploids originate from. In this study, we combined a segregation analysis with a maximum-likelihood approach to demonstrate that this variation is genetically based and controlled mainly by a gene with a major effect. A total of 244 haploids were produced from F₁ hybrids between a high- and a low-pairing variety (at the haploid stage) and their meiotic behavior at MI was characterized. Likelihood-ratio statistics were used to demonstrate that the distribution of the number of univalents among these haploids was consistent with the segregation of a diallelic major gene, presumably in a background of polygenic variation. Our observations suggest that this gene, named PrBn, is different from Ph1 and could thus provide complementary information on the meiotic stabilization of chromosome pairing in allopolyploid species.

This article has been cited by other articles:

				R. T. Gaeta, J. C. Pires, F. Iniguez-Luy, E. Leon, and T. C. Osborn Genomic Changes in Resynthesized Brassica napus and Their Effect on Gene Expression and Phenotype PLANT CELL, November 1, 2007; 19(11): 3403 - 3417. [Abstract] [Full Text] [PDF]

				S. D. Nicolas, G. L. Mignon, F. Eber, O. Coriton, H. Monod, V. Clouet, V. Huteau, A. Lostanlen, R. Delourme, B. Chalhoub, et al. Homeologous Recombination Plays a Major Role in Chromosome Rearrangements That Occur During Meiosis of Brassica napus Haploids Genetics, February 1, 2007; 175(2): 487 - 503. [Abstract] [Full Text] [PDF]

				Z. Liu, K. Adamczyk, M. Manzanares-Dauleux, F. Eber, M.-O. Lucas, R. Delourme, A. M. Chevre, and E. Jenczewski Mapping PrBn and Other Quantitative Trait Loci Responsible for the Control of Homeologous Chromosome Pairing in Oilseed Rape (Brassica napus L.) Haploids Genetics, November 1, 2006; 174(3): 1583 - 1596. [Abstract] [Full Text] [PDF]

				I. A. P. Parkin, S. M. Gulden, A. G. Sharpe, L. Lukens, M. Trick, T. C. Osborn, and D. J. Lydiate Segmental Structure of the Brassica napus Genome Based on Comparative Analysis With Arabidopsis thaliana Genetics, October 1, 2005; 171(2): 765 - 781. [Abstract] [Full Text] [PDF]

				J. A. Udall, P. A. Quijada, and T. C. Osborn Detection of Chromosomal Rearrangements Derived From Homeologous Recombination in Four Mapping Populations of Brassica napus L. Genetics, February 1, 2005; 169(2): 967 - 979. [Abstract] [Full Text] [PDF]