Centromere Locations in Brassica A and C Genomes Revealed Through Half-Tetrad Analysis

Autor: Philipp E. Bayer, Jérôme Morice, Matthew N. Nelson, Anne-Marie Chèvre, Jacqueline Batley, Anouska Cousin, Naghmeh Besharat, A. Pradhan, Isobel A. P. Parkin, Mathieu Rousseau-Gueutin, Annaliese S. Mason
Přispěvatelé: Justus-Liebig-Universität Gießen (JLU), University of Queensland (UQ), Institut de Génétique, Environnement et Protection des Plantes (IGEPP), AGROCAMPUS OUEST-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de la Recherche Agronomique (INRA), The University of Western Australia (UWA), Agriculture and Agri-Food [Ottawa] (AAFC), University of Southern Queensland (USQ), Institut National de la Recherche Agronomique (INRA)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Justus-Liebig-Universität Gießen = Justus Liebig University (JLU), Institut National de la Recherche Agronomique (INRA)-Université de Rennes (UR)-AGROCAMPUS OUEST, Agriculture and Agri-Food (AAFC)
Jazyk: angličtina
Rok vydání: 2016
Předmět:
Zdroj: Genetics
Genetics, Genetics Society of America, 2016, 202 (2), pp.513-23. ⟨10.1534/genetics.115.183210⟩
Genetics, 2016, 202 (2), pp.513-23. ⟨10.1534/genetics.115.183210⟩
ISSN: 0016-6731
DOI: 10.1534/genetics.115.183210⟩
Popis: Locating centromeres on genome sequences can be challenging. The high density of repetitive elements in these regions makes sequence assembly problematic, especially when using short-read sequencing technologies. It can also be difficult to distinguish between active and recently extinct centromeres through sequence analysis. An effective solution is to identify genetically active centromeres (functional in meiosis) by half-tetrad analysis. This genetic approach involves detecting heterozygosity along chromosomes in segregating populations derived from gametes (half-tetrads). Unreduced gametes produced by first division restitution mechanisms comprise complete sets of nonsister chromatids. Along these chromatids, heterozygosity is maximal at the centromeres, and homologous recombination events result in homozygosity toward the telomeres. We genotyped populations of half-tetrad-derived individuals (from Brassica interspecific hybrids) using a high-density array of physically anchored SNP markers (Illumina Brassica 60K Infinium array). Mapping the distribution of heterozygosity in these half-tetrad individuals allowed the genetic mapping of all 19 centromeres of the Brassica A and C genomes to the reference Brassica napus genome. Gene and transposable element density across the B. napus genome were also assessed and corresponded well to previously reported genetic map positions. Known centromere-specific sequences were located in the reference genome, but mostly matched unanchored sequences, suggesting that the core centromeric regions may not yet be assembled into the pseudochromosomes of the reference genome. The increasing availability of genetic markers physically anchored to reference genomes greatly simplifies the genetic and physical mapping of centromeres using half-tetrad analysis. We discuss possible applications of this approach, including in species where half-tetrads are currently difficult to isolate.
Databáze: OpenAIRE
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