title: A complex recombination pattern in the genome of allotetraploid Brassica napus as revealed by a high-density genetic map.
abstract: Polyploidy plays a crucial role in plant evolution. Brassica napus (2n = 38, AACC), the most important oil crop in the Brassica genus, is an allotetraploid that originated through natural doubling of chromosomes after the hybridization of its progenitor species, B. rapa (2n = 20, AA) and B. oleracea (2n = 18, CC). A better understanding of the evolutionary relationship between B. napus and B. rapa, B. oleracea, as well as Arabidopsis, which has a common ancestor with these three species, will provide valuable information about the generation and evolution of allopolyploidy. Based on a high-density genetic map with single nucleotide polymorphism (SNP) and simple sequence repeat (SSR) markers, we performed a comparative genomic analysis of B. napus with Arabidopsis and its progenitor species B. rapa and B. oleracea. Based on the collinear relationship of B. rapa and B. oleracea in the B. napus genetic map, the B. napus genome was found to consist of 70.1% of the skeleton components of the chromosomes of B. rapa and B. oleracea, with 17.7% of sequences derived from reciprocal translocation between homoeologous chromosomes between the A- and C-genome and 3.6% of sequences derived from reciprocal translocation between non-homologous chromosomes at both intra- and inter-genomic levels. The current study thus provides insights into the formation and evolution of the allotetraploid B. napus genome, which will allow for more accurate transfer of genomic information from B. rapa, B. oleracea and Arabidopsis to B. napus.
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China; Key Laboratory of Rapeseed Genetics and Breeding of Agriculture Ministry of China, Huazhong Agricultural University, Wuhan, China.
authors.forename: Guangqin
authors.initials: G
authors.lastname: Cai
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China.
authors.forename: Qingyong
authors.initials: Q
authors.lastname: Yang
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Yi
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China.
authors.forename: Chuchuan
authors.initials: C
authors.lastname: Fan
authors.affiliation: School of Agriculture and Food Sciences, University of Queensland, St Lucia, Queensland, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Edwards
authors.affiliation: School of Agriculture and Food Sciences, University of Queensland, St Lucia, Queensland, Australia.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Batley
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China; Key Laboratory of Rapeseed Genetics and Breeding of Agriculture Ministry of China, Huazhong Agricultural University, Wuhan, China.
authors.forename: Yongming
authors.initials: Y
authors.lastname: Zhou
mesh_terms: D029688:Brassica napus / Q000235:genetics*; D032461:Chromosomes, Plant / Q000235:genetics*; D018745:Genome, Plant / Q000502:physiology*; D020641:Polymorphism, Single Nucleotide; D011995:Recombination, Genetic / Q000502:physiology*; D057891:Tetraploidy