Science 22 August 2014 Vol. 345 no. 6199 pp. 950-953 DOI: 10.1126/science.1253435
Boulos Chalhoub, France Denoeud, Shengyi Liu, Isobel A. P. Parkin, Haibao Tang, Xiyin Wang, Julien Chiquet, Harry Belcram, Chaobo Tong, Birgit Samans, Margot Corréa, Corinne Da Silva, Jérémy Just, Cyril Falentin, Chu Shin Koh, Isabelle Le Clainche, Maria Bernard, Pascal Bento, Benjamin Noel, Karine Labadie, Adriana Alberti, Mathieu Charles, Dominique Arnaud, Hui Guo, Christian Daviaud, Salman Alamery, Kamel Jabbari, Meixia Zhao, Patrick P. Edger, Houda Chelaifa, David Tack, Gilles Lassalle, Imen Mestiri, Nicolas Schnel, Marie-Christine Le Paslier, Guangyi Fan, Victor Renault, Philippe E. Bayer, Agnieszka A. Golicz, Sahana Manoli, Tae-Ho Lee, Vinh Ha Dinh Thi, Smahane Chalabi, Qiong Hu, Chuchuan Fan, Reece Tollenaere, Yunhai Lu, Christophe Battail, Jinxiong Shen, Christine H. D. Sidebottom, Xinfa Wang, Aurélie Canaguier, Aurélie Chauveau, Aurélie Bérard, Gwenaëlle Deniot, Mei Guan, Zhongsong Liu, Fengming Sun, Yong Pyo Lim, Eric Lyons, Christopher D. Town, Ian Bancroft, Xiaowu Wang, Jinling Meng, Jianxin Ma, J. Chris Pires, Graham J. King, Dominique Brunel, Régine Delourme, Michel Renard, Jean-Marc Aury, Keith L. Adams, Jacqueline Batley, Rod J. Snowdon, Jorg Tost, David Edwards, Yongming Zhou, Wei Hua, Andrew G. Sharpe, Andrew H. Paterson, Chunyun Guan, Patrick Wincker
Oilseed rape (Brassica napus L.) was formed ~7500 years ago by hybridization between B. rapa and B. oleracea, followed by chromosome doubling, a process known as allopolyploidy. Together with more ancient polyploidizations, this conferred an aggregate 72x genome multiplication since the origin of angiosperms and high gene content. We examined the B. napus genome and the consequences of its recent duplication. The constituent An and Cn subgenomes are engaged in subtle structural, functional, and epigenetic cross-talk, with abundant homeologous exchanges. Incipient gene loss and expression divergence have begun. Selection in B. napus oilseed types has accelerated the loss of glucosinolate genes, while preserving expansion of oil biosynthesis genes. These processes provide insights into allopolyploid evolution and its relationship with crop domestication and improvement.