中国农科院蔬菜花卉研究所2017年“青年英才计划”人才招聘公告

Deciphering the Diploid Ancestral Genome of the Mesohexaploid?Brassica rapa

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题目:Deciphering the Diploid Ancestral Genome of the Mesohexaploid Brassica rapa

作者:Feng Cheng, Terezie Mandáková, Jian Wu, Qi Xie, Martin A. Lysak

刊物信息:The Plant Cell May 2013 vol. 25 no. 5 1541-1554, http:/?/?dx.?doi.?org/?10.?1105/?tpc.?113.?110486

摘要:Abstract: The genus Brassica includes several important agricultural and horticultural crops. Their current genome structures were shaped by whole-genome triplication followed by extensive diploidization. The availability of several crucifer genome sequences, especially that of Chinese cabbage (Brassica rapa), enables study of the evolution of the mesohexaploid Brassica genomes from their diploid progenitors. We reconstructed three ancestral subgenomes of B. rapa (n = 10) by comparing its whole-genome sequence to ancestral and extant Brassicaceae genomes. All three B. rapa paleogenomes apparently consisted of seven chromosomes, similar to the ancestral translocation Proto-Calepineae Karyotype (tPCK; n = 7), which is the evolutionarily younger variant of the Proto-Calepineae Karyotype (n = 7). Based on comparative analysis of genome sequences or linkage maps of Brassica oleracea, Brassica nigra, radish (Raphanus sativus), and other closely related species, we propose a two-step merging of three tPCK-like genomes to form the hexaploid ancestor of the tribe Brassiceae with 42 chromosomes. Subsequent diversification of the Brassiceae was marked by extensive genome reshuffling and chromosome number reduction mediated by translocation events and followed by loss and/or inactivation of centromeres. Furthermore, via interspecies genome comparison, we refined intervals for seven of the genomic blocks of the Ancestral Crucifer Karyotype (n = 8), thus revising the key reference genome for evolutionary genomics of crucifers.

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