Chromosome inheritance and meiotic stability in allopolyploid Brassica napus
Chromosome inheritance and meiotic stability in allopolyploid Brassica napus
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DOI：
10.1093/g3journal/jkaa011
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
J Chris Pires
中科院分区：
文献类型：
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作者：
Zhiyong Xiong;Patrick P Edger;Robert T Gaeta;Yao Cao;Kanglu Zhao;Siqi Zhang;J Chris Pires
Homoeologous recombination, aneuploidy, and other genetic changes are common in resynthesized allopolyploid Brassica napus. In contrast, the chromosomes of cultivars have long been considered to be meiotically stable. To gain a better understanding the underlying mechanisms leading to stabilization in the allopolyploid, the behavior of chromosomes during meiosis can be compared by unambiguous chromosomal identification between resynthesized and natural B. napus. Compared with natural B. napus, resynthesized lines show high rates of nonhomologous centromere association, homoeologous recombination leading to translocation, homoeologous chromosome replacement, and association and breakage of 45S rDNA loci. In both natural and resynthesized B. napus we observed low rate of univalents and A-C bivalents, and early sister chromatid separations. Reciprocal homoeologous chromosome exchanges and double reductions were photographed for the first time in meiotic telophase I. Meiotic errors were non-uniformly distributed across the genome in resynthesized B. napus, and in particular homoeologs sharing synteny along their entire length exhibited multivalents at diakinesis and polysomic inheritance at telophase I. Natural B. napus appeared to resolve meiotic errors mainly by suppressing homoeologous pairing, resolving nonhomologous centromere associations and 45S rDNA associations before diakinesis, and reducing homoeologous cross-overs.
