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用种子生成单倍体植物的简单方法

 

单倍体植物在生物遗传研究中有重要作用,在植物育种中也极为重要——它们被用来生成纯合子二倍体,从而避免很多代的近亲繁殖。现在,美国加利福尼亚大学戴维斯分校的Maruthachalam Ravi 和 Simon W. L. Chan开发出一种通过种子来生成单倍体拟南芥(Arabidopsis thaliana)的简单方法。以前,单倍体的生成涉及远交种的组织培养或基因组剔除,而且很多物种用这些方法是不可能培育出单倍体的。新方法仅涉及对一种着丝点蛋白,着丝点特异性组蛋白CENH3(在人类称作CENP-A),用基因工程方法进行处理,生成在与野生型杂交后其基因组被从合子中除掉的品系。这样产生的单倍体植物只有来自野生型亲代的染色体。CENH3在真核细胞着丝点上起普遍作用,所以原则上这种方法可以推广到所有植物。


参考文献:Nature 464, 615 (2010). doi:10.1038/nature08842

Haploid plants produced by centromere-mediated genome elimination

Authors: Maruthachalam Ravi & Simon W. L. Chan
Production of haploid plants that inherit chromosomes from only one parent can greatly accelerate plant breeding. Haploids generated from a heterozygous individual and converted to diploid create instant homozygous lines, bypassing generations of inbreeding. Two methods are generally used to produce haploids. First, cultured gametophyte cells may be regenerated into haploid plants, but many species and genotypes are recalcitrant to this process. Second, haploids can be induced from rare interspecific crosses, in which one parental genome is eliminated after fertilization. The molecular basis for genome elimination is not understood, but one theory posits that centromeres from the two parent species interact unequally with the mitotic spindle, causing selective chromosome loss. Here we show that haploid Arabidopsis thaliana plants can be easily generated through seeds by manipulating a single centromere protein, the centromere-specific histone CENH3 (called CENP-A in human). When cenh3 null mutants expressing altered CENH3 proteins are crossed to wild type, chromosomes from the mutant are eliminated, producing haploid progeny. Haploids are spontaneously converted into fertile diploids through meiotic non-reduction, allowing their genotype to be perpetuated. Maternal and paternal haploids can be generated through reciprocal crosses. We have also exploited centromere-mediated genome elimination to convert a natural tetraploid Arabidopsis into a diploid, reducing its ploidy to simplify breeding. As CENH3 is universal in eukaryotes, our method may be extended to produce haploids in any plant species.

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    美国加利福尼亚大学戴维斯分校的Maruthachalam Ravi 和 Simon W. L. Chan开发出一种通过种子来生成单倍体拟南芥(Arabidopsis thaliana)的简单方法
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