A correlation of cytological and genetical crossing-over in zea mays
A correlation of cytological and genetical crossing-over in zea mays
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DOI：
10.1073/pnas.17.8.492
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发表时间：
1931-01-01
影响因子：
11.1
通讯作者：
McClintock, B
中科院分区：
文献类型：
--
作者：
Creighton, HB;McClintock, B
在玉米中，有一对染色体在两个区域具有明显的异型性：(1)染色体短臂末端有一个增大的色旋钮；当一对中的一个成员有一个旋钮而另一个没有时，不对称是明显的；(2)同一染色体的长臂由于与非同源染色体的交换而发生的修饰。在减数分裂前期可以观察到这两对对比特征。在植物的“杂合”中，它们之间的交叉将导致这些结构特征的重组。将交换染色体具有旋钮和标准染色体无旋钮的杂合植株杂交为标准无旋钮植株时，在一定比例的后代中观察到无旋钮交换和有旋钮标准的组合，表明在负责异型性的两个特征之间的区域发生了染色体交叉。通过同时使用已知位于染色体细胞学标记区域的基因，有可能表明遗传交叉的发生与染色体交叉的发生相关。因此，基因杂交是由染色体片段交换引起的假设似乎是有道理的。
In Zea mays there is a chromosome pair visibly heteromorphic in two regions: (1) an enlarged chromatic knob on the end of the short arm of the chromosome; when one member of the pair possesses a knob and the other does not, the asymmetry is evident; (2) a modification of the long arm of the same chromosome due to an interchange between it and a non-homologous chromosome. Both pairs of contrasting features can be observed in the meiotic prophases. In a plant "heterozygous" for them, cross-overs in the region between them will result in a recombination of these structural features. When a heterozygous plant in which the interchange chromosome possesses the knob and the standard chromosome is knobless is crossed to a standard knobless plant, the combinations knobless-interchange and knobbed-standard observed in a certain proportion of the progeny indicate that chromosomal cross-overs have occurred in the region between the two features responsible for the heteromor-phism. By the simultaneous use of genes known to be in the cytologically marked region of the chromosome, it has been possible to show that the occurrence of genetic crossing-over is correlated with the occurrence of chromosomal crossing-over. Thus, the assumption which has been made that genetic crossing-over is occasioned by the exchange of chromosome segments would seem to be justified.