利用加倍单体植物检验玉米中的分配性配对。

A test of distributive pairing in Zea mays utilizing doubly monosomic plants.

机构信息

Department of Biological Sciences, Illinois State University, Normal, Illinois, USA.

出版信息

Theor Appl Genet. 1973 Jan;43(3-4):167-73. doi: 10.1007/BF00306567.

Abstract

The v x1 deficiency in Zea mays induces chromosomal nondisjunction during the megagametophyte divisions after meiosis producing large numbers of monosomes, trisomes, double monosomes, double trisomes, and even triple monosomes. In this study, microsporogenesis in six doubly monosomic combinations was analyzed. Double monosomes in a diploid organism provide the ideal material to determine if there is an interaction between two nonhomologous univalent chromosomes because two nonhomologous chromosomes lacking partners are present in each meiotic cell.At diakinesis and metaphase I, the two nonhomologous monosomic chromosomes were infrequently "paired" (3.76% and 2.18% respectively). These estimates are the upper estimates of "pairing" of nonhomologous monosomic chromosomes and probably represent an overestimate of these values because cells with any connections between the monosomic chromosomes were scored as having nine pairs and similar connections are not infrequently observed between two bivalents.The transmission of two nonhomologous unpaired chromosomes was deduced by studying the progeny of maize plants hyperploid for two chromosomes (a B(4) and Wd ring). The two nonhomologous univalents disjoined randomly.Since no evidence for an interaction between nonhomologous univalent chromosomes which leads to their non-random disjunction to opposite poles was found in this study, these data confirm my earlier conclusion (Weber, 1966, 1969) that "distributive pairing does not occur in maize (and probably most other plants) or that it occurs with a much lower efficiency than in Drosophila females". The frequent "pairing" between nonhomologous chromosomes at diakinesis and metaphase I and the non-random distribution at anaphase I in doubly trisomic maize plants reported by Michel and Burnham (1969) was found neither in my earlier studies (Weber, 1966, 1969) nor in the present study. The current study is far more sensitive than any of the previous studies because two nonhomologous chromosomes lacking pairing partners are found in every cell of a doubly monosomic plant.

摘要

玉米的 vx1 缺陷在减数分裂后导致大配子母细胞分裂中的染色体不分离，产生大量的单倍体、三倍体、双倍单倍体、双倍三倍体，甚至三倍单倍体。在这项研究中，分析了六个双倍单倍体组合的小孢子发生。在二倍体生物中，双倍单倍体提供了确定两个非同源单价染色体之间是否存在相互作用的理想材料，因为每个减数细胞中都存在没有配对伙伴的两个非同源单价染色体。在终变期和中期 I 时，两个非同源的单倍体染色体很少“配对”（分别为 3.76%和 2.18%）。这些估计值是“配对”非同源单倍体染色体的上限估计值，并且可能代表这些值的高估，因为将具有单倍体染色体之间任何连接的细胞评分具有 9 对，并且在两个二价体之间经常观察到类似的连接。通过研究超二倍体植物（B(4) 和 Wd 环）的后代，推断出两个非同源未配对染色体的传递。两个非同源单价染色体随机分开。由于在这项研究中没有发现非同源单价染色体之间相互作用导致它们随机分离到相反的极的证据，因此这些数据证实了我之前的结论（Weber，1966 年，1969 年），即“分配配对不会发生在玉米（和可能大多数其他植物）中，或者它发生的效率比在果蝇雌性中低得多”。Michel 和 Burnham（1969 年）报道的双倍三倍体玉米植物中在终变期和中期 I 之间非同源染色体的频繁“配对”和后期 I 中非随机分布在我之前的研究（Weber，1966 年，1969 年）或当前研究中均未发现。当前的研究比以往任何研究都更加敏感，因为在双倍单倍体植物的每个细胞中都发现了缺乏配对伙伴的两个非同源染色体。