Chiasma formation in Arabidopsis thaliana accession Wassileskija and in two meiotic mutants
Chiasma formation in Arabidopsis thaliana accession Wassileskija and in two meiotic mutants
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DOI：
10.1023/a:1009278902994
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发表时间：
2001-01-01
影响因子：
2.6
通讯作者：
Jones, GH
中科院分区：
文献类型：
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作者：
Moran, ES;Armstrong, SJ;Jones, GH
对野生型拟南芥和两个减数分裂突变体中期花粉母细胞的减数分裂交叉现象进行了分析。以45S rDNA和5S rDNA为探针，采用荧光原位杂交技术（FISH）对5对染色体进行鉴定。发现野生型交叉频率为每细胞9.24次，与估计的基因重组值一致。个体二价交叉频率随染色体大小而变化；染色体1的平均交叉频率最高（2.14），而短顶心染色体的平均交叉频率最低（1.54和1.56）。FISH分析扩展到两个具有低残留二价和交叉频率的减数分裂突变体（asy1和dsy1）。突变体dsy1没有显示出残留二价形成的染色体偏好；相反，它显示了二价和交叉频率的普遍减少。在asy1中，最长的染色体(1)具有最低的二价频率和交叉频率，而短的染色体2具有最高的交叉频率。这对染色体可能优先参与突触和交叉的形成，因为它们与核仁有关。然而，其他因素可能在起作用，因为另一条与染色体2大小和结构相似的顶心染色体(4)没有这些交叉特性。
Meiotic chiasmata were analysed in metaphase I pollen mother cells (PMCs) of wild-type Arabidopsis thaliana and in two meiotic mutants. Fluorescence in situ hybridisation (FISH) with 45S rDNA and 5S rDNA as probes was used to identify the five chromosome pairs. A wild-type chiasma frequency of 9.24 per cell was found, consistent with estimated genetic recombination values. Individual bivalent chiasma frequencies varied according to chromosome size; chromosome 1 had the highest mean chiasma frequency (2.14) while the short acrocentric chromosomes had the lowest frequencies (1.54 and 1.56). FISH analysis was extended to two meiotic mutants (asy1 and dsy1) having low residual bivalent and chiasma frequencies. Mutant dsy1 gave no indication of chromosome preference for residual bivalent formation; instead it showed a general reduction in bivalent and chiasma frequencies. In asy1, the longest chromosome (1) had the lowest bivalent frequency and chiasma frequency while the short acrocentric: chromosome 2 had the highest frequencies. This chromosome pair may be preferentially involved in synapsis and chiasma formation because of their association with the nucleolus. However, other factors may be operating since the other acrocentric chromosome (4), with similar size and structure to chromosome 2, did not share these chiasma properties.