Chromosomal location and reorganization of the 45S and 5S rDNA in the Brachyscome lineariloba complex (Asteraceae)
Chromosomal location and reorganization of the 45S and 5S rDNA in the Brachyscome lineariloba complex (Asteraceae)
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DOI：
10.1007/bf02524936
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发表时间：
1997-09-01
影响因子：
2.8
通讯作者：
Kosuge, K
中科院分区：
文献类型：
--
作者：
Adachi, J;Watanabe, K;Kosuge, K
已通过使用多色荧光原位杂交 (McFISH) 确定了 Brachycome Lineariloba 复合体和两个相关物种中 45S (18S-5.8S-26S) 和 5S 核糖体 DNA 的染色体位置。 Brachyscome Lineariloba 复合体包括 5 个细胞簇，2n=4、8、10、12 和 16，每个 5S 和 45S rDNA 位点出现在 2n=4 的细胞簇中染色体上的两个位点，而在 2n=8、10、12 和 16 的细胞簇中，5S rDNA 位点的数量从 4 个增加到 8 个，与基因组添加平行二倍体（4条染色体）或单倍体（2条染色体）剂量，5S rDNA位点中，除了2n=10的细胞体外，只有一对是主要的。其余的 5S rDNA 位点较小，并且在连续的基因组添加过程中似乎减少了 5S rDNA 的单位数量。无论连续的基因组添加如何，45S rDNA 位点仅在所有细胞区中的两个核仁组织区域中检测到。45S rDNA 序列的丢失或减少似乎比线叶双歧杆菌复合体中的 5S rDNA 序列进行得更快。
The chromosomal locations of the 45S (18S-5.8S-26S) and 5S ribosomal DNA in the Brachyscome lineariloba complex and two related species have been determined by the use of multicolor fluorescence in situ hybridization (McFISH). The Brachyscome lineariloba complex includes five cytodemes with 2n=4,8,10,12 and 16, Each of the 5S and 45S rDNA loci occurs at two sites on chromosomes in cytodemes with 2n=4, While in cytodemes with 2n=8, 10, 12 and 16, the number of 5S rDNA sites increases from four to eight paralleled to the genomic addition of diploid (4 chromosomes) or haploid (2 chromosomes) dosage, Of the 5S rDNA sites, only one pair is major, except for the cytodeme with 2n=10. The remaining 5S rDNA sites are minor and seem to have reduced the unit number of the 5S rDNA during the successive genomic additions, The 45S rDNA site is detected only at two nucleolar organizing regions in all cytodemes regardless of successive genomic addition, The loss or diminution of 45S rDNA sequences seem to have proceeded more rapidly than 5S rDNA sequences in the B. lineariloba complex.