| 摘要: |
| 测定了2株球形棕囊藻Phaeocystis globosa P1、P2的 psbA基因序列 ,发现得到的2个序列完全相同。以P2序列对比分析了P. globosa和P. antarctica的psbA基因在DNA序列、氨基酸序列和RNA二级结构上的差异性 ,发现2种棕囊藻psbA基因DNA序列和氨基酸序列非常保守 ,无插入/缺失 ,其核苷酸和氨基酸变异率分别为1.88 %和1.13 %。与核基因核苷酸的碱基替换不同 ,psbA基因核苷酸的碱基替换主要发生在密码子的第1位上 ,且不引起氨基酸的变化 ,引起氨基酸变化的碱基替换都发生在密码子的第2位和第3位上。在RNA二级结构上两序列的1～4茎环结构完全相同 ,表现出明显的棕囊藻属的特异性 ,其它结构区域差异较大 ,种间差异表现明显。由于psbA基因DNA序列和氨基酸序列非常保守 ,可能不适宜棕囊藻属的系统发育分析。但其RNA二级结构可能对于棕囊藻的分子分类有一定的参考价值。 |
| 关键词: Phaeocystis globosa P. antarctica psbA DNA序列 氨基酸序列 RNA二级结构 |
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| 基金项目:国家自然科学基金资助项目(40106014);广东省自然科学基金资助项目(000760) |
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| Comparative study of chloroplast psbA gene between Phaeocystis globosa and P. antarctica |
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| Abstract: |
| In this paper, the psbA gene sequences of P1 and P2 in Phaeocystis globosa were determined. Their DNA sequences are identical. The psbA gene sequences of P. globosa P2 and P. antarctica were compared in DNA sequence, amino acid sequence and RNA secondary structure. The results show that the psbA gene in DNA sequence and amino acid sequence is conservative. No insertion / deletion was found. The corresponding nucleotide dissimilarity of the two sequences is only 1. 88% , and the amino acid is 1. 13%. The substitution of base occurs mainly in the first base of codon and these amino acids encoded by these codons are not change. These base substitutions resulting in amino acids changing occur in the second and third base of codon. In RNA secondary structure, the 1 ～ 4 structures of stem and hairpin loop are in identity and generically conservative. Other stems or hairpin loops are obviously different, showing interspecific differences. In overall, since the DNA sequence and amino acid sequence of psbA gene are extremely conservative, the psbA gene may not be adaptable to phylogenetic analysis of Phaeocystis. But the RNA secondary structure may benefit the study on taxonomy of Phaeocystis. |
| Key words: Phaeocystis globosa P. antarctica psbA DNA sequence amino acid sequence secondary structure of RNA |
