In many organisms, the difference in codon usage patterns among genes reflects variation in local base compositional biases and the intensity of natural selection. In this study, a comparative analysis was performed t...In many organisms, the difference in codon usage patterns among genes reflects variation in local base compositional biases and the intensity of natural selection. In this study, a comparative analysis was performed to investigate the characteristics of codon bias and factors in shaping the codon usage patterns among mitochondrion, chloroplast and nuclear genes in common wheat （Triticum aestivum L.）. GC contents in nuclear genes were higher than that in mitochondrion and chloroplast genes. The neutrality and correspondence analyses indicated that the codon usage in nuclear genes would be a result of relative strong mutational bias, while the codon usage patterns of mitochondrion and chloroplast genes were more conserved in GC content and influenced by translation level. The Parity Rule 2 （PR2） plot analysis showed that pyrimidines were used more frequently than purines at the third codon position in the three genomes. In addition, using a new alterative strategy, 11, 12, and 24 triplets were defined as preferred codons in the mitochondrion, chloroplast and nuclear genes, respectively. These findings suggested that the mitochondrion, chloroplast and nuclear genes shared particularly different features of codon usage and evolutionary constraints.展开更多
Codon usage in chloroplast genome of six seed plants （Arabidopsis thaliana, Populus alba, Zea mays, Triticum aestivum, Pinus koraiensis and Cycas taitungensis） was analyzed to find general patterns of codon usage in...Codon usage in chloroplast genome of six seed plants （Arabidopsis thaliana, Populus alba, Zea mays, Triticum aestivum, Pinus koraiensis and Cycas taitungensis） was analyzed to find general patterns of codon usage in chloroplast genomes of seed plants. The results show that chloroplast genomes of the six seed plants had similar codon usage patterns, with a strong bias towards a high representation of NNA and NNT codons. In chloroplast genomes of the six seed plants, the effective number of codons （ENC） for most genes was similar to that of the expected ENC based on the GC content at the third codon position, but several genes with low ENC values were laying below the expected curve. All of these data indicate that codon usage was dominated by a mutational bias in chloroplast genomes of seed plants and that selection appeared to be limited to a subset of genes and to only subtly affect codon usage. Meantime, four, six, eight, nine, ten and 12 codons were defined as the optimal codons in chloroplast genomes of the six seed plants.展开更多
目的:分析刺五加叶绿体基因组密码子的使用方式及其影响因素。方法:以刺五加叶绿体基因组的52条编码基因为材料,利用CodonW和SPSS软件进行多元统计分析和对应性分析。结果:刺五加叶绿体基因组密码子3个位置GC的量依次为46.46%,38.26%,29...目的:分析刺五加叶绿体基因组密码子的使用方式及其影响因素。方法:以刺五加叶绿体基因组的52条编码基因为材料,利用CodonW和SPSS软件进行多元统计分析和对应性分析。结果:刺五加叶绿体基因组密码子3个位置GC的量依次为46.46%,38.26%,29.88%,其中GC1与GC2呈极显著相关关系(P<0.01),GC12与GC3的相关系数为0.205,未达到显著水平。同义密码子的相对使用频率(relative synonymous codon usage,RSCU)>1的密码子共30个,其中29个以A或T碱基结尾。对应性分析的结果表明:第1轴显示了10.35%的差异,与有效密码子数(effective number of codons,ENC)和GC3显著相关,相关系数分别为-0.288,0.353;确定了刺五加叶绿体基因组的16个最优密码子。结论:刺五加叶绿体密码子第3位偏好以A或T碱基结尾,密码子使用模式受选择和突变及其他因素共同影响,其中选择的作用略大。展开更多
采用高频密码子分析法,对甜橙C itrus sinensis、温州蜜柑C.unshiu、葡萄柚C.paradisi和柠檬C.lim on等4种柑橘的蛋白质编码基因序列(codon DNA sequence,CDS)进行了分析,计算出了柑橘同义密码子相对使用频率(rela-tive frequency of sy...采用高频密码子分析法,对甜橙C itrus sinensis、温州蜜柑C.unshiu、葡萄柚C.paradisi和柠檬C.lim on等4种柑橘的蛋白质编码基因序列(codon DNA sequence,CDS)进行了分析,计算出了柑橘同义密码子相对使用频率(rela-tive frequency of synonymous codon,RFSC),确定出了4种柑橘的高频率密码子,发现不同种类柑橘偏爱密码子稍有差别.展开更多
基金Supported by the Sate Key Basic Research and Development Plan of China （2003CB715904） and the National Science Foundation for 0verseas Distinguished Young Scholar （30428003）
文摘In many organisms, the difference in codon usage patterns among genes reflects variation in local base compositional biases and the intensity of natural selection. In this study, a comparative analysis was performed to investigate the characteristics of codon bias and factors in shaping the codon usage patterns among mitochondrion, chloroplast and nuclear genes in common wheat （Triticum aestivum L.）. GC contents in nuclear genes were higher than that in mitochondrion and chloroplast genes. The neutrality and correspondence analyses indicated that the codon usage in nuclear genes would be a result of relative strong mutational bias, while the codon usage patterns of mitochondrion and chloroplast genes were more conserved in GC content and influenced by translation level. The Parity Rule 2 （PR2） plot analysis showed that pyrimidines were used more frequently than purines at the third codon position in the three genomes. In addition, using a new alterative strategy, 11, 12, and 24 triplets were defined as preferred codons in the mitochondrion, chloroplast and nuclear genes, respectively. These findings suggested that the mitochondrion, chloroplast and nuclear genes shared particularly different features of codon usage and evolutionary constraints.
基金supported in part by the Hi-Tech Re-search and Development Program of China ("863" Program) (No. 2007AA02Z329)the National Natural Science Foundation of China (Grant No. 20060213024)
文摘Codon usage in chloroplast genome of six seed plants （Arabidopsis thaliana, Populus alba, Zea mays, Triticum aestivum, Pinus koraiensis and Cycas taitungensis） was analyzed to find general patterns of codon usage in chloroplast genomes of seed plants. The results show that chloroplast genomes of the six seed plants had similar codon usage patterns, with a strong bias towards a high representation of NNA and NNT codons. In chloroplast genomes of the six seed plants, the effective number of codons （ENC） for most genes was similar to that of the expected ENC based on the GC content at the third codon position, but several genes with low ENC values were laying below the expected curve. All of these data indicate that codon usage was dominated by a mutational bias in chloroplast genomes of seed plants and that selection appeared to be limited to a subset of genes and to only subtly affect codon usage. Meantime, four, six, eight, nine, ten and 12 codons were defined as the optimal codons in chloroplast genomes of the six seed plants.
文摘目的:分析刺五加叶绿体基因组密码子的使用方式及其影响因素。方法:以刺五加叶绿体基因组的52条编码基因为材料,利用CodonW和SPSS软件进行多元统计分析和对应性分析。结果:刺五加叶绿体基因组密码子3个位置GC的量依次为46.46%,38.26%,29.88%,其中GC1与GC2呈极显著相关关系(P<0.01),GC12与GC3的相关系数为0.205,未达到显著水平。同义密码子的相对使用频率(relative synonymous codon usage,RSCU)>1的密码子共30个,其中29个以A或T碱基结尾。对应性分析的结果表明:第1轴显示了10.35%的差异,与有效密码子数(effective number of codons,ENC)和GC3显著相关,相关系数分别为-0.288,0.353;确定了刺五加叶绿体基因组的16个最优密码子。结论:刺五加叶绿体密码子第3位偏好以A或T碱基结尾,密码子使用模式受选择和突变及其他因素共同影响,其中选择的作用略大。
文摘采用高频密码子分析法,对甜橙C itrus sinensis、温州蜜柑C.unshiu、葡萄柚C.paradisi和柠檬C.lim on等4种柑橘的蛋白质编码基因序列(codon DNA sequence,CDS)进行了分析,计算出了柑橘同义密码子相对使用频率(rela-tive frequency of synonymous codon,RFSC),确定出了4种柑橘的高频率密码子,发现不同种类柑橘偏爱密码子稍有差别.
