| 1. | The substitution of a purine for a pyrimidine, or vice versa is a transversion .
嘌呤为嘧啶取代或嘧啶为嘌呤所取代，叫做颠换。 |
| 2. | Transversion has the bias of a t and t a , and always happen in the 3rd position
颠换的发生主要以t - a ， a - t为主，大都发生在密码子第三位。 |
| 3. | Among the nucleotides substitution of cytb , transition is obviously higher than transversion
斑翅蝗cytb基因中核苷酸的替代转换明显高于颠换。 |
| 4. | However , marked high transition / transversion was found on loop e . this could be caused by the presence of pseudogenes . in the spacer region , elements related to tra
长度差异体现在基因间隔区，而基因区极端保守， “基本为120hp 。 |
| 5. | The average transition : transversion ratio was 1 . 0 which indicated the genetic differentiation was great . the ration was 2 in nuclear dna gene . as a rule the ts : tv ratio decreased with the increasing genetic distance
1数据分析软件，构建蚜总科蚜虫分子系统树，探讨这些类群这间的分类地位和亲缘关系，这在国内外尚属首次。 |
| 6. | ( 8 ) the substitution rate in loop regions is 2 . 24 times of that in stem regions . the transition rate is almost same ( 0 . 051 and 0 . 082 ) , compared with the results that the transversion rate of loop regions is the 12 . 67 times of that of stem regions
( 8 )环区的所有核苷酸碱基代换率为茎区的2 . 24倍，转换率几乎相同( 0 . 051和0 . 082 ) ；而环区的颠换率却高达茎区的12 . 67倍。 |
| 7. | ( 3 ) the data support that roe deer ( capreolus capreolus ) moved into hydropotinae ( presently in which there is only one species : hydropotes intermix ) and stemed its own independent genus ; ( 4 ) the results are object to the usual standpoint that dusky musk deer and alpine musk deer are two different species ; ( 5 ) it is more reasonable that moschidae ( musk deer ) is placed at the level of super family ; ( 6 ) the number of transition within 12s rrna is within the range of 2 to 20 times bigger than that of transversion ; ( 7 ) as to nucleotide composition , adenine ( a ) is much more abundant than any of other bases ( averagely 36 . 88 % ) and guanine ( g ) is the least ( averagely 17 . 65 % ) in the complete sequence , which is similar with the loop region
( 4 )黑麝与马麝的12srrna基因序列完全相同， 12srrna基因数据不支持黑麝与马麝为两个种。 ( 5 )本实验结果支持麝作为上科的分类阶元存在。 ( 6 ) 12srrna基因的碱基代换中转换数远远大于颠换数( 2 - 20倍) ( 7 ) 12srrna基因二级结构中，全序列核苷酸的碱基组成腺嘌呤( a )最多(平均为36 . 88 ) ，鸟嘌呤最低(平均17 . 65 ) ，与环区的碱基组成相类似。 |
| 8. | Sequence variation analysis exhibits high transition to transversion substitution ratios , and transitions and transversions are unsaturated in the sequence of cytochorme b gene . the base composition of the cytochrome b sequences was highly biased . using a structural model of the cytochrome b protein as a template , we divided cyt b sequence data for species within anserifomes into three functional domains
3 ）序列具有较高的转换颠换比，基因序列中的转换与颠换都未饱和，序列中的碱基组成高度偏倚： 4 ）按照细胞色素为蛋白结构模型，细胞色素b基因全序列可分为三个功能区，碱基替换饱和状况与不同功能区相关联。 |
| 9. | The results showed : ( 1 ) in the d - loop of mtdna genome from 18 individuals , there were only transition and transversion , were not insertion and deletion , and the frequency of transition was higher than transversion ; ( 2 ) and nucleotide diversity was 0 . 0011 , the sequence divergence values among haplotypes was 0 . 005
研究结果显示： ( 1 ) 18只大鸨的301bp - 330bpmtdna控制区序列的突变只有转换和颠换，无插入和缺失，且转换的频率高于颠换； ( 2 )核苷酸多态性只有0 . 0011 ，不同单元型间的序列差异值为0 . 5 。 |
| 10. | In e coli , dna polymerases are key enzymes involved in two distinguished pathways contributing to untargeted mutagenesis . replication of dna by pol v ( umuc ) , in the presence of umud1 , reca and single strand binding protein ( ssb ) , is highly mutagenic and exhibits a predominant mutation pattern of base transversion . another error prone polymerase involved in untargeted mutagenesis is pol iv , encoded by dinb gene
在umud ' ， reca和单链结合蛋白ssb的协助下， polv ( umuc )能在单链模板上催化dna合成并产生高频率的以碱基颠换为主要形式的突变；另一个与非定标性突变有关的易误dna聚合酶是pol ，为dinb基因的编码产物。 |
