之间的区别PCR and DNA Sequencing

Key Difference – PCR vs DNA Sequencing

PCR and DNA sequencing are two important techniques in Molecular Biology.聚合酶链反应（PCR）是产生大量DNA片段副本的过程。DNA测序是导致精确顺序的技术nucleotidesof a given DNA fragment。This is the key difference between PCR and DNA sequencing. PCR is one of the major step involved in DNA sequencing.

CONTENTS
1。概述和关键差异
2。什么是PCR
3。什么是DNA测序
4。Side by Side Comparison – PCR vs DNA Sequencing
5.Summary

什么是PCR?

Polymerase Chain Reaction (PCR) is a DNA amplification technique used in Molecular Biology. It produces thousands to millions of copies of a particularDNAfragment. This method was developed by Kary Mullis in 1983. In this technique, the fragment of DNA to be amplified serves as the template and DNA polymerase enzyme adds complementary nucleotides to the primer which is available in the PCR mixture. At the end of the PCR reaction, many copies of the sample DNA are synthesised.

There are different components of the PCR mixture, including DNA,DNA聚合酶（TAQ聚合酶），引物（正向和反向引物），nucleotides（DNA的构建块）和一个缓冲区。PCR发生在PCR机器内，并且应将正确的PCR混合物加载到机器中，并应驱动正确的程序。该技术可从非常少量的DNA中生产成千上万到数百万个特定部分DNA的副本。

PCR反应以循环方式发生，以在凝胶上产生可见量的PCR产物。如图01所示，PCR反应，即变性，底漆退火和链延伸涉及三个主要步骤。这三个步骤在三个不同的温度下发生。DNA以互补碱基之间的氢键为双链形式存在。在暗示之前，应将双链DNA彼此分开。通过给出高温来完成。在高温下，双链DNA变性为单链。然后，底漆应更接近特定片段或DNA基因的侧面。底漆是与目标序列互补的一小部分单链DNA。在退火温度下，在变性样品DNA的侧端处的互补碱基向前和反向引物退火。底漆应具有耐热性。 Once primers anneal with sample DNA, taq polymerase enzyme initiates the synthesis of the new strands by adding nucleotides which are complementary to the target DNA. Taq polymerase is a heat stable enzyme isolated from a thermophilic bacterium called热水生植物。PCR buffer maintains the optimal conditions for the taq polymerase action. These three stages of PCR reactions are repeated to produce the required amount of PCR product. After each PCR reaction, the number of the DNA copy is doubled. Hence, an exponential amplification can be observed in PCR. PCR products can be observed using gel electrophoresis and can be purified for further studies.

PCR是医学和生物学研究中的宝贵工具。PCR在法医科学方面具有特殊的价值，因为它可以从犯罪分子的微小样本中扩增DNA并制作法医DNA概况。PCR广泛用于分子生物学领域，包括genotyping，，，，gene cloning，，，，突变detection, DNA sequencing, DNA microarrays and paternity testing, etc.

什么是DNA测序？

DNA测序是确定核苷酸的精确顺序 -腺嘌呤，鸟嘌呤，，，，cytosine andthymine在给定的DNA片段中。遗传信息使用核苷酸的正确顺序存储在DNA序列中。因此，在DNA片段中找到核苷酸的精确顺序非常重要，要了解基因的结构和功能。

DNA测序方案涉及不同的过程。第一步是隔离感兴趣的DNA或基因组DNAof an organism. Using PCR (as described above), the desired region of the DNA should be amplificated. Amplified PCR product should be separated by the gelelectrophoresis并纯化。放大片段作为测序模板。可以进行测序以下内容Sanger测序or high throughput sequencing method. Sanger sequencing requires capillary electrophoresis of resulting DNA fragments. Determination of the correct nucleotide order can be done by manual reading of autoradiographs or using automated DNA sequencers.

基因测序人类基因组project and facilitated the mapping of the human genome in 2003. In forensics, DNA sequencing enabled identification of individuals which show unique DNA sequences and identify the criminals. In medicine, DNA sequencing can be used to detect the genes responsible for genetic and other diseases, find defect genes and replace them with correct genes. In agriculture, DNA sequencing information of some microorganisms is used to produce transgenic crops with economically desired characteristics.

What is the difference between PCR and DNA Sequencing?

PCR与DNA测序
PCR process creates thousands to millions of copies of the interested DNA fragment.	DNA测序是确定给定DNA片段中核苷酸的精确顺序的过程。
结果
PCR创建了数千至数百万个特定DNA片段的副本	This results in the correct order of the bases in a particular DNA fragment.
Involvement of ddNTPs
PCR不需要DDNTP。它使用DNTP。	DNA sequencing requires ddNTPs to terminate strand formation.

Summary – PCR vs DNA Sequencing

PCR and DNA sequencing are very important tools in many areas of Molecular Biology. Amplification of the DNA fragments is done by the PCR technique while the correct order of the nucleotides of a DNA fragment is determined by the DNA sequencing. This is the difference between PCR and DNA sequencing.

参考：
1。“Polymerase Chain Reaction (PCR).” National Center for Biotechnology Information. U.S. National Library of Medicine, n.d. Web. 21 Feb. 2017.
2. Shendure，Jay和Hanlee JI。“下一代DNA测序。”自然新闻。自然出版集团，2008年10月9日。2017年2月21日

图片提供：
1. Tinojasontran的“ PCR步骤” - 通过下议院维基梅迪亚
2. Enzoklop的“聚合酶链反应” - 自己的工作(CC BY-SA 3.0)通过下议院维基梅迪亚
3. SJEF的“ DNA序列” - 通过下议院维基梅迪亚