NCBI在线BLAST使用方法与结果详解.docx

1、NCBI在线BLAST使用方法与结果详解NCBI在线BLAST使用方法与结果详解BLAST（Basic Local Alignment Search Tool）是一套在蛋白质数据库或DNA数据库中进行相似性比较的分析工具。BLAST程序能迅速与公开数据库进行相似性序列比较。BLAST结果中的得分是对一种对相似性的统计说明。BLAST 采用一种局部的算法获得两个序列中具有相似性的序列。Blast中常用的程序介绍：1、BLASTP是蛋白序列到蛋白库中的一种查询。库中存在的每条已知序列将逐一地同每条所查序列作一对一的序列比对。2、BLASTX是核酸序列到蛋白库中的一种查询。先将核酸序列翻译成蛋白序列

2、（一条核酸序列会被翻译成可能的六条蛋白），再对每一条作一对一的蛋白序列比对。3、BLASTN是核酸序列到核酸库中的一种查询。库中存在的每条已知序列都将同所查序列作一对一地核酸序列比对。4、TBLASTN是蛋白序列到核酸库中的一种查询。与BLASTX相反，它是将库中的核酸序列翻译成蛋白序列，再同所查序列作蛋白与蛋白的比对。5、TBLASTX是核酸序列到核酸库中的一种查询。此种查询将库中的核酸序列和所查的核酸序列都翻译成蛋白（每条核酸序列会产生6条可能的蛋白序列），这样每次比对会产生36种比对阵列。下面是具体操作方法1，进入在线BLAST界面，可以选择blast特定的物种（如人，小鼠，水稻等），也

3、可以选择blast所有的核酸或蛋白序列。不同的blast程序上面已经有了介绍。这里以常用的核酸库作为例子。2，粘贴fasta格式的序列。选择一个要比对的数据库。关于数据库的说明请看NCBI在线blast数据库的简要说明。一般的话参数默认。3，blast参数的设置。注意显示的最大的结果数跟E值，E值是比较重要的。筛选的标准。最后会说明一下。4，注意一下你输入的序列长度。注意一下比对的数据库的说明。5，blast结果的图形显示。没啥好说的。6，blast结果的描述区域。注意分值与E值。分值越大越靠前了，E值越小也是这样。7，blast结果的详细比对结果。注意比对到的序列长度。评价一个blast结果

4、的标准主要有三项，E值（Expect)，一致性(Identities)，缺失或插入（Gaps）。加上长度的话，就有四个标准了。如图中显示，比对到的序列长度为1405，看Identities这一值，才匹配到1344bp,而输入的序列长度也是为1344bp（看上面的图），就说明比对到的序列要长一点。由Qurey（起始1）和Sbjct(起始35)的起始位置可知，5端是是多了一段的。有时也要注意3端的。附：E值（Expect)：表示随机匹配的可能性，E值越大，随机匹配的可能性也越大。E值接近零或为零时，具本上就是完全匹配了。一致性(Identities)：或相似性。匹配上的碱基数占总序列长的百分数。缺

5、失或插入（Gaps）：插入或缺失。用来表示。wen1）Please give a brief summary of your current recreational and leisure activities, including sports and hobbies.My current recreational and leisure activities are as follows: Reading: I am fond of reading detective novels, thrillers (e.g. Alfred Hitchcocks); Movies and TV pl

6、ay series: I am a moviegoer and recently I saw Schindlers List, which is directed by Steven Spielberg. My favorite TV play series are American sitcoms (e.g. Friends); Dancing: I am learning ballroom dance as an elective course; Sports: I always go jogging and rope skipping to keep fit; Drawing: I en

7、joy doodling and Im very good at facsimile. You can find my graffito on my sketch paper or the blank places of my textbooks.2）What clubs and societies are you a member of and in what capacity? I worked as a team player on the student team belonging to Market Research Section in Beijing New Oriental

8、School last year (Jan. 2008-Sep. 2008). New Oriental Education & Technology Group focuses on foreign language education and training. The group was listed on the New York Stock Exchange on September 7, 2006, the first private education company to achieve this feat in China.Main goal of our team: Col

9、lect and analyze useful data from activities of other education and training companies and then transfer the data into information, which will make considerable contribution to managers decisions.My duties and responsibilities: Collect data from activities of our competitors (e.g. New Channel Intern

10、ational Education Group Ltd.), including the number of students, the location of teaching building, the date of courses, new training projects, etc. Obtain the data and information by visiting their official website or consulting directly through phone call. Input and save the data in Excel in an or

11、ganized way. Participate in lectures and campaigns held by our competitors and record information such as date, place, lecturer and content in Word. Analyze merits and defects of these activities. Take part in meetings every other week to discuss difficulties we met and bring up constructive measure

12、s to solve these problems. Results and learning: Last summer holiday I received an individual prize for excellent performance of the last half years hard work. This experience cultivates my strong team spirits and the ability to work well under pressure.3）What factors have influenced your career cho

13、ice? Subjective factors: 1) Personality: Cautious, patient, responsible; sensitive and accurate with numbers; look at challenges as opportunities; a quick learner; 2) Ability: Good interpersonal skills, leadership potentials, strong team spirits, ability to work well under pressure, ability to work

14、efficiently and pay attention to detail; 3) Skills: Language Skill: Understand most articles in English, engage in an extended conversation with English-speaking foreigners, write a report or essay that communicates the desired messages; Computer Skill: Collect and analyze data with Excel, confident

15、 with other Microsoft Office applications, email and the web; Professional Skill: Attain the knowledge of accounting and financial management; analyze the financial reports basically; Objective factors:1) Family: My father is a computer teacher and my mother is an engineer. They are both intelligent

16、. I am the only child so that I have to take the financial burden and take care of them when they are old; 2) Educational background: My major is financial management and I have learnt a combination of courses in financial accounting, management accounting, Financial Management and Financial Stateme

17、nt Analysis. Other relevant courses include Accounting Computerization, Assets Appraisal and Internal Control. 3) Social background and economic trends: In the recent twelve years, China actively participates in globalization, especially the economic globalization, which has obviously affected the c

18、areer choices of Chinese young people.4）Outline your career ambitions and objectives. Short-term objective: Be involved in a dynamic and fast growing company, which provides me with great opportunities to improve my skills and accumulate experiences;Mid-term objective: After the efforts and study fo

19、r a couple of years, I could be a qualified professional such as an excellent accountant or auditor, who can be a considerable leader striving for the prosperity of the company;Long-term objective: Set up a company of my own. To be the chairman as well as CFO;Besides, I have to attain professional q

20、ualifications such as CPA, ACCA during the pursuit of my career ambitions.My current recreational and leisure activities are as follows: Guzheng, I have been learning the guzheng for some time, the music always cultivates the mind, and make people quiet down. Drawing:I am deeply loved with Chinese p

21、ainting,You can find my paintings hanging on every blank corner in my house , after every completion of a painting, I have a sense of accomplishment. Reading: I am fond of reading Poetry appreciation, Detective novels (e.g. The Da Vinci Code); Swimming:Swimming is one of my favorite sports, it makes

22、 my body get fully exercised, and whats more important,its a pretty good way to lose weight; Movies and TV play series: I am a moviegoer and recently I saw Sherlock Holmes ;My favorite movies is The Lord Of The Rings, I can even tell every scener after years of time; 1)I was one of the school securi

23、ties investment community, we organized a simulated stock investment ,and that was my first contact with the securities and financial markets, some students won a lot of money while others lose.Experienced by this community, I learned how to collect the relevant data, and the importance of sharing w

24、ith teammates, and I also gain the happiness of the actual operation.2)I was a member of the Student Union art departmentin my freshman year. 1) Personality: Cautious, patient, responsible; sensitive and accurate with numbers; look at challenges as opportunities; 2) Ability: I am willing to work wel

25、l under pressure, and I have the ability to work efficiently and pay attention to detail; 3) Language Skill: I can understand most of the English articles, and write a report or essay that communicates the desired messages; Computer Skill: Collect and analyze data with Excel, confident with other Mi

26、crosoft Office applications, email and the web; Professional Skill: I have mastered the basic knowledge of accounting bookkeeping, able to make basic financial statements analysis; 1) Family:My parents are both state-owned enterprises of the general staff. I am the only child so that I have to take

27、the financial burden and take care of them when they are old; 2) Educational background: I have a finance-related professional skills and knowledge, my academic background and professional qualifications are a good fit for this position. and I hope to put them into practice, such an interns experien

28、ce will allow me to be a better application of book knowledge, such as computerized system, financial management, audit and tax administration; After graduation I want to enter the accounting firm, I like the fast-paced life and the intense and methodical work, from where I can quickly learn a lot o

29、f professional skills and knowledge, and have access to know all walks of life, is a good opportunity to improve the quality of self; In the long term, my biggest dream is to work at the same time to obtain a masters degree ,afte accumulated enough experience and capital,I am willing to set up an ac

30、counting firm named by myself, Thus my passion for accounting, auditing will finally spread to attract more and more people to join this sacred work. Besides, I have to attain professional qualifications such as CPA, ACCA during the pursuit of my career ambitionsSubjects Institution Course dates The

31、 car driving Driving school 2010Guzheng Music Academy 2012Prizes Datescholarship 2011The national computer level 2 2010Jiangsu computer level 2 2010Intermediate English interpretation 2010Accounting qualification certificate 2010 Responsible for the collation of the original documents and books of a

32、rchiving, fill the accounting entries; Familiar with the corporate finance process, read the original certificate ; Responsible for collating the summary of the various departments of the company management fees in the first half of; Finance Assistant A situation where you have used two of KMPGs values to achieve a positive outcome KPMGs Core Values The KPMG Way is our definition of who we are, what we do, and how we do it.