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| 00:01 | | 00:01 | ||
− | |Welcome to this tutorial on '''Introduction to Biopython''' | + | |Welcome to this tutorial on '''Introduction to Biopython'''. |
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| 00:05 | | 00:05 | ||
− | |In this tutorial, we will learn about important features of '''Biopython''' | + | |In this tutorial, we will learn about: * important features of '''Biopython''' |
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| 00:10 | | 00:10 | ||
− | |Information regarding download and installation on Linux Operating System | + | |* Information regarding download and installation on Linux Operating System |
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| 00:15 | | 00:15 | ||
− | |And '''translation''' of a DNA sequence to a protein sequence using '''Biopython''' tools. | + | |* And '''translation''' of a DNA sequence to a protein sequence using '''Biopython''' tools. |
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| 00:22 | | 00:22 | ||
− | |To follow this tutorial you should be familiar with | + | |To follow this tutorial, you should be familiar with- |
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| 00:25 | | 00:25 | ||
− | | | + | | undergraduate Biochemistry or Bioinformatics |
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| 00:29 | | 00:29 | ||
− | | | + | | and basic''' Python''' programming. |
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| 00:35 | | 00:35 | ||
− | |To record this tutorial I am using '''Ubuntu''' | + | |To record this tutorial, I am using: * '''Ubuntu OS''' version 12.04 |
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| 00:41 | | 00:41 | ||
− | |'''Python''' version 2.7.3 | + | |* '''Python''' version 2.7.3 |
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| 00:44 | | 00:44 | ||
− | |'''Ipython''' version 0.12.1 and | + | |* '''Ipython''' version 0.12.1 and |
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| 00:48 | | 00:48 | ||
− | |'''Biopython''' version 1.58 | + | |* '''Biopython''' version 1.58. |
+ | |||
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| 00:51 | | 00:51 | ||
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| 01:05 | | 01:05 | ||
− | | '''Parsing''' that is extracting information from various file formats such as '''FASTA''', '''Genbank''' etc. | + | |* '''Parsing''', that is extracting information from various file formats such as '''FASTA''', '''Genbank''' etc. |
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| 01:14 | | 01:14 | ||
− | | Download data from database websites such as '''NCBI''', '''ExPASY''' etc | + | |* Download data from database websites such as '''NCBI''', '''ExPASY''' etc. |
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| 01:22 | | 01:22 | ||
− | | Run '''Bioinformatic''' | + | |* '''Run''' '''Bioinformatic algorithm'''s such as '''BLAST'''. |
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| 01:31 | | 01:31 | ||
− | | For example to obtain '''complements''', '''transcription''',''' translation''' etc. | + | | For example- to obtain '''complements''', '''transcription''',''' translation''' etc. |
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| 01:38 | | 01:38 | ||
− | | Code for dealing with alignments | + | | Code for dealing with alignments |
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| 01:40 | | 01:40 | ||
− | | | + | | and code to split up tasks into separate processes. |
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| 01:46 | | 01:46 | ||
− | |Information regarding download | + | |Information regarding download: |
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| 01:48 | | 01:48 | ||
− | | '''Biopython''' package is not part of the '''Python''' distribution | + | | '''Biopython''' package is not part of the '''Python''' distribution; it needs to be downloaded independently. |
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| 01:54 | | 01:54 | ||
− | | For details refer the following link | + | | For details, refer to the following link. |
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| 01:59 | | 01:59 | ||
− | |Installation on '''Linux''' system | + | |Installation on '''Linux''' system: |
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| 02:13 | | 02:13 | ||
− | | Additional packages must be installed for graphic | + | | Additional packages must be installed for '''graphic output'''s and '''plot'''s. |
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| 02:18 | | 02:18 | ||
− | | Open the terminal by pressing '''Ctrl, Alt''' and '''T''' keys simultaneously. | + | | Open the '''terminal''' by pressing '''Ctrl, Alt''' and '''T''' keys simultaneously. |
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| 02:30 | | 02:30 | ||
− | | Start '''Ipython''' interpreter by typing | + | | Start '''Ipython''' interpreter by typing "ipython" and press '''Enter'''. |
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| 02:38 | | 02:38 | ||
− | |To check the installation of '''Biopython''' | + | |To check the installation of '''Biopython'''- at the prompt, type: "import Bio", press '''Enter'''. |
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| 02:54 | | 02:54 | ||
− | | Here let me remind you, '''Python''' language is case sensitive. | + | | Here, let me remind you, '''Python''' language is case sensitive. |
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| 02:59 | | 02:59 | ||
− | | Take precaution while typing keywords, variables or | + | | Take precaution while typing keywords, variables or '''function'''s. |
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| 03:22 | | 03:22 | ||
− | |First create a '''sequence object''' for coding '''DNA''' | + | |First, create a '''sequence object''' for coding '''DNA strand'''. |
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| 03:27 | | 03:27 | ||
− | |Next '''transcription''' of coding '''DNA''' strand to '''mRNA'''. | + | |Next, '''transcription''' of coding '''DNA''' strand to '''mRNA'''. |
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| 03:32 | | 03:32 | ||
− | | Finally''' translation''' of '''mRNA''' to a '''protein''' sequence. | + | | Finally,''' translation''' of '''mRNA''' to a '''protein''' sequence. |
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| 03:37 | | 03:37 | ||
− | |We will be using the coding | + | |We will be using the coding DNA strand shown on this slide, as an example. |
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| 04:08 | | 04:08 | ||
− | | At the prompt, type '''from Bio dot Seq import Seq ''' press '''Enter'''. | + | | At the prompt, type: '''from Bio dot Seq import Seq ''' press '''Enter'''. |
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| 04:32 | | 04:32 | ||
− | |To do so we will use '''IUPAC '''module from '''Alphabet '''package. | + | |To do so, we will use '''IUPAC '''module from '''Alphabet '''package. |
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| 04:38 | | 04:38 | ||
− | | At the prompt, type:'''from Bio dot Alphabet import IUPAC'''. Press '''Enter'''. | + | | At the prompt, type: '''from Bio dot Alphabet import IUPAC'''. Press '''Enter'''. |
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| 04:48 | | 04:48 | ||
− | | Note that | + | | Note that we have used '''import''' and '''from''' statements to '''load''' "Seq" and "IUPAC" modules. |
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| 05:01 | | 05:01 | ||
− | | At the prompt, type: '''cdna equal to Seq''' as in normal | + | | At the prompt, type: '''cdna equal to Seq''' as in normal '''string'''s. |
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| 05:13 | | 05:13 | ||
− | | We know our sequence is a '''DNA''' fragment. So, type: '''unambiguous DNA | + | | We know our sequence is a '''DNA''' fragment. So, type: '''unambiguous DNA '''alphabet object as an '''argument'''. |
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| 05:21 | | 05:21 | ||
− | | For the output type: '''cdna''' | + | | For the output, type: '''cdna'''. Press '''Enter'''. |
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| 05:26 | | 05:26 | ||
− | | The output shows the DNA sequence as a sequence object. | + | | The output shows the '''DNA sequence''' as a sequence object. |
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| 05:35 | | 05:35 | ||
− | | We will use the Seq module's built-in '''“transcribe”''' method. | + | | We will use the '''Seq''' module's built-in '''“transcribe”''' method. |
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| 05:45 | | 05:45 | ||
− | | At the prompt | + | | At the prompt, type: '''mrna equal to cdna dot transcribe open and close parentheses''', press '''Enter'''. |
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| 05:55 | | 05:55 | ||
− | | For the output, type''' mrna.''' Press '''Enter'''. | + | | For the output, type: ''' mrna.''' Press '''Enter'''. |
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| 06:01 | | 06:01 | ||
− | |Observe the output. | + | |Observe the output.The '''transcribe''' method replaces the '''Thiamin''' in the '''DNA''' sequence by '''Uracil'''. |
− | + | ||
− | + | ||
− | + | ||
− | + | ||
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| 06:09 | | 06:09 | ||
− | |Next, to translate this '''mRNA''' to corresponding '''protein''' sequence, use the '''translate''' method. | + | |Next, to '''translate''' this '''mRNA''' to corresponding '''protein''' sequence, use the '''translate''' method. |
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| 06:27 | | 06:27 | ||
− | | The translate method translates '''RNA''' or '''DNA''' sequence using the standard genetic code, if unspecified. | + | | The '''translate''' method translates '''RNA''' or '''DNA''' sequence using the standard genetic code, if unspecified. |
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| 06:36 | | 06:36 | ||
− | |The output shows an | + | |The output shows an amino acid sequence. |
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| 06:47 | | 06:47 | ||
− | | Observe the | + | | Observe the asterisk at the end of the protein sequence. It indicates the '''stop codon'''. |
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| 06:59 | | 06:59 | ||
− | |In ''' | + | |In Biopython, '''transcribe''' method works only on coding DNA strand. |
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| 07:04 | | 07:04 | ||
− | |However in real biological systems the process of '''transcription''' starts with a '''template strand'''. | + | |However, in real biological systems, the process of '''transcription''' starts with a '''template strand'''. |
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| 07:11 | | 07:11 | ||
− | |If you are starting with a''' template strand''', convert it to coding strand by using '''reverse complement | + | |If you are starting with a''' template strand''', convert it to coding strand by using '''reverse complement''' method, as shown on the terminal. |
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| 07:31 | | 07:31 | ||
− | |'''DNA''' sequence of any size can be translated to a | + | |'''DNA''' sequence of any size can be translated to a protein sequence using this code. |
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| 07:37 | | 07:37 | ||
− | |Let's summarize. | + | |Let's summarize.In this tutorial, we have learnt: |
− | + | ||
− | + | ||
− | + | ||
− | + | ||
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| 07:41 | | 07:41 | ||
− | |Important features of '''Biopython''' | + | | Important features of '''Biopython''' |
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| 07:43 | | 07:43 | ||
− | |Information regarding download and installation on '''Linux OS''' | + | | Information regarding download and installation on '''Linux OS''' |
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| 07:48 | | 07:48 | ||
− | |Create a sequence object for the given '''DNA''' strand. | + | | Create a sequence object for the given '''DNA''' strand. |
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| 07:52 | | 07:52 | ||
− | |'''Transcription''' of the | + | | '''Transcription''' of the DNA sequence to '''mRNA'''. |
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| 07:56 | | 07:56 | ||
− | |'''Translation''' of '''mRNA''' to | + | | '''Translation''' of '''mRNA''' to protein sequence. |
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| 08:00 | | 08:00 | ||
− | |Now for the assignment | + | |Now, for the assignment- |
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| 08:08 | | 08:08 | ||
− | |The | + | |The protein sequence has an internal '''stop codon'''. |
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| 08:11 | | 08:11 | ||
− | |As it happens in nature, translate the '''DNA''' till first | + | |As it happens in nature, translate the '''DNA''' till first '''in-frame stop codon'''. |
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| 08:20 | | 08:20 | ||
− | |Notice that | + | |Notice that we have used '''to underscore stop''' argument in the '''translate()''' method. Notice the output. |
+ | |||
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| 08:27 | | 08:27 | ||
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|08:43 | |08:43 | ||
− | |The Spoken Tutorial Project | + | |The Spoken Tutorial Project team conducts workshops and gives certificates for those who pass an online test. |
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| 08:59 | | 08:59 | ||
− | |More information on this | + | |More information on this mission is available at this link. |
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| 09:03 | | 09:03 | ||
− | |This is Snehalatha from IIT Bombay signing off. Thank you for joining. | + | |This is Snehalatha from '''IIT Bombay''', signing off. Thank you for joining. |
|} | |} |
Latest revision as of 21:03, 22 December 2017
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00:01 | Welcome to this tutorial on Introduction to Biopython. |
00:05 | In this tutorial, we will learn about: * important features of Biopython |
00:10 | * Information regarding download and installation on Linux Operating System |
00:15 | * And translation of a DNA sequence to a protein sequence using Biopython tools. |
00:22 | To follow this tutorial, you should be familiar with- |
00:25 | undergraduate Biochemistry or Bioinformatics |
00:29 | and basic Python programming. |
00:31 | Refer to the Python tutorials at the given link. |
00:35 | To record this tutorial, I am using: * Ubuntu OS version 12.04 |
00:41 | * Python version 2.7.3 |
00:44 | * Ipython version 0.12.1 and |
00:48 | * Biopython version 1.58. |
00:51 | Biopython is a collection of modules for computational biology. |
00:57 | It can perform most basic to advanced tasks required for bioinformatics. |
01:03 | Biopython tools are used for: |
01:05 | * Parsing, that is extracting information from various file formats such as FASTA, Genbank etc. |
01:14 | * Download data from database websites such as NCBI, ExPASY etc. |
01:22 | * Run Bioinformatic algorithms such as BLAST. |
01:26 | It has tools for performing common operations on sequences. |
01:31 | For example- to obtain complements, transcription, translation etc. |
01:38 | Code for dealing with alignments |
01:40 | and code to split up tasks into separate processes. |
01:46 | Information regarding download: |
01:48 | Biopython package is not part of the Python distribution; it needs to be downloaded independently. |
01:54 | For details, refer to the following link. |
01:59 | Installation on Linux system: |
02:02 | Install Python, Ipython and Biopython packages using Synaptic Package Manager. |
02:08 | Prerequisite software will be installed automatically. |
02:13 | Additional packages must be installed for graphic outputs and plots. |
02:18 | Open the terminal by pressing Ctrl, Alt and T keys simultaneously. |
02:24 | I have already installed Python, Ipython and Biopython on my system. |
02:30 | Start Ipython interpreter by typing "ipython" and press Enter. |
02:35 | IPython prompt appears on screen. |
02:38 | To check the installation of Biopython- at the prompt, type: "import Bio", press Enter. |
02:48 | If you don't get any error message, it means Biopython is installed. |
02:54 | Here, let me remind you, Python language is case sensitive. |
02:59 | Take precaution while typing keywords, variables or functions. |
03:04 | For instance, in the above line “i” in import is lowercase and “B” is uppercase in Bio. |
03:12 | In this tutorial, we will make use of Biopython modules to translate a DNA sequence. |
03:19 | It involves the following steps. |
03:22 | First, create a sequence object for coding DNA strand. |
03:27 | Next, transcription of coding DNA strand to mRNA. |
03:32 | Finally, translation of mRNA to a protein sequence. |
03:37 | We will be using the coding DNA strand shown on this slide, as an example. |
03:42 | It codes for a small protein sequence. |
03:46 | The first step is to create a sequence object for the above coding DNA strand. |
03:52 | Let us go back to the terminal. |
03:55 | For creating a sequence object, import the Seq module from Bio package. |
04:02 | The Seq module provides methods to store and process sequence objects. |
04:08 | At the prompt, type: from Bio dot Seq import Seq press Enter. |
04:17 | Next, specify the alphabets in the strand explicitly, when creating your sequence object. |
04:24 | That is to specify whether the sequence of alphabets code for nucleotides or amino acids. |
04:32 | To do so, we will use IUPAC module from Alphabet package. |
04:38 | At the prompt, type: from Bio dot Alphabet import IUPAC. Press Enter. |
04:48 | Note that we have used import and from statements to load "Seq" and "IUPAC" modules. |
04:56 | Store the sequence object in a variable called cdna. |
05:01 | At the prompt, type: cdna equal to Seq as in normal strings. |
05:08 | Enclose the sequence within double quotes and parentheses. |
05:13 | We know our sequence is a DNA fragment. So, type: unambiguous DNA alphabet object as an argument. |
05:21 | For the output, type: cdna. Press Enter. |
05:26 | The output shows the DNA sequence as a sequence object. |
05:30 | Let’s transcribe the coding DNA strand into the corresponding mRNA. |
05:35 | We will use the Seq module's built-in “transcribe” method. |
05:39 | Type the following code: |
05:41 | Store the output in a variable mrna. |
05:45 | At the prompt, type: mrna equal to cdna dot transcribe open and close parentheses, press Enter. |
05:55 | For the output, type: mrna. Press Enter. |
06:01 | Observe the output.The transcribe method replaces the Thiamin in the DNA sequence by Uracil. |
06:09 | Next, to translate this mRNA to corresponding protein sequence, use the translate method. |
06:16 | Type the following code: protein equal to mrna dot translate open and close parentheses. Press Enter. |
06:27 | The translate method translates RNA or DNA sequence using the standard genetic code, if unspecified. |
06:36 | The output shows an amino acid sequence. |
06:40 | The output also shows information regarding the presence of stop codons in the translated sequence. |
06:47 | Observe the asterisk at the end of the protein sequence. It indicates the stop codon. |
06:53 | In the above code, we have used a coding DNA strand for transcription. |
06:59 | In Biopython, transcribe method works only on coding DNA strand. |
07:04 | However, in real biological systems, the process of transcription starts with a template strand. |
07:11 | If you are starting with a template strand, convert it to coding strand by using reverse complement method, as shown on the terminal. |
07:20 | Follow the rest of the code as shown above, for the coding strand. |
07:24 | Using methods in Biopython we have translated a DNA sequence to a protein sequence. |
07:31 | DNA sequence of any size can be translated to a protein sequence using this code. |
07:37 | Let's summarize.In this tutorial, we have learnt: |
07:41 | Important features of Biopython |
07:43 | Information regarding download and installation on Linux OS |
07:48 | Create a sequence object for the given DNA strand. |
07:52 | Transcription of the DNA sequence to mRNA. |
07:56 | Translation of mRNA to protein sequence. |
08:00 | Now, for the assignment- |
08:02 | Translate the given DNA sequence into protein sequence. |
08:06 | Observe the output. |
08:08 | The protein sequence has an internal stop codon. |
08:11 | As it happens in nature, translate the DNA till first in-frame stop codon. |
08:17 | Your completed assignment should have the following code. |
08:20 | Notice that we have used to underscore stop argument in the translate() method. Notice the output. |
08:27 | The stop codon itself is not translated. |
08:31 | The stop symbol is not included at the end of your protein sequence. |
08:36 | This video summarizes the Spoken Tutorial project. |
08:39 | If you do not have good bandwidth, you can download and watch it. |
08:43 | The Spoken Tutorial Project team conducts workshops and gives certificates for those who pass an online test. |
08:50 | For more details, please write to us. |
08:53 | Spoken Tutorial Project is funded by NMEICT, MHRD, Government of India. |
08:59 | More information on this mission is available at this link. |
09:03 | This is Snehalatha from IIT Bombay, signing off. Thank you for joining. |