ComGen Course

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Latest revision as of 05:35, 23 July 2011

2011 Spring

Textbook Introduction to Computational Genomics Textbook website - Software & Data

Presentation by students One chapter per each student No exam (Project submission)

(Temporary) Schedule

Chapter	Name	Pages	Presentation	Due date
python  HSRoh   Introduction 3/15/11
1	SJKim	21	03/22/11	03/18/11
2	JHLee	16	03/29/11	03/25/11
3	BHKim	23	04/05/11	03/28/11
4	JISong	17	04/19/11	04/08/11
Midterm - no exam (04/26/11)
5	HJKim	18	05/03/11	04/29/11			
5/10/11 (Budda's birthday)
6	JWLee	14	05/17/11	05/13/11
7	HSRoh	18	05/24/11	05/20/11
9	BHKim           05/31/11	05/27/11
8	JISong	12	06/07/11	06/03/11
10	Final	21	06/14/11	(Final Project)

Software

Python

about Python

Introduction to Programming using Python

Installing Python & related Modules (Windows & Linux only) Python(x,y)-2.6.5.6 (Mar 2011) - Free scientific and engineering development software download & install including almost every very useful scientific modules (Numpy, Scipy...)

Biopython 1.56 (Mar 2011) download & install

Biopython Tutorial & Cookbook

Tutorials

A Primer on Python for Life Science Researchers - PLoS Compbio

Eric Talevich - Check his presentation files

Slide #1

Slide #2

Chapters

Introduction to Python Programming: 노한성 발표자료 3-15-2011

Chapter 1

Chaos Game Representation

Exercise#1

Download a genome sequence & do basic statistical analysis
GC-content?: Solution = GC content of NC_01415 is '??? %'; Code

>>> from Bio import Entrez, SeqIO
>>> Entrez.mail = 'your@email.address'
>>> handle = Entrez.efetch(db="nucleotide",id="NC_001416",rettype="fasta")
>>> record = SeqIO.read(handle,"fasta")
>>> print record
ID: gi|9626243|ref|NC_001416.1|
Name: gi|9626243|ref|NC_001416.1|
Description: gi|9626243|ref|NC_001416.1| Enterobacteria phage lambda, complete genome
Number of features: 0
Seq('GGGCGGCGACCTCGCGGGTTTTCGCTATTTATGAAAATTTTCCGGTTTAAGGCG...ACG', SingleLetterAlphabet())
>>> print len(record)
48502
>>> record
SeqRecord(seq=Seq('GGGCGGCGACCTCGCGGGTTTTCGCTATTTATGAAAATTTTCCGGTTTAAGGCG...ACG', SingleLetterAlphabet()), id='gi|9626243|ref|NC_001416.1|', name='gi|9626243|ref|NC_001416.1|', description='gi|9626243|ref|NC_001416.1| Enterobacteria phage lambda, complete genome', dbxrefs=[])
>>> record.seq
Seq('GGGCGGCGACCTCGCGGGTTTTCGCTATTTATGAAAATTTTCCGGTTTAAGGCG...ACG', SingleLetterAlphabet())
>>> from Bio.SeqUtils import GC
>>> GC(record.seq)
49.857737825244321

GC-content scanning with window size 500 bps?
- ANS:

GC-values of windowsize 500

Code

>>> x = record.seq
>>> windowsize = 500
>>> gc_values = [ GC(x[i:(i+499)] for i in range(1,len(x)-windowsize+1) ]
>>> import pylab
>>> pylab.plot(gc_values)
>>> pylab.title("GC% 500 bp window size")
>>> pylab.xlabel("Nucleotide positions")
>>> pylab.ylabel("GC%")
>>> pylab.show()

Exercise#2

Basic Statistical Analysis

Comparing human and chimp complete mitochondiral DNA (NC_001807 and NC_001643)
- GC% Human: 44.5, Chimp: 43.7

>>> from Bio import Entrez, SeqIO
>>> handle = Entrez.efetch(db="nucleotide",id="NC_001807",rettype="fasta")
>>> record1 = SeqIO.read(handle,"fasta")
>>> handle = Entrez.efetch(db="nucleotide",id="NC_001643",rettype="fasta")
>>> record2 = SeqIO.read(handle,"fasta")
>>> from Bio.SeqUtils import GC
>>> GC(record1.seq)
44.487357431657713
>>> GC(record2.seq)
43.687326325963511
>>> len(record2.seq)
16554
>>> len(record1.seq)
16571

Exercise#3

Most frequent word

Count frequent dinucleotides in rat Mitochondiral DNA
- NC_001665

>>> from Bio import Entrez, SeqIO
>>> handle = Entrez.efetch(db="nucleotide",id="NC_001665",rettype="fasta")
>>> ratMT = SeqIO.read(handle,"fasta")
>>> base = [ ratMT.seq[i] for i in range(0,len(ratMT.seq))]
>>> a = base.count('A')
>>> g = base.count('G')
>>> c = base.count('C')
>>> t = base.count('T')
>>> di = [ str(ratMT.seq[i:(i+2)]) for i in range(0,len(ratMT.seq)-1) ]
>>> aa = di.count('AA')
>>> aa
1892
>>> a
5544

Chapter 2

related topics GeneSweep result Type I & Type II errors Statitical power

Exercise

Find all ORFs in Human, Chimp and Mouse mtDNA Repeat the ORF search on randomized mtDNA. The longest ORF in the randomized sequence? Find ORFs in H. influenzae

Exercise#1 Finding ORFs

>>> han1 = Entrez.efetch(db="nucleotide",id="NC_001807",rettype="fasta")
>>> hum = SeqIO.read(han1,"fasta")
>>> from Bio.Seq import Seq
>>> orf = hum.seq.translate(table="Vertebrate Mitochondrial")
>>> orf.count("*")
326

From Eric Talevich's presentation

# define function 1 - translate a given sequences in all 6 frames
def translate_six_frames(seq, table=2):
    rev = seq.reverse_complement()
    for i in range(3):
        yield seq[i:].translate(table)
        yield rev[i:].translate(table)


# define function 2 - translate given sequences in 6 reading frames
# & return ORFs, min_prot_len = 'k'
def translate_orfs(sequences, min_prot_len=60):
    for frame in translate_six_frames(seq):
        for prot in frame.split('*'):
            if len(prot) >= min_prot_len:
                yield prot


# actual procedure
from Bio import SeqIO
from Bio.SeqRecord import SeqRecord
from Bio.Seq import Seq

seq = hum.seq
proteins = translate_orfs(seq) 
seqrecords = (SeqRecord(seq,id='orf'+str(i))
           for i, seq in enumerate(proteins))

for rec in seqrecords:
	print ">%s lenght=%s\n%s"%(rec.id,len(rec.seq),rec.seq)

Exercise#2 Using randomized sequences

producing randomized genome


from Bio import Entrez, SeqIO
Entrez.email = ''
han1 = Entrez.efetch(db="nucleotide",id="NC_001807",rettype="fasta")
hum = SeqIO.read(han1,"fasta")

import random
from Bio.SeqRecord import SeqRecord
from Bio.Seq import Seq
nuc_list = list(hum.seq)

#shuffle sequence
random.shuffle(nuc_list)

seq = Seq(''.join(nuc_list))

def translate_six_frames(seq, table=2):
    rev = seq.reverse_complement()
    for i in range(3):
        yield seq[i:].translate(table)
        yield rev[i:].translate(table)

def translate_orfs(sequences, min_prot_len=60):
    for frame in translate_six_frames(sequences):
        for prot in frame.split('*'):
            if len(prot) >= min_prot_len:
                yield prot
from Bio.SeqRecord import SeqRecord

proteins = translate_orfs(seq)
seqrecords = (SeqRecord(seq,id='orf'+str(i+1)) 
        for i, seq in enumerate(proteins))

for rec in seqrecords:
	print ">%s lenght=%s\n%s"%(rec.id,len(rec.seq),rec.seq)

Exercise#3

see, Excercis #1


import sys
#min = int(sys.argv[1]) #threshold
min = 60

from Bio.SeqRecord import SeqRecord
proteins = translate_orfs(hinf.seq,min)
seqrecords = (SeqRecord(seq,id='orf'+str(i+1)) 
        for i, seq in enumerate(proteins))

Chapter 3

Scoring matrix: PAM matrices

What is dynamic programming? by Sean Eddy

Dynamic Programming Exercises from UCSC BME 205 class homework

Exersize#1

Local & Global alignment of X79493 and AY707088

>sp|O18381|PAX6_DROME Paired box protein Pax-6 OS=Drosophila melanogaster GN=ey PE=2 SV=3
MRNLPCLGTAGGSGLGGIAGKPSPTMEAVEASTASHRHSTSSYFATTYYHLTDDECHSGV
NQLGGVFVGGRPLPDSTRQKIVELAHSGARPCDISRILQVSNGCVSKILGRYYETGSIRP
RAIGGSKPRVATAEVVSKISQYKRECPSIFAWEIRDRLLQENVCTNDNIPSVSSINRVLR
NLAAQKEQQSTGSGSSSTSAGNSISAKVSVSIGGNVSNVASGSRGTLSSSTDLMQTATPL
NSSESGGASNSGEGSEQEAIYEKLRLLNTQHAAGPGPLEPARAAPLVGQSPNHLGTRSSH
PQLVHGNHQALQQHQQQSWPPRHYSGSWYPTSLSEIPISSAPNIASVTAYASGPSLAHSL
SPPNDIESLASIGHQRNCPVATEDIHLKKELDGHQSDETGSGEGENSNGGASNIGNTEDD
QARLILKRKLQRNRTSFTNDQIDSLEKEFERTHYPDVFARERLAGKIGLPEARIQVWFSN
RRAKWRREEKLRNQRRTPNSTGASATSSSTSATASLTDSPNSLSACSSLLSGSAGGPSVS
TINGLSSPSTLSTNVNAPTLGAGIDSSESPTPIPHIRPSCTSDNDNGRQSEDCRRVCSPC
PLGVGGHQNTHHIQSNGHAQGHALVPAISPRLNFNSGSFGAMYSNMHHTALSMSDSYGAV
TPIPSFNHSAVGPLAPPSPIPQQGDLTPSSLYPCHMTLRPPPMAPAHHHIVPGDGGRPAG
VGLGSGQSANLGASCSGSGYEVLSAYALPPPPMASSSAADSSFSAASSASANVTPHHTIA
QESCPSPCSSASHFGVAHSSGFSSDPISPAVSSYAHMSYNYASSANTMTPSSASGTSAHV
APGKQQFFASCFYSPWV

>gi|51872083|gb|AAU12168.1| paired box gene 6 isoform a [Homo sapiens]
MQNSHSGVNQLGGVFVNGRPLPDSTRQKIVELAHSGARPCDISRILQVSNGCVSKILGRYYETGSIRPRA
IGGSKPRVATPEVVSKIAQYKRECPSIFAWEIRDRLLSEGVCTNDNIPSVSSINRVLRNLASEKQQMGAD
GMYDKLRMLNGQTGSWGTRPGWYPGTSVPGQPTQDGCQQQEGGGENTNSISSNGEDSDEAQMRLQLKRKL
QRNRTSFTQEQIEALEKEFERTHYPDVFARERLAAKIDLPEARIQVWFSNRRAKWRREEKLRNQRRQASN
TPSHIPISSSFSTSVYQPIPQPTTPVSSFTSGSMLGRTDTALTNTYSALPPMPSFTMANNLPMQPPVPSQ
TSSYSCMLPTSPSVNGRSYDTYTPPHMQTHMNSQPMGTSGTTSTGLISPGVSVPVQVPGSEPDMSQYWPR
LQ

Tools - EMBOSS package - packing various sequence analysis programs

Emboss windows version - download site

Needlman-Wunsch (Global alignment) - download alignment File:Pax drome.needle.txt

Smith-Waterman (Local alignment) - download alignment File:Pax drome.water.txt

Excercise #2 Use Blast

The Statistics of Sequence Similarity Scores

P-values

Excercise #3 Find homologs

Excercise #4 Multiple sequence alignment

Clustalw@genome.jp

Clustalw@EBI

Chapter 4

What is Hidden Markov Model? by Sean Eddy
What is Bayesian statistics? by Sean Eddy

Exercise#1

Segmenting with 4-state model
- 2-state='AT' and 'GC', 4-state = A,G,C,T

Exercise#2

Draw the topology of a 2-state HMM emitting symbols (1~10) with even & odd states

Excercise#3

Sketch the general architecture of an ORF finding HMM

Chapter 5

Where did the BLOSUM62 alignment score matrix come from? by Sean Eddy

Exercise#1

Which of the modern elephants seems to be more closely related to mammoths? Hint: make a global alignment and calculate the genetic distance between them
12S rRNA sequence of Saber-Tooth Tiger can tell which of modern felines is most closest one.
Genetic distance between blue-whale, hippo and cow

Download sequences & write into a file

8 : from Bio import Entrez, SeqIO
9 : h1 = Entrez.efetch(db="nucleotide",id="NC_001601",rettype="fasta")
10: h2 = Entrez.efetch(db="nucleotide",id="NC_000889",rettype="fasta")
11: h3 = Entrez.efetch(db="nucleotide",id="NC_006853",rettype="fasta")
12: blue = SeqIO.read(h1,"fasta")
13: hipp = SeqIO.read(h2,"fasta")
14: cow = SeqIO.read(h3,"fasta")
19: seqs = [blue, hipp, cow]
20: h4 = open("seq.fasta","w")
21: SeqIO.write(seqs,h4,"fasta")
22: h4.close()

Do alignment with multiple sequence alignment program (e.g. Clustalw)
Calculate genetic distance based on the model (e.g. Juke-Cantor model) by Phylip Package (or any GUI program for phylogenetic analysis - MEGA)
Ans: a pairwise distance matrix

     Whale  Hippo Cow 
Whale 0     
Hippo 0.222 
Cow   0.226 0.226

Download all files

Chapter 6

Exercise 1 Measure Ka/Ks ratio for various mtDNA genes

target gene - human mitochondiral cytochrome C protein (protein sequence)

find homologs of chimp & mouse (or other animals) using BLAST (protein sequence)

find each nucleotide sequence

use [1] Online KaKs Calculator!

Exercise 2 Viral genomes

Exercise 3 Practice with free online software tools for measuring Ka/Ks: [2] Online KaKs Calculator!

Chapter 7

neighbor joining alogrithm - Wikipedia

Final report

Describe the whole procedure for building a neighbor joining tree of following sequences

Homo sapiens hemoglobin beta-chain mRNA

Homo sapiens hemoglobin, alpha 1 (HBA1), mRNA

Equus caballus hemoglobin, alpha 1 (HBA), mRNA

Equus caballus hemoglobin, beta (HBB), mRNA

Sperm whale synthetic myoglobin gene, complete cds

Test with nucleotide & protein sequence

do a multiple sequence alignment
calculate pairwise distance (genetic distance derived from sequence identity)
construct distance matrix
describe the step by step procedure for building a neighbor joining tree

Chapter 8

Chapter 9

A Thinking Chair

independent and identically distributed (i.i.d.)

Links

MIT BE.180 Biological Engineering Progamming (Some materials can be used in this course)
- Same Course in 2006 (OCW.MIT.EDU)
- Python tutorial in BE.180

Programming

Languages

Python (Official Site)
Biopython (Download)
- Tutorial(follow the instruction)
Pyplot Tutorial (matplotlib)
NumPy Tutorial

Packages

R (R packages)
- Manuals
- Contributed Documents

Previous years

2009 Schedule

Chapter Assign Pages	Presentation    Due date
1	이은혜	21	03/19/09	03/12/09
2	박애경	16	03/26/09	03/21/09
3	고혁진	23	04/02/09	03/26/09
4	장은혁	17	04/07/09	04/02/09
5	이예림	18	04/16/09	04/07/09
6	김소현	14	04/23/09	04/16/09
7	정진아	18	05/14/09	04/23/09
8	김윤식	12	05/21/09	04/30/09
9	김윤식	18	06/04/09	05/07/09
10	김윤식	21	06/11/09	05/14/09

No Class
- 4/30 (중간고사)
- 5/7 (학회참석, SF)
- 5/28 (학회참석, Cheju)
해당 단원은 발표 1주일전에 EKU에 올려 놓을것 (MS-Word 형식으로 제출)
발표는 해당 단원의 소개 및 요약
각 단원의 연습문제를 풀어서 제출할것 - EKU
발표한 내용을 MS-Word의 Review(검토)메뉴의 "Trace Changes" 기능을 이용하여 수정하여 제출

ComGen Course

From CSBLwiki

Latest revision as of 05:35, 23 July 2011

Contents

2011 Spring

Software

Chapters

Chapter 1

Exercise#1

Exercise#2

Exercise#3

Chapter 2

Exercise

Exercise#1 Finding ORFs

Exercise#2 Using randomized sequences

Exercise#3

Chapter 3

Exersize#1

Excercise #2 Use Blast

Excercise #3 Find homologs

Excercise #4 Multiple sequence alignment

Chapter 4

Exercise#1

Exercise#2

Excercise#3

Chapter 5

Exercise#1

Chapter 6

Chapter 7

Chapter 8

Chapter 9

A Thinking Chair

Links

Programming

Languages

Packages

Previous years

2009 Schedule

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