UCSC BME 205 Fall 2006
Bioinformatics: models and algorithms
(Last Update:
13:52 PST 1 December 2006
)
This is a required course for bioinformatics students---both
undergraduate and graduate students (pre-requisite to BME 220 and BME
230). This course is a renumbering of the old BME100+100L course and
fits in the same spot that it did in the curriculum. It is now five
units rather than six, but the workload remains approximately the same.
For catalog copy and pre-requisites, see the
main page for BME205.
Who, When, and Where:
Instructor: Kevin Karplus (
karplus@soe.ucsc.edu) http://www.soe.ucsc.edu/~karplus
Office hours: M3:30-4:30 (PSB 318)
TA: Grant Thiltgen
( thiltgen@soe.ucsc.edu)
Office hours: W 11:30-1:30 Baskin Engineering 105
Lectures:
MWF 2-3:10 Baskin Engineering 156 PSB 305
One lab section a week is highly recommended:
Location and time TBA.
Attendance at lab sections is optional but highly
recommended—it will be a time when the TA will be in the lab to
help out with Perl questions, with bioinformatics tools on the web,
with debugging, and with general help with the homework assignments.
Homework: see the schedule for due
dates and pointers to specific assignments.
Texts
There will be two required texts, plus additional readings that will
be distributed either on paper or via the Web:
- Programming Perl
Larry Wall, Tom Christiansen & Jon Orwant
latest edition
O'Reilly and Associates
- Considered the best single book on PERL—this is the
main reference work on the language, and every PERL programmer
should have a copy of it handy.
You may use other PERL tutorials or references, but I expect
you to have easy access to this one.
We will be covering just the basics of PERL, not open-source
packages like BioPerl, which you may wish to learn on your own.
-
Biological Sequence Analysis: Probabilistic Models of Proteins and
Nucleic Acids from Cambridge University Press by
R. Durbin, S. Eddy, A. Krogh, and G. Mitchison.
-
This book is a tutorial introduction to the use of hidden Markov
models and other probabilistic models for sequence analysis problems
in computational molecular biology, but is aimed mainly at a
gradauate-student audience. We've been using it for years in the
the graduate courses and used it successfully last year in BME 100.
This is a text and reference
book that every bioinformatics programmer should have.
I don't follow the book very closely, so you will have to figure out
for yourself when it is appropriate to read various sections.
Get the second edition, if you can, which has made corrections as
indicated on the errata
page.
The bookstore was unable to get copies of this book, but the first
edition is available from Amazon.com. You may be able to get better
prices by checking abebooks.com and
addall.com for a used copy. (The
results vary depending on who has the book and at what price.)
- Darling models
-
I added some assignments in 2003 to build physical
models of peptides (and DNA base pairs) using the Darling model
kits. These kits are
available over the web at http://www.darlingmodels.com/
I recommend getting the "Biochemistry" kit, though the cheaper
"protein alpha helix--pleated sheet" kit may suffice.
I have found these kits to give me a much better insight into protein
flexibility and rigidity than the standard ball-and-stick models used
in organic chemistry classes, and they are fun to play with.
To reduce costs, it is quite reasonable for students to share a kit.
Note: the science library now has Darling model kits that you can
check out!
Some initial instructions for building a protein backbone with this
model kit are available.
- An Introduction to Bioinformatics Algorithms
Neil Jones
and Pavel Pevzner
MIT Press - This is book came out in summer
2004. It looks like it may be a valuable supplementary text, as it
seems to be easier to read and at a slightly less advanced level than
the Durbin et al. book.
Evaluation
There will be four types of assignments for the class:
- reading assignments,
- pencil-and-paper exercises,
- programming exercises to learn PERL, and
- bioinformatics exercises using real data.
Based on the first running of the course in Fall 2001, there will be
no exams.
It turns out to be very difficult to make up small enough problems for
examination—almost all the homework exercises are much larger
problems than could reasonably be given on a timed exam.
The assignments will be distributed on the web (see the
schedule for details).
The relative weights of the different types of
assignment in the evaluation has not been determined yet—it should
be roughly proportional to how much time the different assignments
take to do well. We will try to assign points to each assignment as
it is given, but the total number of points won't be known until we've
created all the assignments.
Academic Integrity
Anyone caught cheating in the class will be reported to their college
provost (see UCSC
policy on academic integrity) and may fail the class.
Cheating includes any attempt to claim someone else's work as your
own.
Plagiarism in any form (including close paraphrasing) will be
considered cheating.
Use of any source without proper citation will be considered cheating.
Collaboration without explicit written acknowledgement will be
considered cheating.
Collaboration on lab assignments with explicit written acknowledgement
is encouraged—guidelines for the extent of reasonable collaboration
will be given in class.
Classroom Accomodations for Disabilities
If you qualify for classroom accommodations because of a disability,
please submit your Accommodation Authorization from the Disability
Resource Center (DRC) to me during my office hours in a timely manner,
preferably within the first two weeks of the quarter. Contact DRC at
459-2089 (voice), 459-4806 (TTY).
Rough list of topics we'll probably cover (not necessarily in order)
Note: The schedule will be updated throughout the quarter to reflect what
really happens.
- Quick review of the fundamental dogma of biology:
DNA->RNA->protein, bases, codons, amino acids
(3-4 hours)
- Stochastic models, Bayes Rule, 0-order Markov chain,
first-order Markov chain, length model versus stop character for
finite strings, use of log-probability for computations,
adding probabilities in log-prob representation (efficient
computation of log(exp(x)+exp(y)) ).
(1.5 hour)
- Constructing a model from data. Training, cross-training, and testing.
Maximum-likelihood estimate. Pseudocounts to get mean posterior estimate.
(1.5 hours)
- Converting abitrary scores to stochastic models: P-value and E-value.
Brief discussion of Z-scores (Gaussian dist.) and fat tails of
extreme-value (Gumbel dist.)
(1.5 hour)
- Entropy, relative entropy, Mutual information, sequence logos.
(1.5 hour)
- What fellowship reviewers look for.
Relationship between relative entropy and difference in encoding
cost in a train/test framework (clarification for homework exercise).
Interpreting classification results: true/false positives,
specificity, sensitivity, ROC curves, ROC_n numbers
What is a substitution matrix?
(1.5 hour)
- Substitution matrices and sequence alignment scores.
Aligning sequences to sequences, dynamic programming
We'll do the the simple, but inefficient algorithm (for
aribtrary gap costs) first.
(1 hour: Blosum substitution matrices and gapless scoring)
(1 hour: the alignment problem and global dynamic programming with
arbitrary gap costs)
(1 hour: global dynamic programming with linear gap costs,
traceback)
(1 hour: affine gap costs. Global and local dynamic programming)
- Introduction to Hidden Markov models
(1.5 hour on HMMs and profiles)
(1.5 hours on profile HMMs giving Viterbi algorithm and
forward-backward)
See powerpoint slides by Rachel Karchin (not used in class
this year).
- Dirichlet Mixtures (1.5 hours)
See
http://www.soe.ucsc.edu/research/compbio/dirichlets/dirichlet-papers.html
for papers and http://www.soe.ucsc.edu/research/compbio/dirichlets/
for general information about Dirichlet mixtures.
- Guest Lecture in the Science Library. Science librarians
will give a presentation on
bioinformatics resources available through the library, as well as
talking about some of the challenges that face the UCSC library in
building an adequate collection in new fields like bioinformatics.
- Protein secondary structure (DSSP and STRIDE), in order to
explain second track of 2-track HMM.
Discuss secondary structure prediction using neural nets.
(1.5 hours)
- Sequence weighting (Henikoff's technique for relative
weighting and target bit savings for total weight)
(1 hour)
Multiple alignment techniques
Overview and progressive alignment (0.5 hour)
- Multiple alignment techniques
Muscle and Probcons
documentation on MUSCLE:
http://www.drive5.com/muscle/docs.htm
Referreed paper:
Edgar, Robert C. (2004), MUSCLE: multiple sequence alignment with
high accuracy and high throughput, Nucleic Acids Research 32(5),
1792-97.
PROBCONS web site (including overview of algorithm):
http://probcons.stanford.edu
Oher multiple alignment programs:
paper on T-coffee:
T-Coffee: A novel method for fast and accurate multiple sequence alignment.
Notredame C, Higgins DG, Heringa J.
J Mol Biol 2000 Sep 8;302(1):205-17
paper on MAFFT:
Kazutaka Katoh, Kazuharu Misawa1, Kei-ichi Kuma and Takashi Miyata.
MAFFT: a novel method for rapid multiple sequence alignment based on fast Fourier transform.
Nucleic Acids Research 30(14):3059-3066, 2002.
- Phylogeny: brief mention of maximum-likelihood and parsimony.
Additivity assumption.
UPGMA algorithm presented, ultrametric assumption and molecular
clocks, intro to neighbor-joining (no proofs)
(1.5 hour)
- RNA structure and Stochastic Context-Free Grammars
(1.5 hour)
- A protocol for evaluating local structure alphabets.
This talk (
http://www.soe.ucsc.edu/~karplus/papers/local-structure-germany02.pdf)
presented some of the main results from Rachel Karchin's PhD thesis.
Rough list of topics we didn't have enough time to do more than
briefly mention last year:
- Contact order and folding rate.
In 2001, I handed out paper on contact order:
Contact order, transition state placement and the refolding rates of single domain proteins.
Plaxco KW, Simons KT, Baker D.
J Mol Biol 1998 Apr 10;277(4):985-94
- Phylogenetic analysis
- DNA microarrays and expression data
- Gene finding
- Proteomics
- RNA structure
- DNA assembly
- Fast methods for searching (BLAST and BLAT).
(In 2001, Jim Kent gave an excellent lecture on these.)
- RNA genes, DNA microarrays, computational and
functional genomics
Look at the BME
210 course, the BME
230 course, and the lab pages for Todd Lowe and
Josh Stuart.
- Combining secondary structure, fold-recognition, and
new-fold methods for protein structure prediction.
Using the
transparencies given at Schloss Dagstuhl.
I could have handed out
book chapter on SAM-T2K, but didn't.
Other resources on the web
- http://genome.ucsc.edu/
- UCSC Genome Browser - gateway to over 27 complete
genome sequences
- http://genome-test.cse.ucsc.edu/eng/
- Getting Started on the UCSC Genome Project Team
-
User's Guide to the Human Genome (in Nature Genetics).
Questions about page content should be directed to
Kevin Karplus
Biomolecular Engineering
University of California, Santa Cruz
Santa Cruz, CA 95064
USA
karplus@soe.ucsc.edu
1-831-459-4250