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:

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.
  1. Quick review of the fundamental dogma of biology: DNA->RNA->protein, bases, codons, amino acids
    (3-4 hours)
  2. 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)
  3. Constructing a model from data. Training, cross-training, and testing. Maximum-likelihood estimate. Pseudocounts to get mean posterior estimate. (1.5 hours)
  4. 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)
  5. Entropy, relative entropy, Mutual information, sequence logos. (1.5 hour)
  6. 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)
  7. 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)
  8. 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).
  9. 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.
  10. 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.
  11. 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)
  12. 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)
  13. 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.

  14. 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)
  15. RNA structure and Stochastic Context-Free Grammars (1.5 hour)
  16. 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:

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).



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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