BIOL367/F10

BIOL/CMSI 367-01/HNRS 398-05: Biological Databases

This is the home page for the Fall 2010 Biological Databases course at Loyola Marymount University while the computer science server is down.

You may also want to visit the Dahlquist Lab pages while you are here.

Week 7 In-class Exercise and Journal Assignment

Background Readings

1. Brown PO and Botstein D. Exploring the new world of the genome with DNA microarrays. Nat Genet. 1999 Jan;21(1 Suppl):33-7. DOI:10.1038/4462 |

   Brown & Botstein (1999) link to full text

2. Chapter 4 of Campbell & Heyer, Discovering Genomics, Proteomics, and Bioinformatics. Available on MyLMUConnect under the "Information" section.

Overview of Microarray Data Analysis

This is a list of steps required to analyze DNA microarray data.

1. Quantitate the fluorescence signal in each spot in the microarray image.
   • Typically performed by the scanner software, although third party software packages do exist.
   • The image of the microarray slide and this quantitation are considered the "raw-est" form of the data.
   • Ideally, this type of raw data would be made publicly available upon publication.
   • In practice, the image data is usually not made available because the raw image file of one slide could be up to 100 MB in size.
   • Also, some journals do not require data deposition as a requirement for publication, so often published data are not actually available anywhere for download.
   • Microarray data is not centrally located in a single database. Some major sources are:
     • NCBI GEO
     • EBI ArrayExpress
     • Stanford Microarray Database
     • PUMAdb (Princeton Microarray Database)
     • In addition, microarray data can sometimes be found as supplementary information with a journal article or on an investigator's own web site.
2. Calculate the ratio of red/green fluorescence
3. Log₂ transform the ratios
4. Normalize the log ratios on each microarray slide
5. Normalize the log ratios for a set of slides in an experiment
6. Perform statistical analysis on the log ratios
7. Compare individual genes with known data
8. Look for patterns (expression profiles) in the data (many programs are available to do this; we won't be doing this in class)
9. Perform Gene Ontology term enrichment analysis (we will use MAPPFinder for this)
10. Map onto biological pathways (we will use GenMAPP for this)

Analysis of Vibrio cholerae Microarray Data

• For the next section of the course, you will be introduced to the process we will use for the final projects in the course in a series of in-class and journal assignments where we will first analyze microarray data from Vibrio cholerae, and then learn how to create a Gene Database for this organism.
• The detailed instructions for the microarray data analysis we will carry out can be found on this page.

Individual Journal Assignment

• Store this journal entry as "username Week 7" (i.e., this is the text to place between the square brackets when you link to this page).
• Create the following set of links.
  • Link to your journal entry from your user page.
  • Link back from your journal entry to your user page.
  • Link to this assignment from your journal entry.
  • Add the "BIOL367/F10" category to the end of your wiki page.

Journal Club Articles

1. Salomonis N, Hanspers K, Zambon AC, Vranizan K, Lawlor SC, Dahlquist KD, Doniger SW, Stuart J, Conklin BR, and Pico AR. GenMAPP 2: new features and resources for pathway analysis. BMC Bioinformatics. 2007 Jun 24;8:217. DOI:10.1186/1471-2105-8-217 |

   Salomonis et al. (2007) link to full text

2. Doniger SW, Salomonis N, Dahlquist KD, Vranizan K, Lawlor SC, and Conklin BR. MAPPFinder: using Gene Ontology and GenMAPP to create a global gene-expression profile from microarray data. Genome Biol. 2003;4(1):R7. DOI:10.1186/gb-2003-4-1-r7 |

   Doniger et al. (2003) link to full text

3. Heidelberg JF, Eisen JA, Nelson WC, Clayton RA, Gwinn ML, Dodson RJ, Haft DH, Hickey EK, Peterson JD, Umayam L, Gill SR, Nelson KE, Read TD, Tettelin H, Richardson D, Ermolaeva MD, Vamathevan J, Bass S, Qin H, Dragoi I, Sellers P, McDonald L, Utterback T, Fleishmann RD, Nierman WC, White O, Salzberg SL, Smith HO, Colwell RR, Mekalanos JJ, Venter JC, and Fraser CM. DNA sequence of both chromosomes of the cholera pathogen Vibrio cholerae. Nature. 2000 Aug 3;406(6795):477-83. DOI:10.1038/35020000 |

   Heidelberg et al. (2000) link to full text

4. Merrell DS, Butler SM, Qadri F, Dolganov NA, Alam A, Cohen MB, Calderwood SB, Schoolnik GK, and Camilli A. Host-induced epidemic spread of the cholera bacterium. Nature. 2002 Jun 6;417(6889):642-5. DOI:10.1038/nature00778 |

   Merrell et al. (2002) link to full text, dataset (on this wiki)

Groups

TBA

Preparation for Next Week's Journal Club

In preparation for the Journal Club, each individual will do the following assignment on their individual Week 11 Journal page.

1. Make a list of at least 10 biological terms for which you did not know the definitions when you first read the article. Define each of the terms. You can use the glossary in any molecular biology, cell biology, or genetics text book as a source for definitions, or you can use one of many available online biological dictionaries. List the citation(s) for the dictionary(s) you use, providing a URL to the page is fine.
2. Write an outline of the article. The length should be the equivalent of 2 pages of standard 8 1/2 by 11 inch paper. Your outline can be in any form you choose, but you should utilize the wiki syntax of headers and either numbered or bulleted lists to create it. The text of the outline does not have to be complete sentences, but it should answer the questions listed below and have enough information so that others can follow it. However, your outline should be in YOUR OWN WORDS, not copied straight from the article.
   • What is the main result presented in this paper? (Hint: look at the last sentence of the introduction and restate it in plain English.)
   • What is the importance or significance of this work?
   • What were the limitations in previous studies that led them to perform this work?
   • What were the methods used in the study?
     • What samples did they collect and use for the microarray experiment?
     • How many microarray chips did they hybridize in the experiment?
     • Which samples were paired to hybridize on the chip?
     • Which was labeled red (Cy5)? Which was labeled green (Cy3)?
     • How many replicates did they perform of each type?
       • Biological replicates are made from entirely different biological samples.
       • Technical replicates are made when one biological sample is split at a particular stage in the procedure and then carried through to the end of the procedure.
     • What do they say about how they performed each of the steps listed in the Overview of Microarray Data Analysis section above?
   • Briefly state the result shown in each of the figures and tables.
   • How do the results of this study compare to the results of previous studies (See Discussion).
3. Upload your completed PowerPoint slides to your journal page by the Week 11 journal deadline (you may make changes before your presentation Tuesday morning, but I will be evaluating the presenttion you upload.)