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BI420 – Introduction to Bioinformatics. Gene Expression Analysis. Gabor T. Marth. Department of Biology, Boston College marth@bc.edu. Gene expression. Why study gene expression?. Which genes are active. at different developmental stages? in cells of different tissues?
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BI420 – Introduction to Bioinformatics Gene Expression Analysis Gabor T. Marth Department of Biology, Boston College marth@bc.edu
Why study gene expression? Which genes are active • at different developmental stages? • in cells of different tissues? • at different time points in the same cell? • cells under different environmental conditions? • between normal and cancerous cells?
Expression microarray movie DNA microarray chip animation: http://www.bio.davidson.edu/Courses/genomics/chip/chip.html
Time course experiments Experiment: measuring gene expression as oxygen gets depleted in yeast grown in a closed container
Data analysis – normalization • balance fluorescent intensities of two dyes • adjust for differences in experimental conditions
Log2 transformation Double or half expression now has the same magnitude
Clustering – intro • Why: if the expression pattern for gene B is similar to gene A, maybe they are involved in the same or related pathway • How: Re-order expression vectors in the data set so that similar patterns are together
Next two classes Chapter 7. Chapter 8.
Protein identification Protein separation by 2D gel eletrophoresis
Protein identification mass spectrometry
Protein function identification protein chips: identification of proteins that bind specific chemicals
Thanks Expression informatics slides courtesy of: Olga Troyanskaya, Ph.D. Department of Computer Science Lewis-Sigler Institute for Integrative Genomics Princeton University