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Overview of Affymetrix GeneChip technology. An Affymetrix GeneChip microarray consists of a 1.28 cm2 glass square which is divided into a grid of about 400,000 probe cells (each about 20 24 mm x 20 24 mm). Each probe cell contains about 106 copies of one specific 25-mer oligonucleotide.There
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1. RNA sample and array quality checking and normalization
2. Overview of Affymetrix GeneChip technology
5. Data file architecture in Affymetrix Microarray Suite
6. RNA sample quality checking
7. (3) Assessing RNA sample quality with the Agilent Bioanalyzer:
8. Assessing RNA quality with the Bioanalyzer
10. Array quality checking
12. Why we do log transformation of probe intensities
22. Checking array quality with histograms and q-q plots
28. Normalization/scaling
29. Normalization/scaling Differences in the overall intensities
of arrays can also be seen by
plotting histograms of the probe
intensities on a single plot (or the
log2 of the probe intensities):
The histogram of the abnormal bright
array is shifted to the right
Another array is also shifted to the
right, but to a lesser degree
30. Normalization/scaling
32. Normalization/scaling
35. Normalization to housekeeping genes
36. Normalization to housekeeping genes
37. Normalization to a reference RNA
38. Normalization to a reference RNA
39. Normalization in MAS 5.0
40. Scaling in MAS 5.0
41. Scaling/Normalization in MAS
43. Non-linear scaling
44. Non-linear scaling
48. Normalization in dChip
49. Conclusions
50. Which method of normalization is best?
51. Conclusions
52. Conclusions
53. Acknowledgements