Figure 2
From: Identification of Schistosoma mansonigender-associated gene transcripts by cDNA microarray profiling
Measurement of adult S. mansoni male and female gene expression using cDNA microarrays was highly reproducible. (a) S. mansoni cDNA microarrays were constructed on glass slides in a format consisting of eight individual subarrays (arranged in four rows by two columns). Each subarray consisted of 144 DNA elements (arranged in 12 rows by 12 columns) with each DNA element being spotted twice (6 rows by 12 columns) within each subarray (indicated by brackets). Images were obtained by hybridization of Cy5-conjugated male cDNA and Cy3-conjugated female cDNA. (b) Analysis of subarrays 3 and 4 from five independent hybridization experiments (Hyb 1-Hyb 5) demonstrated consistent patterns of gene expression in adult male and female parasites. In experiments 1-4, male parasite cDNA was labeled with Cy5 (red) and female parasite cDNA was labeled with Cy3 (green), whereas in experiment 5, the fluorescent dyes were switched. (c) Statistical analysis of intra-array variation (comparing the natural log converted calibrated ratio from one DNA element to the natural log converted calibrated ratio of its corresponding duplicate DNA element for one representative experiment) demonstrated high reproducibility and tight associations between duplicates. The median coefficient of variation (CV = 11.1%) and the correlation coefficient (r = 0.91) indicated a high degree of agreement. (d) Statistical analysis of inter-array variation (comparing the mean natural log converted calibrated ratio of each DNA element in one hybridization experiment to the mean natural log converted calibrated ratio of the same DNA element in a second hybridization experiment) indicated a high degree of association between measurements and high reproducibility. The median coefficient of variation (CV = 14.4%) and the correlation coefficient (r = 0.90) supported this contention. Dashed lines in (c) and (d) represent the line of symmetry. The remaining solid lines in both (c) and (d) represent the regression line and the predicted 99% confidence intervals of the supplied data.