Figure 3. Heat map of clusters of genes differentially expressed during gametogenesis.

Hierarchical clustering obtained using Pearson’s correlation on the 32 unique transcriptomic profiles of gonads (columns). Clusters of the 2,482 differentially expressed genes (rows) have been obtained with k means clustering using Pearson’s correlation. Individual gonad samples from the same developmental stage and sex grouped together. St3: stage 3; St2: stage 2; St1: stage 1; St0: stage 0. Genes showing similar expression profiles clustered together. Four main groups are identified: stage 0: genes more expressed at early gonadogenesis stages (stage 0 and stage 1); Males and females: genes that vary in expression over the course of both male and female gametogenesis; Male: genes that increase in expression over the course of spermatogenesis; Female: genes that increase in expression over the course of oogenesis. Color represents the transformed normalized Cy3 log value obtained for each sample. The variations in transcript abundance are depicted with a color scale, in which shades of red represent higher gene expression and shades of green represent lower gene expression.