Evidence from animal studies has suggested that PFASs may be involved in altering energy metabolism and thyroid hormone homeostasis [15 — 17], likely through the activation of
various transcriptional factors, such as the peroxisome proliferator - activated receptors (PPARs)[18 — 20].
These include: a) Global Clusters that consist of a small, tight subset of genes that are co-expressed under the entire spectrum of experimental conditions; b) Time Series of gene expression profiles during successive days of standard ES cell differentiation; c) Specific Gene Classes based on hierarchical clustering of
transcriptional factors and ESTs; d) Expression Waves of genes with characteristic expression profiles during ES cell differentiation, juxtaposed to waves of genes that behave in the exact opposite way; e) Pathway Animations that illustrate dynamic changes in the components of individual KEGG signaling and metabolic pathways viewed in time - related manner; and, f) Search Engines to display the expression pattern of any transcript, or groups of transcripts, during the course of ES cell differentiation, or to query the association of candidate genes with
various FunGenES database clusters.