Evidence for shared genetic programs from cluster analysis of hippocampal gene expression dynamics in development and response to injury

Cluster analysis is a computational method that groups together similarly-s haped patterns. It may be applied to large-scale gene expression data to fo rm new hypotheses regarding gene function. In the present study, we cluster ed the temporal expression patterns of genes expressed in the rat hippocamp us during normal development and after a kainate-induced seizure injury at postnatal day 25. We found that two different methods, Euclidean hierarchic al and K-means clustering, produced slightly different results, and conclud ed that different clustering methods may be used to complement one another. We also found that certain genes cluster together both during development and after seizure injury consistent with the idea of sets of genes that act in concert under various conditions.