Phase analysis of circadian-related genes in two tissues

摘要: Recent circadian clock studies using gene expression microarray in two different tissues of mouse have revealed not all circadian-related genes are synchronized phase or peak times across vivo. Instead, some may be delayed by 4–8 hrs one tissue relative to the other. These interesting biological observations prompt a statistical question regarding how distinguish from that systematically lagged phase/peak time tissues. We propose set techniques circular statistics analyze angles first estimate phases cycling separately each tissue, which then used paired angular difference differences modeled as mixture von Mises distributions enables us cluster into groups; group having transcripts with same tissues, other containing discrepancy between For we assess association types circular-circular regression. also develop bootstrap methodology based on regression model evaluate improvement fit provided allowing components versus one-component von-Mises model. applied our proposed methodologies common heart and liver Storch et al. [2], found an estimated 80% were phase, 20% about 8 hours heart. The p-value for being is 0.063, suggests possibility clusters. Our can extended more than example, kidney, heart, liver, suprachiasmatic nuclei (SCN) hypothalamus.