Mouse chimeras and their application to circadian biology.

Chimeric mice are versatile model systems for the study of mammalian circadian biology. In chimeras, genetically different cells are combined within single animals, making them useful for assessing how normal cells interact with genetically altered cells in intact biological systems. In particular, the primary circadian pacemaker in the suprachiasmatic nucleus is amenable to analysis using series of chimeras that incorporate cells carrying mutations in circadian genes. The study of chimeras carrying circadian mutations can contribute to a better understanding of the function of the altered genes and of the fundamental physiology of circadian timing. Chimera analysis is a valuable approach for studying network properties in complex, integrated biological systems like that which controls circadian behavior in mammals.