Physiological consequences of ectopic agouti gene expression: the yellow obese mouse syndrome

This review summarizes primary and downstream phenotypic manifestations, wi th emphasis on altered responsiveness to environmental stimuli, of dominant yellow mutations at the mouse agouti locus. Obvious effects include hyperi nsulinemia, obesity, stimulation of somatic growth and tumorigenesis, and c oat color. Downstream influences of hyperinsulinemia and obesity on the ind ividual's physiology determine important components of the obese yellow ago uti mouse syndrome. Collectively, the phenotypic aberrations described supp ort the concept that identical genomes are expressed in a spectrum of physi ological phenotypes that reflect the complex interdependence of gene-regula ted physiological pathways and processes in the organism throughout extende d, but temporally ordered, periods of fetal and neonatal development and ag ing. This summary identifies important areas for additional research and pr ovides integrated information required for a systematic approach to the dev elopment of interventions for common adult human health problems.