Dr. Sing developed models for the relationships between the DNA sequence variation in the 13 candidate CVD susceptibility genes identified, measured, and characterized in Dr. Nickerson's and Dr. Weiss's projects and variation in established quantitative risk factors for CVD, including total plasma cholesterol, HDL cholesterol, and triglycerides, and systolic and diastolic blood pressure collected from the 1,500 individuals. His project established which subset of DNA sequence variations in which candidate genes were associated with variation in CVD risk factors in which subset of individuals and in which of three populations. His elucidation of the relationships between DNA sequence variations and variations in intermediate biological risk factor traits revealed opportunities for intervention to alter the risk of CVD and establish whether such efforts should be directed across populations, within a population, or at an individual.