Final answer:
The scenario described is an example of pleiotropy, where one gene affects multiple traits.
Step-by-step explanation:
The scenario in which one gene is implicated in both lung capacity and high blood pressure in African Americans, as well as the risk of heart attack in European Americans, is an example of pleiotropy. Pleiotropy occurs when a single gene influences multiple phenotypic traits. This is distinct from polygenic inheritance, where multiple genes are involved in determining a single characteristic, such as skin color or height; codominance, where two different alleles are expressed at the same time; and epistasis, where the expression of one gene is suppressed by another gene.