It is interesting to hear patients talk about having good or bad genes. People with a parent who lived to be 95 years often speak of the hope that they inherited the “good genes.” However, in some families, the males die of a massive myocardial infarction from coronary artery disease in their late 40s. What is the difference? The human APOE e4 gene discussed previously also facilitates the intestinal absorption of lipids and the efficient storage of fat in body tissue. While APOE e4 allowed humans to nutritionally survive to the age of reproduction, it increased heart attacks and strokes, a phenomenon known as antagonistic pleiotropy. However, about 200,000 years ago when H. sapiens emerged from Africa, an APOE e3 allele appeared that is found in 60-90% of currently living humans. This new allele was better suited to meat and fat rich diets and these individuals exhibit lower serum cholesterol, lower incidence of coronary artery disease, and decreased cognitive decline. On average, APOE e3 carriers live 6 years longer than APOE e4 carriers. Thus, APOE e3 could be considered a good gene.
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