Good Genes and Evidence of a Skinny Gene

It is fascinating for doctors to hear patients inquire about whether they inherited good or bad genes. Individuals with a parent who lived to be 95 years are usually optimistic that they inherited the “good genes.” Conversely, in some families, the males die due to a massive myocardial infarction from coronary artery disease in their late 40s. Which factors are responsible for such drastic variations?  The human APOE e4 gene enables intestinal absorption of lipids and the efficient storage of fat in body tissue. While APOE e4 allowed humans to nutritionally survive to reach the the age of reproduction, it caused heart attacks and strokes, a phenomenon known as antagonistic pleiotropy; however, about 200,000 years ago when Homo Sapiens emerged from Africa, an APOE e3 allele appeared that is present in 60-90% of currently living humans. This new gene evolved to metabolize meat and fat rich diets and these individuals demonstrate lower serum cholesterol, lower incidence of coronary artery disease, and minimal cognitive decline. APOE e3 carriers typically live 6 years longer than APOE e4 carriers; therefore, APOE e3 can be deemed a good gene.

Many patients wonder why some individuals are prone to gain more weight than others. This had led medical researchers to search for the presence of a “skinny gene,” but, alas, none has ever been discovered. There is some evidence that specific bacteria in the gut are capable of promoting increased caloric absorption and the gut bacterial flora may be genetically controlled. Yet, “skinny” gut bacteria are not commercially accessible…Varying body fat inclination might be directly related to dietary animal fat absorption. Several genes possess the capability to absorb more lipids through the gut than others, such as the APOE e4 gene. Numerous human genes compensating for increased use of dietary materials have been highly coveted given that adequate food has been a constant struggle for man. Recently, copious amounts of food have become plentiful and the capacity to efficiently use every possible calorie has become a drawback, not an advantage.