Question

Why could clean, sterile environments in modern life result in a rise in some genetic diseases such as Alzheimer's?

a. In sterile environments, antibiotics only kill the most harmful microbes.
b. Sterile environments are directly correlated with a high sugar diet and diabetes.
c. An increase in life span results in unmasking antagonistic pleiotropy.
d. Excessive cleanliness encourages the evolution of bacteria with new diseases.

Answer 1

The rise in genetic diseases such as Alzheimer's in sterile environments is associated with increased life span due to better hygiene and healthcare, which unmask negative effects of certain genes through antagonistic pleiotropy.

Step-by-step explanation:

The clean, sterile environments predominant in modern life contribute to an increase in some genetic diseases, like Alzheimer's, due to an effect known as antagonistic pleiotropy. Sterile environments themselves do not cause genetic diseases but may impact their prevalence indirectly.

Antagonistic pleiotropy suggests that genes which are beneficial in early life can have negative effects later on, hence 'antagonistic'. Since improved hygiene and medical care extend life span, genes that might otherwise not cause problems become important as they can contribute to age-related diseases like Alzheimer's. This implies that an increased life span due to sterile environments and advanced healthcare can inadvertently unmask the negative effects of these genes in an aging population.