Which of the following contributes to the continuing evolution of new human pathogens?

• A. Genetic mutation and horizontal gene transfer
• B. Strict host specificity without cross-species transmission
• C. Lack of microbial reproduction
• D. Stable environmental conditions

Answer: (A)

Verified step by step guidance

1. Understand that the evolution of new human pathogens involves changes in the genetic material of microorganisms, allowing them to adapt and sometimes infect new hosts.
2. Recognize that genetic mutation refers to random changes in the DNA sequence of microbes, which can lead to new traits such as increased virulence or antibiotic resistance.
3. Know that horizontal gene transfer is the process by which microbes exchange genetic material with each other, even across different species, facilitating rapid acquisition of new capabilities.
4. Evaluate the other options: strict host specificity limits the ability of pathogens to infect new hosts, lack of microbial reproduction would prevent evolution, and stable environmental conditions reduce selective pressures that drive evolution.
5. Conclude that the mechanisms contributing to the continuing evolution of new human pathogens are genetic mutation and horizontal gene transfer, as these processes generate genetic diversity and adaptability.