Why is the rate of evolution typically more rapid in segments of DNA that have no function?

• A. Because nonfunctional DNA is essential for the survival of the organism
• B. Because nonfunctional DNA is protected from environmental mutagens
• C. Because nonfunctional DNA is replicated more frequently than functional DNA
• D. Because mutations in nonfunctional DNA are less likely to be eliminated by natural selection

Answer: (D)

Verified step by step guidance

1. Understand the concept of natural selection: Natural selection is a process where traits that improve an organism's survival and reproduction are more likely to be passed on to the next generation. Mutations in functional DNA are often subject to natural selection because they can affect the organism's fitness.
2. Recognize the role of nonfunctional DNA: Nonfunctional DNA, often referred to as 'junk DNA,' does not code for proteins or have a known regulatory function. Mutations in these regions are less likely to impact the organism's survival or reproduction.
3. Analyze why mutations in nonfunctional DNA persist: Since mutations in nonfunctional DNA do not typically affect the organism's fitness, they are not eliminated by natural selection. This allows these mutations to accumulate over time.
4. Compare mutation rates in functional vs. nonfunctional DNA: In functional DNA, harmful mutations are often removed by natural selection, slowing the rate of evolution. In contrast, nonfunctional DNA can accumulate mutations more freely, leading to a faster rate of evolution in these regions.
5. Conclude why the rate of evolution is more rapid in nonfunctional DNA: The lack of selective pressure on nonfunctional DNA allows mutations to persist and accumulate, resulting in a higher rate of evolutionary change compared to functional DNA.