Final answer:
The chance that a neutral mutation will be lost due to genetic drift is initially the same as its allele frequency. Genetic drift is more likely to happen more quickly on an island due to smaller population sizes, which leads to greater susceptibility to random changes in allele frequencies as opposed to a mainland population where larger sizes buffer against such effects.
Step-by-step explanation:
The problem in question deals with the concept of genetic drift, which is a mechanism of evolution that involves a change in the allele frequency within a population due to random sampling of organisms. The probability that a neutral mutation will be lost due to genetic drift in a population of 100,000 is initially the same as its allele frequency, which in this case is 1/200,000 since the mutation starts in a single copy in one person. Because the mutation is neutral, the likelihood of it being passed on to the next generation is based solely on chance.
In relation to the given question, genetic drift would likely happen more quickly on an island than on the mainland. Islands typically have smaller populations and less genetic variability, which makes them more susceptible to the whims of chance in determining which alleles get passed on to the next generation. In large populations, like those often found on the mainland, genetic drift has a smaller effect because the larger number of individuals buffers against the randomness of allele frequency changes. However, the text presented discusses that a mutation's ultimate survival depends on complex factors, including population size, the specific mutation in question, and other environmental factors.
As to why genetic drift is more likely to occur on an island, small populations are more prone to fluctuations in allele frequencies due to the random loss of individuals carrying the genetic variant. If a mutation arises in a population of 10 individuals and one of those individuals dies before reproduction, 10% of the gene pool vanishes. In contrast, in a larger population of 100, the loss of one individual has a much-reduced effect, representing just 1% of the gene pool.