Part 1: A New allele appears in crawfish population. Describe one factor that would most likely cause the frequency of the new allele to increase

Part 1: A New allele appears in  crawfish population. Describe one factor that would most likely cause the frequency of the new allele to increase over time?

Part 2: Suppose new mutation creates an allele that prevents juvenile crawfish from developing into adults. Describe how the future of the new allele in the population would be different depending on whether the allele is dominant or recessive?