Question

Genetic maps are based on recombination frequencies. however, because some multiple crossovers produce parental rather than recombinant gametes, as the physical distance between two loci increases, the maximum recombination frequency levels off at 50%. but suppose you discovered a species where the location of each crossover event occurs at random but there is only one crossover per chromosome and no multiple crossovers occur. in this case, as the physical distance between two loci increases, you would expect the recombination frequency to?

a. increase with no limit
b. increase until it reaches 25%
c. increase until it reaches 75%
d. increase until it reaches 100%

Answer 1

In a species with only one crossover per chromosome and no multiple crossovers, the recombination frequency between two loci would increase until it reaches 100%, as each crossover would result in recombination.

Step-by-step explanation:

In the hypothetical scenario where a species has only one crossover per chromosome and no multiple crossovers occur, as the physical distance between two loci increases, the recombination frequency would increase until it reaches 50%.

This is because with only a single crossover per chromosome, every crossover would result in recombination, leading to a direct correlation between physical distance and recombination frequency. At lesser distances, the recombination frequency would be lower as the probability of a crossover occurring between the two loci would be less. Once the loci are far enough apart, the single crossover would almost always occur somewhere between them, resulting in recombination in nearly all gametes. Hence, the correct answer is (d) increase until it reaches 100%.