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

Answer 1

In a species with single crossover per chromosome and no multiple crossovers, the recombination frequency would increase with the loci's physical distance, theoretically up to a 100% frequency, allowing a possibly more accurate reflection of physical distances in centimorgans on genetic maps.

Step-by-step explanation:

In a hypothetical species with only one crossover event per chromosome and no multiple crossovers, the recombination frequency between two loci would continue to increase as the physical distance between them increases. This trend would continue until it reaches a point where a crossover event is practically inevitable, which could theoretically approach a 100% recombination frequency if the chromosome is sufficiently long. This differs from organisms like Drosophila melanogaster, where multiple crossovers can happen, and the recombination frequency levels off at 50% due to the chance of double crossovers restoring the parental allele combinations. In calculating genetic distances, geneticists use recombination frequencies to derive map distances in centimorgans (cM), and in this scenario with single crossovers only, the map distances could more accurately reflect the true physical distances between loci on the chromosomes.