Question

genetic maps are based on recombination frequencies. because both odd and even numbers of crossovers can occur between any two gene loci, as the physical distance between two loci increases, the maximum recombination frequency levels off at 50%. however, suppose you discovered a species where only an even number of crossovers can occur between any two gene loci. in this case, as the physical distance between two loci increases, you would expect the maximum recombination frequency to

multiple choice

be zero.

level off at 75%.

level off at 25%.

increase with no limit.

level off at 50%.

Explanation:

Recombination frequency depends on crossover events: odd crossovers produce recombinant gametes, even crossovers (including 0) produce non-recombinant gametes. Normally, odd/even crossovers are equally likely at large distances, leading to 50% max recombination. If only even crossovers occur, 0 crossovers (non-recombinant) and even crossovers (also non-recombinant) are the only possibilities—so no recombinant gametes form.

Answer:

be zero.