Exercise 3 solution

import random

def linked_gamete(rng, r):
    if rng.random() < r:
        return rng.choice(["Ab", "aB"])
    return rng.choice(["AB", "ab"])

def estimate(rng, r, n):
    offspring = [linked_gamete(rng, r) for _ in range(n)]
    recombinant = sum(1 for g in offspring if g in ("Ab", "aB"))
    return recombinant / n

rng = random.Random(5)
for r in (0.05, 0.2, 0.5):
    est = estimate(rng, r, 100000)
    print(r, round(est, 3), round(abs(est - r), 3))

Output:

0.05 0.049 0.001
0.2 0.198 0.002
0.5 0.498 0.002

Reading it: counting the recombinant offspring recovers the true rate to within about 0.002 with 100,000 offspring. At 0.5 the genes are indistinguishable from genes on different chromosomes.