Draw i t assume you are mapping genes a, b, c, and d in drosophila. you know that these genes are linked on the same chromosome, and you determine the recombination frequencies between each pair of genes to be as follows: a–b, 8%; a–c, 28%; a–d, 25%; b–c, 20%; b–d, 33%. (a) describe how you determined the recombination frequencies for each pair of genes. (b) draw a chromosome map based on your data.