In loppins (small, diploid invertebrates), chocolate-dependent problem-solving ability is an autosomal recessive trait. you have been hired to map the position of the gene controlling this phenotype (called "lu") using two simple sequence repeat markers (called "a" and "b"). you first cross two pure-breeding loppins:
lu+ a[3 repeats] b[5 repeats]/lu+– a[3 repeats] b[5 repeats] x lu– a[6 repeats] b[8 repeats]/lu– a[6 repeats] b[8 repeats]
the f1 is then crossed back to the lu– /lu– parent. which of the following results would indicate that the lu gene is much closer to repeat "a" than to repeat "b"?
a) lower proportion of a[3 repeats]b[5 repeats]/a[3 repeats]b[5 repeats] than a[3 repeats]b[8 repeats]/a[3 repeats]b[5 repeats] individuals
b) lower proportion of lu+ a[3 repeats]/lu– a[6 repeats] than lu+ a[3 repeats]/lu– a[3 repeats] individuals
c) lower proportion of lu+ a[3 repeats]/lu– a[6 repeats] than lu+ a[6 repeats]/lu– a[6 repeats] individuals
d) lower proportion of lu+ a[6 repeats]/lu– a[3 repeats] than lu+ b[8 repeats]/lu– b[8 repeats] individuals
e) lower proportion of lu+ a[6 repeats]/lu– a[6 repeats] than lu+ b[8 repeats]/lu– b[8 repeats] individuals