22. a.) Make a diagram of an unduplicated chromosome containing two different genes, gene A and gene B. Use this diagram to explain gene locus and gene linkage.
b.) Why does gene linkage interfere with independent assortment?
c.) Suppose the genotype of an organism is AaBb. If the genes A and B are linked on one chromosome (as in part a, above), and their recessive alleles, a and b, are on the other homologue. (You should be able makes a diagram of meiosis to show how the gametes would be produced in the following questions.)
i.) How many different genetic types of gametes would be produced in the absence of crossover? List them:
ii.) If crossover occurs between the loci of the linked genes A and B involving the organism above (AaBb), how many different genetic types of gametes could be produced? List them and estimate the approximate ratio of the different genetic types of gametes and explain why those produced as a result of crossover occur much less frequently:
iii.) Suppose the genotype of an organism is AaBb. How many different genetic types of gametes would be produced if Genes A and B are not linked? List them: