Suppose that in Mendel’s pea plants, you are studying two genes, C and D, located close together on the same chromosome. You cross together a CCDD plant with a ccdd plant. The F1 plants have the genotype CcDd. This plant will make four gamete types, but most of them will be CD and cd types. Why will it not make similar numbers of the four gamete types? What is the mechanism that produces cD and Cd gametes?

Principle of independent assortment

Explanation:

Here the concept of independent assortment comes into the picture.

According to the principle of independent assortment, in a dyhybrid cross or mutiallelic cross the number of different type of allele associated with different genes sort separately in order to form gametes with one allele from each gene. Or in other way it can be said that the receiving of allele of one form with in a gamete is not affected by the receiving of allele for another gene.  

Hence, genotyoe CcDd will produce for gamete – CD, Cd, cD, cd

there are no details given

explanation:

"1. it should be, it has been for about 20 years, and it's really not much different in the end than breeding animals to have particular traits. there are always concerns about genetically engineered animals/plants affecting the environment in unexpected negative ways, but i can't think of an example where the fears didn't turn out to be baseless.  

first, as you point out, it would be a great advance in pharmacology, to be able to tailor drugs and their doses to me. the pros involve better medical treatment. the cons involve privacy issues like insurance companies denying coverage to people with genetic risk factors. looking at dna markers wouldn't affect the frequency of genetic diseases, but it would allow detection of them earlier. and ok, actually i suppose that if people used this information to avoid having children with genetic diseases, some might decrease in frequency."