List the sub-stages during prophase i of meiosis, and describe the appearance/position of the chromosomes at each sub-stage.

Sub-stages during Prophase I of meiosis are: Leptotene; zygote; pachytene; diplotene and diakinesis.

Explanation:

In the sub-phase called leptotene, each chromosome is formed by two sister chromatids, where we can notice the presence of chronomers, which are small condensations.

 Talking about the zygotene sub-phase, the chromossomes begin to pair up, and this process is called synapse.

 The next sub-phase, called pachytene, each pair of homologous chromosomes has four chromatids, constituting one bivalent or tetrad, formed by sister chromatids and this is where the process called permutation or crossing-over occurs. Due to this process, we were able to visualize the chiasm under the microscope, which is nothing but an X cross.

 The next sub-phase called diplotene, homologous chromosomes begin to drift apart but remain linked by regions where permutation occurred and in this sub-phase we can see the chiasm regions better than tha phase before.

 In the last sub-phase called diakinesis, the condesation and separation of homologous chromosomes continue to happen With this, the chiasmas are sliding to the tips of the chromáids, a process called chiasma termination. As the phases evolve, the nucleolus and library disappear.

"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."

no i don't feel that humans have oversubscribed some medications