1. Factual Knowledge

What I learned so far in BIOL 463 are the four major kinds of cis-regulatory elements found in eukaryotic genes. They are promoters, enhancers, silencers, and boundary elements/insulators.

I know I have learned this because I can draw a basic diagram describing their function. I understand that promoters appear right before the transcription start site, and are necessary for transcription to occur. Enhancers, on the other hand, are not necessarily needed and can be located distally or proximally from the gene of interest. Their function is to increase the rate of transcription. Conversely, silencers are DNA elements that decrease the rate of transcription—although, some would argue enhancers and silencers are sometimes interchangeable depending on the cell type/ state of the cell. Finally, I learned that boundary elements/insulators act as ‘shields’ to protect a segment of DNA from the effects of other cis-regulatory elements or chromosome-packing proteins.

2. Conceptual knowledge

The past week, I learned how dorsal affects the formation of the D-V system in Drosophila. I learned that a loss-of-function mutation in the dorsal gene will cause ‘dorsalization’ because no gastrulation will occur, whereas a gain-of-function mutation in the dorsal gene will cause ‘ventralization’ wherein there is gastrulation everywhere.

I know I have learned this because I can explain the mechanism of function by which dorsal mutations cause dorsalization.  The gene dorsal encodes for a protein called Dorsal, which is present in the cytoplasm of all embryo cells, but has the ability to enter the nuclei of only ventral cells. The Pipe-Toll-Spaetzle pathway phosphorylates the protein Dorsal and allows it to break apart from Cactus so it can enter the nucleus of ventral cells only. In the nucleus, it acts as a transcription factor and promotes the transcription of genes necessary for VENTRAL development—that is, for gastrulation. That is why when there is not enough Dorsal on the ventral side (loss of function), no gastrulation occurs and dorsalization results. In contrast, if there was a gain-of-function mutation and Dorsal was found in the nuclei of too many cells, it would result in gastrulation everywhere—also known as ventralization.

3. Skills

One of the skills have I learned so far in BIOL 463 is how to interpret Drosophila development data and make correct statements about what the data means. Previously, I was unsure about how far I could interpret the data and what limitations the data might have, but now I feel confident that I could describe, interpret, and make conclusions about pictures of Drosophila embryos .

I know I have acquired this skill because I have learned from my mistakes on my quiz. On the quiz, I was unsure how I should interpret the different time frames and different distributions of light/dark. I now know to interpret data in its ENTIRETY, including the different time frames (which I had not done previously) and to not get caught up on what I think the data ‘should’ look like. I was trying to over-interpret the data on my quiz, and now I have realized what it means to make conclusions only on the data provided. Hopefully, my evidence for me learning this skill will be evident on the midterm!

4.  What is Factual Knowledge useful for?

I think factual knowledge is useful for being able to describe things, events, or concepts in a succinct and effective way. Terminology, for example, is factual knowledge that is incredibly useful for describing events without having to explain every piece of the event. With terminology, I am able to tell tell you that “the Dorsal protein causes gastrulation when it enters the nuclei of ventral cells because it acts as a transcription factor for proteins involved in gastrulation” without having to also explain what ‘protein’, ‘gastrulation’, ‘ventral’, or ‘transcription factor’ means. Thus, while factual knowledge does not allow people to make inferences or interpret data, it does allow them to describe it.