A. Factual Knowledge

The first piece of factual knowledge I’ve learned the past few weeks is that X-inactivation differs in different species! I didn’t know that in mice, the paternal X gets reactivated only in embryo-proper cells, whereas in humans it gets reactivated everywhere. This was in comparison to Kangaroos who don’t reactivate it anywhere.

The second piece of factual knowledge I’ve learned is that there are multiple ways to inactive chromatin. I don’t have a huge genetics background, so I didn’t realize histone methylation, histone acetylation, and DNA methylation were all different things. I learned this from reading the midterm 2 paper, in which histone methylation can inactivate certain genes; acetylation can remove histones from that DNA; and DNA methylation tends to inactivate portions of the genome.

B. Conceptual Knowledge

I realized that there are many ways for chromatin to become ‘inactive’ and X-inactivation seems to use a different mechanism than normal imprinting! Imprinting is generally quoted as using DNA methylation to silence genes, and that these methylation patterns can be passed on parentally. However, X-inactivation seems to use histone modifications to establish parental source! I thought it was super interesting and found the reason for this that was proposed by the MT2 paper was really confusing.

C. Metacognitive knowledge

1. First, I read the paper as best as I could. I allowed myself to get confused. But, it allowed me to form a mental map of all the points the paper was trying to make. Next, I re-read it using google to clarify any questions I had. This allowed me to really understand the arguments they were making and fully comprehend what they were trying to say. Finally, I reviewed each figure without the accompanying text. I tested my understanding of the paper by being able to interpret the figures, and try to deduce what the authors were trying to say by just looking at their data.

2. The hardest part about this particular paper was its length. They made so many points and arguments that after a while, it got confusing to follow. Keeping track of PE vs IVF or 4-cell vs Morula vs Blastocyst was confusing enough, but reading 8 different arguments about them was even harder!

3. When I’m reading papers, I always feel most confident about interpreting what the authors have to say about their results. I enjoy reading about their ‘hypothesis’ or thoughts on strange results they got, and so I feel that I am confident in critically thinking about their proposed explaination or discussion. This was facilitated by me reading the paper several times and really scrutinizing the figures without the text. I think it gave me the opportunity to really look at the data alone, and then compare my own conclusions with the authors’.