Writing in Biology

The ability to perform early, non-invasive prenatal tests such as the Harmony Test is due to the discovery of cell free fetal DNA (cffDNA). As the name implies, cell free DNA can be found free floating in the bloodstream. In the blood of a pregnant woman, both maternal cell free DNA and fetal cell free DNA can be found in the mother's blood. The fetal DNA comes from trophoblastic cells, the cells on the outer layer of a blastocyst. Some of these trophoblastic cells go through apoptosis (programmed cell death), and the DNA can end up in the mother’s bloodstream. The fetal DNA is present in the mother’s blood after five to seven weeks of gestation, and the amount of cffDNA present increases as the pregnancy continues. One challenge of studying the cffDNA is that the majority of the free DNA in the bloodstream is maternal, not fetal. In order to accurately assess the karyotype of the fetus, it must be possible to analyze the fetal DNA without any of the maternal DNA. The ratio of maternal cfDNA and fetal cfDNA can vary greatly between each individual, with some reports claiming 3-6% of the DNA being fetal and others claiming 11-13.4% being fetal. The major difference allowing for differentiation between the two sources of DNA is that fetal DNA segments are around 200 base pairs long, which is significantly shorter than the maternal DNA fragments. To collect the DNA, the blood sample from the mother is spun down in a centrifuge to separate out the plasma, from which the cffDNA can be isolated and purified via methods such as PCR or use of a mass spectrometer.

Both articles are structured in a similar matter, they start off with the title which identifies the topic of the article. Followed by the Abstract. In the abstract, they both give a brief background/summary of the topic, or argument, that they will discuss in the paper. This sections is to give a very brief explanation of the subject to give the reader an understanding of this subject, this can almost relate to the synopsis on a book.

The introduction is next. In the introduction, they elaborate more on the subject matter. The first paragraph of the this section serves to illustrate the key concepts of the topic, for example in the Baltic Sea article, it talks about how there is an acceleration in the global exchange of aquatic species to due human activity. In the article on the pool of native and non-native species, it mentions how the non-native species have been increasing in different ecosystems around the world. The introduction is in much more detail than  the abstract, in this section they begin to pull in the discoveries, and comments from other scientists who have studied related topics and use those as a base for the project. It is structured in a way that it goes from the broad subject topic and gets more in depth to the problem as it goes eventually ending in the hypothesis or something they want to achieve in the paper. The last paragraph of the introduction being either what they hypothesis or are trying to prove/convey in their piece. This section is to give a deeper understanding, some viewpoints, and what is going to be tested/talked, or what they want to achieve about in the piece.

The larva that was observed in class was tan in color with a short stalky body and a long brown tail. The organism moved in an undulatory fashion sending a wave down the length of its body in order to propel it forward. The skin of the larva was stretchy and translucent allowing the observer to look into the organism's body. When looking inside the larva you could see some white masses and brown or black masses, which could be a number of interior organs. Because of how the larva moved and that it also had trouble climbing it is safe to assume that the organism is terrestrial and would be found running around on the forest floor. The diet of the larva is unknown due to a lack of resources in the research area. If studied for longer than more information could be gathered for this small insect larva. 

In Your Inner Fish, An entire chapter is devoted to teeth. Teeth are incredibly useful when studying fossils because they are hard features that easily fossilize. In fact teeth are sometimes the only hard parts of animals to fossilize. Shubin includes personal anecdotes regarding his search for fossils, including finding some of the earliest known specialized teeth. Shubin does not only talk of his incredible fossil discoveries, but also the entire history of life. There are numerous reasons as to why it took so long for multicellular life to proliferate. Firstly, the conditions must be right, the environment must be suitable for life and contain enough oxygen to meet energy demands. Multicellular life takes significantly more energy than unicellular life.

The coyote Canis latrans, wolf Canis lupus, and domestic dog Canis familiaris are all separate species.  The three species have been known to interbreed with one another in very scattered populations around the united states. Some northeastern coyotes have been shown to have percentages of both domestic dog and the wolf showing solid evidence towards the three species interbreeding. The idea that the inability to breed with other species should be removed from defining what a species is using this coyote hybrid as a great example. The northeastern coyotes show evidence of gene flow and while it is similar to hybridization these coyote hybrids are not a separate species. These hybrid coyotes should not be seen as a perfect example of gene flow and how an animal may adapt the changing environment.

    Of course, the science and technology seen in the movie are works of fiction. In reality, while we are making great advances in the field of genetic testing, we are still nowhere near being able to do what is shown in the film. As discussed in class, prenatal genetic tests are rising in popularity, being used to detect certain genetic abnormalities. However, these tests are nowhere near the level of the tests in the film. We are able to detect large abnormalities such as a trisomy, but small things like controlling hair color, height, etc. are not able to be manipulated. In some cases, it is unclear which genes end up contributing to a certain trait. A lot of research into what DNA sequence causes certain traits would need to be performed before any test of that level could be reached.

Sharks are well adapted to the marine environment and habit all latitudes from shallow water to the abyssal pit.  There are several adaptations that allow them to swim without expending too much energy and enable them to maneuver quickly and with agility. The bodies of most shark species taper to points at both the snout and the tail, increasing their hydrodynamics as they chase after prey.  They also have a type of scale known as a denticle, which controls the flow of water over the skin’s surface leading to a reduction in drag and more efficient swimming.    All sharks have a skeleton composed entirely of cartilage, which prevents it from sinking due to its lack of a swim bladder.  Unlike most vertebrates, they do not rely on their internal skeleton to provide them with firm sites for muscle attachment.  Instead, sharks have a thick skin composed of a meshwork of strong and flexible collagen fibers.  This woven layer acts as a receptacle for swimming muscles to attach directly to their armor-like skin.  From a mechanical perspective, having muscle directly attached to an external skeleton is a very efficient arrangement, resulting in very little waste of muscular energy.  Sharks use low energy and mechanically complicated movement, which allows for continued existence as an apex predator.  The study of shark swimming adaptations, which have allowed them to be evolutionarily unchanged from millions of years, could be implemented in future boats and submarines.  

The ability to perform early, non-invasive prenatal tests such as the Harmony Test is due to the discovery of cell free fetal DNA (cffDNA). As the name implies, cell free DNA can be found non-encapsulated in the bloodstream. In the blood of a pregnant woman, both maternal cell free DNA and fetal cell free DNA can be found. The fetal DNA comes from trophoblastic cells, the cells on the outer layer of a blastocyst. Some of these trophoblastic cells go through apoptosis, and the DNA can end up in the mother’s bloodstream. The fetal DNA is present in the mother’s blood after five to seven weeks of gestation, and the amount of cffDNA present increases as the pregnancy continues. One challenge of studying the cffDNA is that the majority of the free DNA in the bloodstream is from the mother. In order to accurately assess the karyotype of the fetus, it must be possible to analyze the fetal DNA without any of the maternal DNA. The ratio of maternal cfDNA and fetal cfDNA can vary greatly between each individual, with some reports claiming 3-6% of the DNA being fetal and others claiming 11-13.4% being fetal. The major difference allowing for differentiation between the two sources of DNA is that fetal DNA segments are around 200 base pairs long, which is significantly shorter than the maternal DNA fragments. The blood sample from the mother is spun down in a centrifuge to separate out the plasma, from which the cffDNA can be isolated and purified via methods such as PCR or use of a mass spectrometer.

This review, authored by Dr. Hingorani and Dr. Gierasch, aims to link fundamental research regarding in vitro and in vivo protein folding in an evolutionary context. Since RNaseA was first denatured and re-folded sixty years ago, studies regarding in vitro protein folding have advanced our understanding of the process of protein folding specifically of small fast-folding domains, which could shed light on their in vivo folding properties and function in large proteins and the proteome as a whole. Strides have also been made in understanding the purpose and nature of unfolded protein states in vitro. Despite tremendous advances in the understanding of protein folding in vitro, there are still so many factors manufactured by the cells diverse and adaptive environment that cannot be simulated in highly diluted conditions. Factors such as chaperone and degradation enzyme aided folding, co-translational folding, crowding/ protein-protein interactions are all vital factors that affect how a protein folds and can only exist in vivo.