Category: 08. April 8

Suegene Noh, Assistant Professor of Biology at Colby College, began her presentation on genomes shaped by evolution by looking at the social amoeba Dictyostelium dicoideum. In the case of the “dicty”, as she referred to them, amoebas are unicellular organisms, but they have the ability to aggregate and form mounds. In this process the dicty form a fruiting body with spores and a stalk in order survive harsh conditions, and in this form, they are able to eat bacteria. Organisms that have singular and multicellular stages have facultative multicellularity as it benefits the singular organism to band together with others of its kind for survival. However, when genetically different cells make up the same body their interests tend to be different. Human cells do not behave in this way because they are identical, but they do conflict in other ways such as cancerous cells, which have a very different agenda from normally developed cells. Professor Noh describe fruiting bodies with multiple different types of dicty as chimeric and she used those in her own research.

In her lab she has compared the ways in which chimeric dicty genes are expressed compared to those of clonal genes (fruiting bodies made up of one strain of dicty). In her research she used Illumina Cell machine to sequence the whole genome of the dicty mounds. She used four pairs of wild dicty strains and out of those made two clonal samples and one chimeric sample and repeated the study four times. She found that in the chimeric samples, sometimes they would produce less or more of certain genes compared to the clonal samples, and more frequently genes were biased down in chimeras. However, the few up regulated genes in the chimeric samples were involved in the development of the fruiting body and the cAMP response which is important for the aggregation of the Dicty. These changes in gene expression demonstrate that the chimeric genes selected for those that would help the fruiting body survive the best. This shows that the process of going through this cycle means that the chimeric samples will be more “fit” than the clonal samples.

Professor Noh used a second example to demonstrate the effects of social conflict on the evolution of the dicty. She discussed three types of microbes that infect the dicty and keep them from forming the fruiting bodies that allow them to survive. Each of the three types of bacteria interact with the host in a different way, but the dicty have evolved in different ways due to the social conflict that they have endured with either agricolaris, bonniea, or hayleyella. Some of the audience members asked why professor Noh chose to get the strains of dicty that she used from the wild. She explained to the roome that some of the dicty strains that are grown in the labs have been effected by the environment in which they were made, and by choosing to select strains from the wild she was able to improve upon the validity of her own research.

In last week’s lecture in the series: A Presence of the Past, Professor Suegene Noh gave a speech titled, “How Current Genomes are Shaped by Evolutionary Pasts”. A biology professor at Colby, Professor Suegene had a lecture much unlike many of the previous in the series. As other students have already noted concerning the methodology of the lecture, it was quite different from what we have seen already. Grounded in hard science and in a field that many in the lecture seem to have been well versed in (professors included), Professor Suegene still did a great job to ensure that those with less of a background in biology still had access to the material by means of thorough explanations when using technical jargon.

While I was unfamiliar with much of this topic prior to the lecture, and also would not consider myself proficient at all when it comes to the sciences, Professor Suegene brought up points about amoeba competition that connected more towards society than anything else even though the argument itself was based in hard science. It was interesting to consider that even at the smallest levels of life on this planet (ones at which the human eye cannot even see), there are some similar dynamics to the ones we see between individuals as well as communities in larger life forms.

Being in a field (art history) which focuses more on careful looking and research rather than experimentation, it was particularly interesting for me to learn a bit more about the research that Professor Suegene is conducting concerning dicty. It was incredible to learn about the adaptable nature of dicty, especially when considering the extent at which we have questioned humanities ability to adapt to other versions of change (both positive and negative) that we see in the current global scope.

One element of the speech that I found particularly interesting was Professor Suegene’s notation of the idea of “strength in numbers”. Thinking about the positive element of this idea when considering the research being done by Professor Suegene, it is also interesting and important to think of the negative ways this idea has come up in some of the past lectures. Even lectures concerning climate change and the detrimental changes to our environment that have been seen over the past decade, we can acknowledge ways in which the presence (or lack thereof) of numbers has changed the eventual outcome that the past has had on the presence. Also, notable, was the idea that social pressures influence even the most basic forms of biological life. As touched upon by classmates, this brings upon the conversation regarding the ability of genes to undergo changes due to social pressures. While this idea is remarkable to think about, when reflected upon it really does make sense and Professor Seugene is correct in noting that it is often acts of social oppression that result in dominant changes to certain life forms genes. Overall, while much of the hard science made this lecture a bit more difficult to follow, the points regarding the biological processes of the past affecting the present rang true and stayed very in line with the topic of our lecture series.

Professor Suegene Noh discussed her research in her talk entitled, “How Current Genomes are Shaped by Evolutionary Pasts”. Despite covering fairly complex material, I really appreciated Professor Noh’s effort to make the content accessible to a range of audiences. Additionally, as an environmental science major, my previous coursework helped prepare me to understand her lecture. Dr. Noh’s research focuses on Dictyostelium discoideum, a social amoeba,  found in soil. The “dicty” aggregate into slug shaped forms during the winter. About 20% of the dicty at the head of the aggregation die while the other 80% turn into spores. She used genomic sequencing to compare the mRNA abundances of each gene sample from clonal samples and wild samples. By comparing chimera based up and chimera based down samples Dr. Noh found evidence to support her claim that the dicty positively select traits through evolution rather than through neutral evolution. She further studied the endosymbiotic relationship between dicty and Burkholderia. She found that over evolutionary time the more closely associated the burk and dicty become, they show distinct differences as a result of their relationship.

It’s fascinating to apply the theme of the presence of the past to scientific findings. Many of the other lectures in this series have focused on either the social sciences or literary studies. Over time, scientists like Dr. Noh have identified evidence supporting evolutionary and adaptive changes over time. Thus, the historical origins of older species are present in a changed/evolved way today. It’s really incredible to see how adaptive organisms can be to their environments. The fact that the dicty she studied changed in size as a response to their relationship with the burk is pretty amazing- especially given the relatively short time period considered (compared to geological time scales of millions and billions of years). The effect of the historical origins and treatments was really highlighted by Chris Walker’s question. Professor Walker asked about Dr. Noh’s motivation for studying wild dicty. She explained that many scientists use lab grown/cultivated samples of dicty but, these samples, over time, adapt to the lab conditions. By using a wild strain Professor Noh attempts to remove a specific bred, component of the past from affecting the results of her research. By removing a controlled component of the past Dr. Noh is able to better see the changes in the organisms she studies. However, she’s also able to use the existing research about those lab-grown dicty samples as a control in her research.

I was inspired by how modern, and groundbreaking Professor Noh’s research is. By using the fairly new study of genomics, Professor Noh is able to study the burk and dicty at an extremely precise level. Her research likely would not have been possible 20 years ago. It’s cool to know that such a  present and active field of research is being conducted on Colby’s campus.

In this discussion, Professor Suegene Noh outlined how microbial function can be related to social function in human groups. She outlined how selective pressures in an amoeba species can create cellular aggregations that improve the fitness of the individual amoeba cells. This talk is an interesting divergence from the general tone of these speakers’ topics, where the subject matter is much more rooted in anthropology, and topics less grounded in science. As a biology major, I obviously appreciated the topic compared to others, because it combines my foremost academic interest and some interesting commentary on social dynamics. Adaptation is biology’s interpretation of the past dictating the future, and when looking at microbial evolution, professor Noh was able to parallel this small scale evolution to themes of human advancement through conflict.

This talk proved how the phrase “strength in numbers” applies to all levels of life, and a phrase that has applied to all levels of conflict as well. Looking through human history, it has been consistently advantageous for humans to form groups, societies, among other forms of aggregation, and this has helped various societies improve their fitness and continue to move forward generationally. This aggregation and subsequent conflict not only aids in genetic evolution, but in addition, can go toward helping towards psychologically bettering humanity through adapting through these conflicts. By learning from previous experiences and conflicts, humans can apply adaptation to the way their societies are run.

Additionally, the theme of symbiosis is one that is incredibly important not only for our bodily function, but in a more macro sense, human community organization. Relationships between the human micro biome ensure that our bodies remain healthy and certain bodily functions can remain as efficient as possible. When looking at community organization, most societies are optimized with its people occupying different niche roles, and bettering the aggregate (the community in this example).

As someone who is more trained in STEM, the way I look at some anthropological and philosophical issues is through a scientific lens, which is why this talk was an important one for me to further understand the theme of the seminar. In terms of human advancement, there is no better concrete example than genetic advancement and evolution. Furthermore, as organisms have advanced over millions of years, social evolution has been a very important part of the development of life, not just human life. Phenomena such as mutualism, commensalism, and altruism to name a few are all social evolutionary developments that are found in organisms such as gut microbes as well as animals much larger.

Suegene Noh, an assistant professor of biology at Colby College, gave a lecture titled, “How Current Genomes are Shaped by Evolutionary Pasts” where she looked at how lives of organisms are shaped by their social interactions. Dr. Noh’s talk was definitely my favorite of the series so far- most likely because of my more scientific background. I think she did an incredible job linking the more specific scientific talk with the humanities. Additionally, her topic resonated the most regarding the presence of the past for me. Dr. Noh is an evolutionary biologist whose research focuses on how social interactions among microbial organisms shape their genomes. Additionally, these interactions affect how our genomes evolve so that current patterns of DNA sequence variation can be used to detect past evolutionary events. Dr. Noh took some time to explain how a social amoeba works and its microbial symbiont. As a specific example, she used how competitive interactions among amoebas has caused certain genes to evolve more rapidly, and how associating with an amoeba host may have caused symbiont genomes to shrink in size. Essentially, all of this is amoebas developing into multicellular organisms. The Dictystelium Discoideum “Dicty” social amoebae aggregate together, form little mounds, and the mounds elongate into slugs, which are multicellular organisms.

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