Synthetic Biology Vs. Natural Selection

New York Times Project

Biology 113

Topic: Synthetic Biology vs. Natural selection

 

Synthetic Biology vs. Natural Selection

Darwin first introduced the idea of evolution in his publication of The Origin of Species, on November 24th, 1859 (Campbell, 2005, p. 438). This opposed many traditional views as it was generally accepted that the beginning inhabitants of the world had no mutations in their genetic composition. His publication had two major points. The first being the modern organisms presently inhibiting the earth, differ from their ancestral species by a process called evolution. The other point he made was that of natural selection, as it is the mechanism for evolution. The organisms inherit traits from ancestors who were able to survive specific environmental conditions, passing these traits on to their offspring.

Darwin's revolutionary way of thought has led the way to discoveries in the field of evolution, becoming one of the fundamental concepts of modern biology. Many scientists design experiments illustrating Darwin's theory, as they tamper with the environment of the organism and watch it differ from one generation to the next. Other scientists move past the observation stage and start tinkering with the genetic composition of the individual organism, documenting its effects. This can be seen in bacteria and other microorganisms as scientists insert genes into the bacteria, altering the behavior. This can be made possible since the genetic code is universal, with commonalities within organisms of varying complexities. The fact that there lie common codons such as RNA's "CCG" is translated as the amino acid proline in all organisms (Campbell, 2005, p. 314). This leads us to the following articles as synthetic biologists explore the realm of genetic mutations as well as experiment with varying mutations as generations evolve.

In the first article, Carol Kaesuk Yoon explores the idea of evolution and its products, giving the world its diversity. She introduces the idea of a field in biology known as "evo-devo" (Yoon, 2007) (evolution and development). Instead of having many mutations of many new genes, but rather it's the mutation of a selected number of genes, as they are merely tweaks of existing genes. The classical outlook on evolutionary theory looks at the survival of the fittest while in evo-devo looks at it in a different sense, as they believe it is the arrival of the fittest. (Yoon, 2007). This article then explores the many different mutations seen in the world, as the first example is that of Darwin's famous observation of the finch. In the study shown, a number of beak sizes as well as beak strength found that two types of genes when expressed create different characteristics, such as "BMP4 gene," producing "BMP4 protein which signals cells to begin producing bone. This protein has led to the production of "wider, taller more robust beaks" (Yoon, 2007). Another gene however, Calmodulin, encourages a longer beak. Scientists have found that a large number of characteristics can be derived from just these two genes alone. This same gene is found in a number of organisms, altering their jaw type in a fish, lizards, rabbits etc. This gene confirms the main idea that "new forms can arise via uses of existing genes to oversee development" (Yoon, 2007), as you take existing genes and modify them in order to produce a different species. This is seen in many different species and the article goes on to explain how these mutations occurred by the change in certain DNA regions.

The second article just reinstates what was previously seen in the many organisms observed in the articles' experiments. In this article, however, only one experiment was conducted over a span of 18 years, breeding 12 lines of bacteria with over 40,000 generations. This experiment gives a direct link the idea of natural selection and evolution theory Darwin had in 1859. The experiment started by taking bacteria bred from a single E. coli and introduces it to a number of different environmental conditions. Dr. Lenski, the leading scientist on this experiment placed 12 identical lines in 12 separate flasks. His first condition was that of a meager diet of glucose. This has led to a decreased amount of bacteria, leaving the survivors. The survivors are then taken from the flask and moved to another flask, as this is natural selection, which allowed the bacteria to live and pass on their traits to offspring. Dr. Lenski also froze some of the bacteria so he could compare his newly evolved bacteria to the older versions. He has seen that the bacteria are now faster at reproducing. Dr. Lenski also saw a lot of notable similarities, as he says "we've found a lot of parallel changes" (Zimmer, 2007). Another experiment conducted was tampering with the temperature they grew up in. He saw that 2/3 of the lines did worse in high temperatures in comparison to their ancestors as he conditioned them to a cold environment. Another experiment identified in this article is that of a scientist, Paul Rainey identified the different ways in which a bacterium obtains nutrients. The bacteria floats in the broth as it fed on the nutrients provided. However within generations, some of its offspring mutated, taking up new ways of life, as it formed a "fuzzy carpet" (Zimmer, 2007), taking in oxygen and food from below. Somehow the bacteria on the bottom are killing off the ancestral floating microbes, as they cut off the oxygen. Another significant experiment done by Dr. Velicer grew bacteria in a rich broth, where they originally swarm to form spores, which kept them alive when the food was scarce. When he changed the broth, all of the offspring died out since they

...