Friday, April 9, 2010

Evolution Revised

Coyne's book is focused on explaining and proving what has been the accepted theory of evolution for more than a 100 years. Yet recent research has uncovered a kind of second genetic code in the form of epigenetics. Epigenetics, while not an actual genetic code, codes for the expression of genes in DNA. The interesting part of Epigenetics is that your epigenome can be altered within in a time span as short as one generation. In your opinion is the theory of evolution altered when viewed in the context of this new "genetic code"? Is it possible that we must write a new revised version of the evolutionary theory as more research is done in this area, or does the discovery of epigenetics simply clarify the workings of the body and either not effect or strengthen the argument of evolution?


  1. Theory will always undergo changes; certainly this is applicable to all sciences including biology. Newton’s theory of gravity wasn’t broken by the advent of quantum physics though quantum physics introduces particles and cases where gravity no long has an effect. Although we know little about epigenetics there is little evidence that it will destroy the theory of evolution or prove it for certain. What we do know is that epigenetics is somewhat comparable to identical twin siblings, they have the same underlying bodies and DNA but have (often times) completely different personalities. Epigenetics is the difference in how a gene is expressed from person to person when they have the same or similar genetic sequence. Occasionally the expression of a certain trait transcends the “Tabula Rasa” (Blank Slate) idea of traditionally epigenetics in which a trait, like the agouti fur color in mice, can be influenced by the 3rd generation above the current animal depending on environmental pressures and stresses. It is this type of transcending epigenetic expression that worries most staunch proponents of either side in the Intelligent Design vs. Evolution debate. On one hand ID supporters fret that this is the witness-able evolution within a single lifetime while on the other Darwinians feel that natural selection should take place over a very long period of time and a few generations should not produce any noticeable change simply due to the environmental stresses on their grandparents. Only time will tell the true nature of epigenetics and how it fits into the larger picture of molecular biology and the wonderful mosaic that is biophilia.


  2. In the article about Epigenetics that Mr. Erdmann gave us, "Why Your DNA Isn't Your Destiny" describes how Epigenetics could greatly influence the way that we view evolution. However, as mentioned by John Cloud, epigenetic markers in test subjects would eventually disappear (with a maximum of about 40 generations). While 40 generations of human lifespans may seem like a long time, imagine the time that evolution has been able to influence the emergence and divergence of new species. Looking at both classical evolutionary concepts as well as how epigenetics can easily change the ways in which our genes our expressed in less than 1 generation, the current model for how individuals are able to adapt to drastically changing environments. Looking at how fast epigenetics can affect and entire genomes expression, researchers perhaps could better understand how mammals were able to survive the extinction of the dinosaurs--perhaps it wasn't only because they were better suited for survival, but instead since they reproduced more often, it allowed a faster change in the epigenome, furthering survival of these creatures. Meanwhile, much further study of the epigenetics must be done, as much of the research pool is quite limited. Epigenetic research could lead to new medical solutions as well as a better understanding of human development, since our habits and behavior could directly affect our descendants, our decision are at a much higher stake.
    The biggest part about evolution is that it is very gradual. With the rapid change that epigenetics brings, evolutionary change might not seem as big of a deal as before. Epigenetic changes are affected by outside forces such as food sustainability, or climate, and may be just the key to how many species were able to survive massive extinctions that should have otherwise been wiped out with the classical view of evolution. Our once unchangeable DNA, set in stone, has become a pile of clay--easily manipulated by our everyday actions.
    Clearly, while in many ways the process of and especially the survival of certain species will definitely be changed by the rise of epigenetics, the role of evolution still serves as the backbone of our study of biology.

    Sources:,8599,1951968-2,00.html <-- Mr. Erdmanns article

  3. Coyne defines evolution as "(when) a species undergoes genetic change over time" (3). By that definition, the discovery of the epigenome does not require the statement to be amended because epigenetics does not present long term changes in a species. To prove this, this definition will be reconstructed into its basic elements. The first part of the sentence brings up a change in the genetic code. Although not everything is known about epigenetics, scientists do know that it deals with the activation and deactivation of certain genes. This is what allows a single totipotent stem cell to multiply and form all the different tissues within the human body. However, epigenetics does not actually alter the genetic code in most cases. The activation or deactivation of a gene effects the phenotype of the organism but the DNA of the gene is identical in both cases. With no genetic change being made, the genetic code, is still being passed onto the offspring. The later part of the definition says "over time". Epigenetics works on a very short time scale. Most epigenetic phenotypes are not multi-generational and most that are multi-generational are lost over several generations. The activation or deactivation of genes via epigenomes can be influenced by environmental factors, therefore, multiple generations in the same environment could have the same gene activated via epigenetics, but this would not be due to the parents' active genes but because of the common environmental factor between the parents and the child. Epigenetics allows for this reversible phenotype which aids in survival in the environment. If the environment would be more suitable with the the gene off, the organism can turn off the gene and survive with out the direct use of mutations. In this way, it controls the mutation rate. However, this is limited because the opposite use of the epigene will not always allow the survival of the species without mutations of the actual genome. The discovery of epigenetics, like its name, is above genetics. It allows in survival, but by the definition of evolution, does not play a role OVER TIME.