Saturday, 7 April 2012

Epigenetics, the successor to Natural Selection?

                                                                                     Wayne Chiem 41966761

The study of evolution is regarded as one of the younger studies despite it being a timeless process. It wasn’t until around one and a half centuries ago that people had really began to think in depth about evolution and why certain organisms exist in today’s environment while others could not. The man responsible for this was Charles Darwin. When he presented his theories in the book On the Origin of Species, his ideas spread like wildfire. In a short amount of time, many of the world’s scientists started to praise Darwin and his findings (Eisley L. 1958). However, his research which led to his ideas was performed in the 1800s. How accurate could it have been without the sophisticated technology and advances in genetics we now rely on?

A team of researchers from the University of Adelaide’s “Australian Centre for Ancient DNA” abbreviated to “ACAD” believe that they have found the main driving force for evolution. The project director Alan Cooper claims “Epigenetics is challenging some of our standard views of evolutionary adaptation, and the way we think about how animals use and inherit their DNA.” (DNA holds clues to climate change adaptation 2012)

When explaining epigenetics, one may make the analogy that your genetic code is the tape, while epigenetics is the tape player. This is somewhat relevant as an organism’s epigenetics cannot change what has already been inherited from its parents. What it can do is decide which genes are expressed within individual cells, and to what degree. This is dependent on the environment it is brought up in. Researchers believe that to an extent, epigenetic information is also able to be passed down through generations. (Llamas B et al. 2012)

It was only in the last few decades where it became possible to analyse epigenetics. Using a method known as bisulfate sequencing, Alan Cooper’s research team analysed the ancient DNA of a 30,000 year old extinct bison and found similarities in its DNA methylation as those found in cattle today. This proved that epigenetic adaptation was inheritable and could remain long term. (Llamas B et al. 2012)

Figure 1: Thirty-thousand-year-old permafrost bison bones from the Yukon region of Canada. (The University of Adelaide 2012)

What gives more weight to this theory than natural selection is that it does not rely on thousands of years of random mutations within the genes. Under strong environmental pressure, such as rapidly changing climates during the formation of an ice age, certain genes can be switched off or on just as readily. The standard theory of evolution simply does not account for the fast changes that the history of the Earth has become familiar with (Didymus 2012).


The theory of evolution proposed by Darwin in the 1800’s was far from complete. Even he acknowledged that himself (Eisley L. 1958). With the growing interest in the field along with advancements made in technology, there is no doubt more will be uncovered about the other factors which contributed to this phenomena.


For further reading I recommend Digital Journal, where the link is provided below. The original research journal written by ACAD can also be found below under High-Resolution Analysis of Cytosine Methylation in Ancient DNA.



References:

Darwin C, 1859, On the Origin of Species by Means of Natural Selection, John Murray
 

Didymus JT, 2012, 30 000-year-old bison bone DNA yields new clues about evolution, Digital Journal: A Global Digial Media Network, viewed 10 March 2012,
<http://digitaljournal.com/article/318900>
 

Eisley L, 1958, Darwin’s Century: Evolution and the Men Who Discovered it, Doubleday & Co: New York, USA
 

Holmes B, 2012, Fossil DNA has clues to surviving rapid climate change, New Scientist, Reed Business Information Ltd., viewed 9 March 2012,
<http://www.newscientist.com/article/dn21410>


Llamas B, Holland ML, Chen K, Cropley JE, Cooper A, et al., 2012, High-Resolution Analysis of Cytosine Methylation in Ancient DNA, PLoS ONE 7(1): e30226.
<http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0030226>
 

Malik S, 2012, Climate insight in bison bones, news.com.au, viewed 17 March 2012
<http://www.news.com.au/climate-insight-in-bison-bones/story-e6frea6u-1226258851077>


University of Adelaide, 2012, DNA holds clues to climate change adaptation, The Jerusalem Post, viewed 10 March 2012,
<http://www.jpost.com/Health/Article.aspx?id=256405>

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