Posts Tagged ‘DNA’

When Charles Darwin wrote “On the Origin of Species”, he wrote about the difficulty of determining the actual mechanism of change in species from generation to generation. He was quite sure that the environment played a role in the final outcome of things via a survival of the fittest system. The problem in the theory of evolution was not that the strong thrive and the weak perish, because that is obvious. The problem is how does a species actually evolve? Darwin rejected the idea of incremental change over a long period of time as the likely cause of evolution. Instead, he looked at domesticated animals and observed how they could change over several generations by selective breeding. He thought that a mechanism similar to this, some sort of selective breeding that occurred in the wild, was the most likely mechanism of evolution. The “selective” breeding would occur between organisms that happened to be in the right place at the right time under the right conditions and they also happened to have the right genes for producing a successful hybrid. His theory was, in essence, that change in a species occurred due to a “natural” and chancy form of selective breeding. It wasn’t random change, it was more like lucky change. His theory then goes on to state the almost obvious: those changes that result in better adaptations to the environment result in better survival rates.

Darwin borrowed from the environmental theories of Malthus and concluded that as supplies of food increased in nature and animal populations thereby increased that those individuals most suited to the environment would prosper more than those who had been born slightly less suited. It was the principle of survival of the fittest. These survivors would then breed and the next generation would have the traits of the survivors. This was Darwin’s theory of evolution. The problem was, as Darwin admitted, how, exactly, does this generational change occur?

Many people take Darwin’s theory of evolution and proclaim that it is based upon random changes that occur in genes and those which help an organism to survive lead to successful adaptations while those random changes that hinder survival result in population declines. Darwin never advocated a theory of random change. His theory was more like a theory of natural selective breeding where the strongest get to breed and their traits are passed on to the next generation, very similar to what he observed in the farms of England.

Recently, genetic scientists have discovered that Darwin was wrong. It turns out that genetic change does not have to happen by selective breeding. It can happen by direct impact of the environment upon an organisms DNA. This new discovery states that the vast majority of our DNA, usually referred to as “junk DNA”, is not junk after all. Much of the human genome has been decoded so that we know where the code is in our DNA for blue eyes, or our blood type or even if we have a predisposition to some forms of cancer. Yet, the vast majority of our DNA is referred to as “junk”. That’s because scientists didn’t know what its function was – or if it even had a function.

In an article recently published in the New York Times , Gina Kolata writes that gene switches in junk DNA, “play critical roles in controlling how cells, organs and other tissues behave”. She states that, “…the environment can affect disease risk. In the case of identical twins, small changes in environmental exposure can slightly alter gene switches, with the result that one twin gets a disease and the other does not.” It stands to reason that if the environment can change junk DNA and then cause a disease, it can also cause a change that results in resistance to disease or perhaps some other very different result. The real discovery here is that a mechanism has been discovered that can cause human DNA to rapidly modify itself in response to a factor in the environment. This must be the cause of evolution.

While the Times article is primarily focused on diseases being caused by exposing junk DNA to certain substances, it is only reasonable to ask whether this is in fact the mechanism of evolution. It is a direct connection between the body’s genes and the environment. Certainly, there will be cases where the environment contains toxins and these toxins will harm the DNA and cause disease. However, this is very likely the mechanism of evolution also. It is the way in which the body’s DNA senses that the environment is changing and tries to make the appropriate response. This is very likely the true mechanism of evolutionary change. It also explains why evolutionary change is, as Darwin noted, fairly quick and not a progression of minute changes.

It seems that Darwin’s notion of selective change occurring because of the coincidence of the right circumstances for the right individuals is not the likely explanation for evolution. It seems far more likely that our “junk” DNA is not “junk” at all, and it is this DNA (it actually comprises about 90% of our DNA) that results in “evolutionary” change. It seems that just as we are able to make conscious adaptations to our environment that there is another level of consciousness in our bodies, that we are unaware of, that is also continually working to optimize our body’s response to the environment and also that of the next generation of human beings.

Junk DNA is how evolution works.


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Can a statement be true and untrue at the same time?  Yes, it can.  Take Thomas Jefferson’s famous “self-evident” statement that “all men are created equal”.  In the context that Jefferson was referring to when he was addressing the King of England, he meant that the colonists in America did not recognize that the King or any other members of the English royalty had any right by birth to rule over them.  In that sense everyone was equal.

However, in the literal sense, we are all born decidedly unequal. This is evident, more and more, as discoveries are made concerning genetic diseases.  Some of us are fortunate, and we are born, more or less healthy.  Others, less fortunate, suffer from inherited disease from the moment they are born.  Still others have inherited diseases that do not manifest themselves immediately but only appear later in life, such as certain forms of cancer.  All of these susceptibilities for particular diseases can be found in one place – our DNA.  Now, as more and more breakthroughs are made in biotech, companies like Myriad Genetics are able to create DNA tests to determine whether we are likely, or perhaps certain, to develop certain diseases as we get older.

The good thing about having the ability to analyze our DNA and see if we are likely to contract certain diseases is that some form of treatment can sometimes be started before the disease even appears.  We are about to enter a new age of medicine where newborn infants are routinely screened for a host of genetic diseases. Lifesaving steps can be taken while the disease still lies dormant in the baby’s DNA.  This, of course, is only the first step into a new realm of biology that will soon create a whole new set of questions that must be answered by those who would set our ethical bearings.

For example, it is well known that some people are born with bodies that produce mostly “fast twitch” muscle tissue in their legs, while others produce mostly “slow twitch” muscle tissue.  The fast twitch people are natural sprinters while the slow twitchers are more suited to running marathons.  Let’s suppose a child enters high school and decides to try out for the track team.  Let’s suppose the child wants to train for and run the 100 meters race; however, let’s also suppose that his DNA analysis shows that he will never be a competitive sprinter, no matter how hard he trains.  What should the track coach do?

Let’s suppose that, at some point in time, a structure in our DNA is discovered that promotes certain types of intellectual activity, such as music or art or mathematics.  It’s not impossible. There are well known cases of geniuses in the arts, like Mozart, who created magnificent music at a very early age.  Could this astonishing capability have all been taught by his father?  Maybe, but maybe not.  So, what do we do if more and more DNA research shows that we are all born with different gifts and capabilities, as well as different weaknesses.  Do we make use of such information starting from an early age or do we pretend that it isn’t real because we are all created equal?

We will soon have to contend with the fact that Jefferson’s statement was a statement of equality of rights and not literal physical or mental equality.  We have already entered the age when we can predict with high degrees of certainty which people will contract which diseases, just by examining their DNA.  The question we are about to face is this: do we hold on to “equality” with a religious fervor and refuse to go where no man has gone before, or do we boldly look at the facts encoded in our DNA, accept what is written there, and then decide to use that information for the benefit of all?

And the biggest question of all might be: Who will be the Decider?

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