Do we really need a new revamped theory of evolution?

A short answer to this meaty question is – NO?

But if you have been keeping a track of science news in the press recently, the half-baked articles all have this vague notion that an urgent extension is needed to the theory of evolution. And if you now ask why do we need such an extension, the answer invariably comes back as – EPIGENETICS.

In this summer we had a major controversy regarding the inadequate and completely wrong interpretation of epigenetics and gene regulation Siddarth Mukherjee’s article in The New Yorker based on his new book – The Gene: An Intimate History (Scribner, 2016). Apart from that, Royal Society conference hosted a conference on “New Trends in Evolutionary Biology: Biological, Philosophical, and Social Science Perspectives.” which harped on bringing a thorough revamp in evolutionary biology. And this was succeeded by a few articles like journalist Robby Berman’s Big Think,”How about a new theory of evolution with less natural selection?” and one by the eminent Carl Zimmer in Quanta Magazine as a longish essay, “Scientists seek to update evolution.”

So, what is this controversy about, who are the  “Third Way of Evolution” group and why despite all these claims evolutionary theory doesn’t require any sort of revision. This post discusses these issues and hopes that it would convince the readers that “All is well” with evolution.

The journos, and the “Third Way of Evolution” group  claim that the rising field of epigenetics is a way by which environment leads to long-lasting changes in the phenotype which can be inherited without altering the DNA sequences directly.epigenetic_mechanisms

These changes come somehow by the presence of methyl groups on a few nucleotides aka DNA methylation. Such changes can then be inherited by the next few generations, and so these folks claim such changes can be subjected to natural selection which leads to a form of evolutionary change similar to the old, bygone Lamarckian theory of inheritance of acquired characters. Apparently, traditional evolutionary theory doesn’t account for this mechanism and hence is in dire need for change!!

But some important aspects which people misread are the following:

  • This form of  neo-Lamarckian inheritance is not permanent and is wiped clean after a few generations. The most touted example of epigenetic changes inheritance in a plant lasted for 31 generations before being erased. And till now, no evidence has come up regarding epigenetic changes being inherited in a vertebrate.
  • When geneticists trace any adaptive changes being found on the genome, what is seen are the actual, real changes in the DNA sequence itself and not on the presence/absence of methyl markers on those nucleotides making up the sequence.
  • The increase in the frequency of DNA sequences which are susceptible to environmentally-induced methylation because them being adaptive is straight-forward natural selection and doesn’t require a revision of evolution.
  • Some methylation changes are indeed coded by the DNA, as in mediating parent-offspring conflict. But this form of evolution is not because of the environment but has happened due to normal natural selection.

Berman in his potpourri article used niche construction as an example of how epigenetics can work . But what he didn’t understand was that niche construction result more from DNA sequence changes which are adaptive to the novel environment the organism encounters and not due to the environment. As Jeffrey Coyne put it brilliantly – “Berman has no idea what he’s talking about here.”

In regards to the much-advertised meeting held by Royal Society – “New Trends in Evolutionary Biology: Biological, Philosophical, and Social Science Perspectives.” many of the attendees were sponsored by the Templeton Foundation which in recent years has led the highly stupid movement of bridging science and religion. It’s been the case that they have funded any project which is woozy and unscientific but sounds sciency/lofty in its aims. Check some of these woozy grants out –

So, this brings a huge doubt as to the impartial scientific motive behind this conference. Are these so-called revisionists simply “careerists” as Jeffrey Coyne puts it? Sadly, in this era of waning grants and increasing pressure to publish in high-impact journals (which itself is a crap idea to measure science) some people have come up with these half sciency, half baloney ideas which promise the moon all the while being blind.

This misunderstanding of epigenetics and the extent of its role is not restricted to these but even respected scientist/Pulitzer-winning author Siddhartha Mukherjee did a similar faux pas this summer with his article in The New Yorker. Nature even wrote an article collating the various viewpoints on the issue. His mistake was not claiming that evolution needs an overhaul but more nuanced, as he said that epigenetic markers play a huge role in gene regulation. What is now known to every biologist is that it’s transcription factors (proteins) which control the rate of transcription from DNA to messenger RNA, by binding to a specific DNA sequence. In turn, this helps to regulate the expression of genes near that sequence. Now, this coming from The New yorker and Mukherjee would convince layman about the role of epigenetic markers in gene regulation despite them not being true !! And the final nail in the coffin was when towards the end of the article he speculated that such inheritance of acquired characters via epigenetic markers (Lamarckism at its best !) could play a major role in evolution. As it’s been said, again and again there is simply no evidence for this and hence needless speculation based on shaky ground is harmful to science.

For more:

  1. The Role of Methylation in Gene Expression
  2. Researcher under fire for New Yorker epigenetics article
  3. The Imprinter of All Maladies
  4. Once again: misguided calls for a thorough revamping of evolutionary biology
  5. The New Yorker screws up big time with science: researchers criticize the Mukherjee piece on epigenetics

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