New discovery challenges long-held evolutionary theory

New discovery challenges long-held evolutionary theory
Mike McDonald, a recent ARC Future Fellow with Laura Woods (left) and Aysha Sezmis (right). Credit: Steve Morton

Monash scientists involved in one of the world's longest evolution experiments have debunked an established theory with a study that provides a 'high-resolution' view of the molecular details of adaptation.

Many of the challenges facing the world today are the result of evolutionary processes.

"Cancer is an evolving group of cells within your body, antibiotic resistance is the result of bacteria adapting to the use of antibiotics, and climate change is forcing whole ecosystems to adapt or die," said study co-lead author Dr Mike McDonald, from the Monash School of Biological Sciences.

"A major goal of modern evolutionary biology is to be able to predict or anticipate evolutionary changes," he said.

"Our study, published in Nature, provides a high-resolution view of the molecular details of adaptation over substantial evolutionary timescales.

"The insights we provide into the rate, repeatability, and molecular basis of adaptation will contribute to a better understanding of these and challenges."

Dr McDonald, a recent ARC Future Fellow, specialises in the genetics of adaptation. To explore this area Dr McDonald's lab propagates populations of yeast and other microbes such as E.coli for thousands of generations in a variety of laboratory environments.

Dr McDonald has been involved in the 'E.coli long-term evolution experiment' – an ongoing experimental evolution study now in its 30th year led by Richard Lenksi. This study has been following the genetic changes in 12 initially identical E.coli populations.

"The Lenski study is the longest running microbial evolution experiment with more than 67,000 generations of E.coli, which is equivalent to over one million years of human evolution," Dr McDonald said.

"In our study we found that even though the E. coli populations in our experiment have been evolving in a very simple environment for a long time, they are still adapting to their environment.

"In other words the fit get fitter.

"But the established theory tells us that adaptation should have stopped by now since there should be a 'fitness peak'" that the E.coli should have reached by now – and our work shows that this is not the case."

According to Dr McDonald, one explanation is that as E. coli evolve, they change the environment that they are growing in. This change to the then drives further evolution, so that the populations may never stop adapting.

In his study, researchers undertook genome sequencing which allowed them to track over 33,000 mutations for 61,000 generations of evolution, providing them resolution they needed.

"This also gave us a comprehensive view of how repeatable adaptation is, and how random effects can affect the outcomes of ," Dr McDonald said.


Explore further

Gauging evolutionary adaptation- are our models right?

More information: Benjamin H. Good et al. The dynamics of molecular evolution over 60,000 generations, Nature (2017). DOI: 10.1038/nature24287
Journal information: Nature

Provided by Monash University
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Oct 19, 2017
Even if the environment didn't change, the population becomes its own environment and starts competing within itself, changing the criteria of fitness continuously. Evolution has no end goal in conserving particular genes or maintaining homogeneity within populations.

Oct 19, 2017
Charles Darwin in his 1877 book "The various contrivances by which orchids are fertilised by insects" said essentially the same thing; as organisms evolve they change the environment that they and other species evolve within.

While it is nice to have more accurate molecular biology showing the mechanisms, it is far from a "challenge to long held theory."

Oct 19, 2017
Even if the environment doesn't change, there can be increasingly improbable things in the environment for evolution to stumble upon. The Scientific American Science Talk Podcast discussed Lenksi's experiment at the 22:00 mark in the Sept. 27, 2017 episode "Does Evolution Repeat Itself?" The environment was purposely nutrient poor for the 12 identical starter populations of E. coli, with many materials they don't metabolize. 30,000 generations in (at 6/day), one population stumbled upon the 3+ mutations it took for the E. coli to be able to metabolize citrate in the presence of oxygen. This happened literally in a single day. The lab assistant came in one morning and found that one population had explosive growth due to the new food source. 44,000 generations later, none of the 11 others have made this leap.

https://www.scien...-itself/

Oct 19, 2017
It's silly that there was ever an idea of a fitness peak to begin with. Evolution doesn't necessarily produce the best possible design--it's just good enough to survive to reproduce more often than the next organism. There's always plenty of room to improve on that. Once the population is all "good enough," the process will repeat because now everyone is fighting for the same resources with the same tools. Meanwhile, as noted, these new organisms change the environment by using the resources and being the competition.

Oct 20, 2017
On a more practical note, human evolution has been thwarted by modern civilization. Technological advances and the welfare state militates against the maximization of human physical and mental potential.

Oct 20, 2017
Hopefully these researchers are tracking the environmental changes, including those produced by population growth. It would be sad to miss that data.

Oct 20, 2017
According to Dr McDonald, one explanation is that as E. coli evolve, they change the environment that they are growing in. This change to the environment then drives further evolution, so that the populations may never stop adapting.

Something like this has been seen several time in predator/prey evolutikon over the ages.
Prey evolves tougher hides (up to and including scales or defenses like spikes) - predators grow larger teeth and more muscle mass to cope. At which point predators have so much mass that they slow down which favors prey that has less weight (less scales/tough hides) but is faster. An extreme example was the Sabre tooth tiger which had so massive teeth it could not move very fast.

The evolution of prey shapes their environment (the predators) while the evolution of the predator in turn shapes their environment (the prey)

Takeway message: there is no 'end goal' for evolution. It can be a dynamic equilibrium that goes round and round in cycles.

Oct 20, 2017
Even if the environment didn't change, the population becomes its own environment and starts competing within itself, changing the criteria of fitness continuously. Evolution has no end goal in conserving particular genes or maintaining homogeneity within populations
Ah So you learn a little something about human evolution as well, eh?

But humans found that the best way to compete was in tribes. And when they began living in tribes, natural selection gave way to group selection. Humans began to be selected for the very unnatural behaviors required of tribal living. And evolution itself began to give way to domestication.

The humans who could not surrender their natural proclivities were systematically culled. Tribes became larger, stronger, more cohesive, and more successful in competition with others.

And these tribes would overrun the competition, kill the males, and incorporate the females, thereby accelerating the whole process enormously.

Oct 20, 2017
So by using the world(s) "evolution" and "evolutionary processes" and "adaptation" does the whole article have anything to do with the supposed Darwinian evolution whereby one kind of organism can undergo wholesale changes and become another distinctly recognizable organism?

In the Lensky experiments, have those bugs become anything other than what they started out as, given that they've undergone the "equivalent of million years of human evolution" ?
Or are they still just E.coli? Not red blood cells or maybe bone marrow cells?

What I'm getting to is that the whole underlying message here is that we observe adaptation and imply the unobservable and unobserved Darwinian cross-organism evolution.
In short - equivocation.


Oct 20, 2017
Darwinian evolution whereby one kind of organism can undergo wholesale changes and become another distinctly recognizable organism?

Erm...no. This is not the definition of any kind of evolution (least of all 'Darwinian evolution')...this is some kind of fantasy you fabricated out of thin air. That you rail against your own fantasy is not surprising, as it is as crazy as you are.

Oct 20, 2017
@Anti everything - perhaps you'd like to present your version of Darwinian evolution and also explain how a single cellular organism supposedly became a human being while you're at it?
Instead of engaging in attacking the person why don't you rather reveal your superior intellect and knowledge and explain the explainable?

Oct 20, 2017
explain how a single cellular organism supposedly became a human

It goes something like this:

Cells reproduce with slight variation.
Environment selects the variation(s).
Time elapses.

Of course I'm just a layman, and considering the volume of information on the subject, you should probably just go read some of the info online.

Oct 20, 2017
perhaps you'd like to present your version of Darwinian evolution and also explain how a single cellular organism supposedly became a human being while you're at it?

Well, we do grow from a single cell into a fully formed human being. It is possible to have the full information in a cell.

We have observed speciation in organisms. Of course E. Coli will not spring into fully formed humans over night (and no interpretation of evolution says so). But over billions of years given the right kind of environmental pressures you can get all kinds of interesting changes going.
That we're still made up of cells and that these cells contain some truly archaic components (mitochondria) should give you a clue.
That the basics (DNA/RNA) are the same in the most primitive cells and in humans should give you a clue.
That certain molecules (like sugars) only appear in one chirality and not in the opposite - accross the entirety of all organisms - should give you a clue.

Oct 20, 2017
@Anti everything - perhaps you'd like to present your version of Darwinian evolution and also explain how a single cellular organism supposedly became a human being while you're at it?
Perhaps you could explain how a god who doesn't exist could make this happen? You know, the omniscient, omnipotent, morally impeccable one who nevertheless wrote a book about events we know never happened and people we know never existed?

That's a much bigger stretch dont you think?

Oct 23, 2017
@Ghost
Perhaps you could explain how a god who doesn't exist could make this happen?

Well, perhaps you can explain how the impossible thing of life arising spontaneously from non-living materials can happen all by itself with no intelligent and highly sophisticated tools (which humans don't even have at this moment) from the outside?

Just because you cannot see or detect God physically doesn't mean that He doesn't exist. On the balance of evidence from life and the existence of stars and planets(which cannot form all by themselves - a scientific fact by the way ) it is clear that someone must have created it.

If you insist that everything has created itself(from nothing) you have a major, major problem from a strictly scientific point of view. Then you have to invent things like multiverses ( completely unscientific by the way) and branes to escape the glaring scientific errors.

Oct 23, 2017
@Ghost
events we know never happened and people we know never existed

Perhaps you should investigate just ONE incident on which the bible is accurate to the tee:
Jericho. The bible was the only historical document that even mentioned the EXISTENCE of such a place. Then to top it off, the findings of a broken wall that had fallen down to allow access as well as the burnt wheat which was obviously at spring time harvest and so on, testifies just how accurate the bible is as a document of historical events. Oh, did I mention that the whole city was burnt down with NOTHING apparently stolen?

Perhaps you'd like to dispute the time of the occurrence - as per normal bible deniers - go and watch the video "Patterns of evidence" and judge for yourself.

The bible is not a scientific manual, that is definitely a fact. It is a historical eye-witness account of human origins and truth of our Creator. However, where it touches on scientifically challenging issues, it comes out trumps.

Oct 23, 2017
@Anti-alias
we do grow from a single cell into a fully formed human being. It is possible to have the full information in a cell.


Now, ain't that just dandy! Evolution on a blindingly fast scale - from single cellular organism to fully grown human being in the blink of an evolutionary eye! This is true evolution, I agree.

But now, where did that information come from in the first place? You'll have to explain how it is possible for purely materialistic random physical and chemical processes to create the abstract entity we know as information. That information contains things like size, structure, composition, functionality, integration and repair. Just how did those come from purely materialistic interactions? Can the abstract arise from the purely material interactions?

The information specified in the DNA structure is not dependent on the chemical makeup. We can extract and record it elsewhere digitally-eventually.

Oct 23, 2017
@robodog
It goes something like this:

That's the problem with the evolutionary story - it's precisely just that - a hand-waving story with absolutely zero science to back it up. So far there's absolutely no scientifically accepted way to demonstrate how the supposed Darwinian evolution happened. People keep on chanting the same random mutation and natural selection mantra but cannot show that it really works in real life.
The current paradigm cannot even show how life arrived here in the first place. And both abiogenesis and Darwinian evolution suffer from the same malady: How to get the abstract entity known as information out of purely materialistic processes? HOW?
The information contained in the living cell is vast and highly superior than anything that human beings have EVER invented or discovered and fully explained. So how on earth can this happen all by itself via random processes? Take a working SW program and introduce random errors and see how long it lasts.

Oct 23, 2017
@Antialias
We have observed speciation in organisms.

That is certainly true. However, having observed speciation which springs from already existing information, scientists need to show that their extrapolation of that process is valid and applicable to the actual creation of the whole spectrum of life as it exists on earth.
They are still at it and not getting very far. So far there is no scientifically undisputed and accepted THEORY that demonstrates this. By theory I mean the true scientific meaning of the word - having demonstrated itself to be applicable in just about every case where it has been applied or tested against. So far there hasn't been ANY recorded case of one kind of creature changing into some other kind over even the longest period of human time, with full understanding of what it means regarding speciation.

Oct 23, 2017
@antiAlias
Of course E. Coli will not spring into fully formed humans over night (and no interpretation of evolution says so). But over billions of years given the right kind of environmental pressures you can get all kinds of interesting changes going.

You make this statement as if it's a fact but this is precisely where the whole dispute arises: No one can back up your statement of changes over billions of years. There's no observational evidence and no record of the exact process whereby purely materialistic processes gives rise to vast amounts of new highly functional and integrated systematic information. People can point to dead bodies captured in stone and jump to conclusions to suite their own belief system but cannot present a coherent, step by step explanation that shows how one kind of thing morphed into some other over that vast time range.
Your statement unfortunately comes across as just so mush bluster and hand-waving at this point in time.

Oct 23, 2017
@antialias
That the basics (DNA/RNA) are the same in the most primitive cells and in humans should give you a clue.
That certain molecules (like sugars) only appear in one chirality and not in the opposite - accross the entirety of all organisms - should give you a clue.

Strange that you should mention these things - they are precisely those things that stand firmly opposed to abiogenesis and evolution! Yet here you are using them as if they are the epitome of evolutionary proof!!!
The fact that amino acids and sugar are chiral (left and right, respectively) means that either some great miracle of chemistry and physics occurred in the distant past or else someone intelligent and with vastly superior tools, techniques and ability orchestrated precisely that arrangement. We know from current knowledge of chemistry that such a chiral arrangement just does not happen in normal natural chemistry. Huge amounts of effort, energy and skillful technique is required from outside.

Oct 23, 2017
Strange that you should mention these things - they are precisely those things that stand firmly opposed to abiogenesis and evolution!

They have nothing to do with abiogenesis. Note that evolution also has nothing to do with abiogenesis.
Abiogenesis is a totally different theory.

The fact that amino acids and sugar are chiral (left and right, respectively) means that either some great miracle of chemistry and physics occurred in the distant past or else someone intelligent and with vastly superior tools, techniques and ability orchestrated precisely that arrangement

Erm. no. It just means that the first organism used one chirality by chance and that that predilection got copied down. If it were design it would actually be extremely *bad* design, as it leaves half of the possible spectrum of uses on the cutting room floor. Any 'god' that designed this would be a total moron.

Oct 23, 2017
Perhaps you should investigate just ONE incident on which the bible is accurate to the tee:
Jericho
Are you saying that no one knew about that city back then?

Jericho was an abandoned ruin for a few centuries before Joshua would have gotten there.

"...the age of the strata as 1562 BC, with a margin of error of 38 years. These results therefore confirm Kenyon's estimate and cast doubt on the biblical story."

Certainly it was another one of those things that Hebrews would have made up their own legends about.

" See that dead city over there? That's right, our god did that. Aren't you impressed?"

Oct 23, 2017
watch 'patterns of evidence
What, This?

"those conclusions are widely connected to a historical theory which has been carefully negated in scholarship (even among otherwise orthodox biblical scholars). Because of this, I fear that the film's popularity with churches will wind up leaving the church ridiculed for trying to fire another broken arrow at the "white tower establishment"."

-Written by David rohl, former rock musician...

"contrary to what the filmmakers would have you believe, there is nothing new here, just a dejected theory. Indeed, most of the scholars interviewed in the film, even those who believe in a traditional biblical dating of the exodus, reject this revised chronology and opt for less-sensational, less provocative, less game changing, more accurate and more nuanced descriptions of the archaeological evidence of the exodus"

- another jackass in an Indiana Jones outfit.
https://mobile.tw...hl/photo

Oct 23, 2017
The bible is not a scientific manual, that is definitely a fact. It is a historical eye-witness account of human origins and truth of our Creator
Eye witness accounts of human origins... no need to unpack that one... And I thought if you looked directly at god you fried?

Oct 23, 2017
it is clear that someone must have created it
And even if that were true (it's not) it couldn't have been created by the god who claims to be perfect and yet wrote a book full of confirmed LIES.

Perfect gods can't make mistakes Fred.

And no, there are no eyewitness accounts of anything in the bible. The gospels were written long after the apostles died. Upwards of 40% of the Pauline epistles are forgeries. The law of Moses had many different authors, none of whom were Moses. And both the last 11 verses of mark and the 'cast the first stone' parable were added centuries after the original books.

Nothing there reliable at all.

If he had only said 'well you know I try to be perfect but I do make mistakes sometimes but you get the message right?' then perhaps I could believe him [yeah right]. But perfect gods should know that rabbits don't have cuds, camels don't have hooves, and the world is not flat.

Oct 23, 2017
@Anti-alias
we do grow from a single cell into a fully formed human being. It is possible to have the full information in a cell.


Now, ain't that just dandy! Evolution on a blindingly fast scale - from single cellular organism to fully grown human being in the blink of an evolutionary eye! This is true evolution, I agree.

He was referring to how WE start - a a single cell.

But now, where did that information come from in the first place? ... Can the abstract arise from the purely material interactions?

You need to realize info isn't stored only linearly. It's also stored in layers and in the cross chem. interactions, as well.
The information specified in the DNA structure is not dependent on the chemical makeup. We can extract and record it elsewhere digitally-eventually.

It absolutely IS dependent on chemistry...
How do you think they xtract it? Hint -it ain't a tiny tweezers...

Oct 23, 2017
Errata - when i said "-Written by David rohl, former rock musician...", i meant freds film, not my excerpt, which was written by a critic.

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