March 1, 2022 | David F. Coppedge

How to Adapt Without New Genes

Scientists are finding out, to their surprise, that organisms
can adapt without mutations and natural selection

 

Neo-Darwinism may die the death of a thousand cuts. Biologists are finding new ways that organisms adapt and survive without RM+NS (random mutations and natural selection). Creationists and design advocates have long argued that the ‘mechanisms’ of mutation and selection (if the Stuff Happens Law can be graced with the term ‘mechanism’) cannot add new genetic information. Where does new information come from? In a growing number of cases, it was already built in or readily available from nearby libraries. If the information was already there, no RM or NS was required. Here are some recent examples.

Axolotls ‘Genetically Indistinguishable’ From Other Salamanders (University of Kentucky, 22 Feb 2022). The axolotl is a strange pink salamander native to Mexico – strange because of its Peter-Pan trait of pedomorphy: the never-grow-up ability to retain juvenile traits in adulthood. Unlike other salamanders, the axolotl does not undergo metamorphosis to live on land, but continues living in the water all its life with its baby-pink skin and big gills. Geneticists at the University of Kentucky expected to see the axolotl as a distinct species when its genome was sequenced, but they found its genome is ‘genetically indistinguishable’ from other salamanders like the land-dwelling tiger salamander.

We assumed the opportunity for gene flow (in axolotls) was really low — if your body doesn’t allow you to move across land, then that means genes aren’t going to go out and other genes won’t come in,” said David Weisrock, professor and chair of the UK Department of Biology and co-author of the study. “But our data show that is not the case. There’s a strong signature of gene flow moving in and out of axolotl populations that is in contrast to what most biologists would have expected. In fact, it has a very clear evolutionary history of genetic exchange with other salamanders around it.

This implies that axolotls are regular salamanders that have adapted to the particular environment in which they live. Something other than RM+NS is making them take on their pedomorphic form without changing their genes.

If this is not neo-Darwinism, what is it? The UK biologists say it could be a case of “phenotypic plasticity” (a shape-shifting ability where the genome is flexible enough to create several phenotypes from one genotype). Or, it could be due to “local adaptation” which tries to rescue NS without RM: “where an environment (such as a lake) leads to natural selection that maintains a phenotype, or a particular trait, despite there being gene flow from other populations.” How can that be? It sounds like a rescue device. If no genetic change occurs, there will be no speciation, and no progress up Darwin’s mythical tree of life. Whether by phenotypic plasticity or local adaptation, it will be the same species genetically. Here is a case where sequencing a genome did not “shed light on evolution.”

“A study like this presents new opportunities for studying regeneration,” said Kathryn Everson, Ph.D., co-author and former postdoc at UK. “One of the most interesting traits about the axolotl is its paedomorphy, and our study sheds light on just how important that trait is for promoting diversification, or allowing new species to evolve. And it turns out, it’s not as important as we once thought. We know now that all of these salamander species are very closely related to one another. So rather than only focusing on the axolotl — an extremely endangered species — maybe we think about things differently moving forward.”

The scientists are ditching natural selection and turning their attention to the amazing regenerative abilities of the axolotl. You can cut off a limb on this creature and it will grow a new one. They hope that this new focus will shed light on possible inherent abilities for regeneration of damaged parts in humans. Their paper is published in PNAS, where they admit that there’s no evidence for genetic natural selection or speciation in the axolotl compared to other salamanders in the tiger salamander complex.

Everson et al., “Geography is more important than life history in the recent diversification of the tiger salamander complex,” PNAS 118 (17) e2014719118, April 22, 2021, https://doi.org/10.1073/pnas.2014719118.

To save face, they try to suggest that they’ve learned something about evolution, but it’s in futureware:

Lingering questions notwithstanding, this large-scale genetic and geographic study establishes a framework for understanding the evolutionary history of the A. tigrinum species complex.

If they only have the framework, they do not have the understanding of evolutionary history that it was made for.

Wild Wild Life newsletter: When species steal each other’s genes (New Scientist, 17 Feb 2022). “Recent discoveries of horizontal gene transfer reveal that animals and plants are swapping genes across different species,” writes blogger Penny Sarchet, “but how do they do it and what might it mean for evolution?” It might just mean evolution by neo-Darwinian theory is dying. If genes are being stolen, they already had to exist. Where, then, is random mutation and natural selection? The genetic information did not emerge, like Darwin thought, by slight successive modifications. It was already there.

Now, here’s something surprising. Computational analysis suggests that a species of whitefly (Bemisia tabaci, pictured above) has acquired 50 genes from the plants they eat. No discovery like this has ever been made before, and while we don’t know how the genes got into the flies, there are signs that the genes are functional….

The finding suggested that horizontal gene transfer – the movement of useful DNA codes between entirely different species – may be much more widespread in the natural world than we suspected. Now, a different team has analysed the DNA of the whitefly to identify a full 50 genes that appear to have come from plants, and experiments suggest that many of them are used by the fly.

That would have seemed impossible to geneticists a few decades ago. Each species has its own genome. Those do not cross boundaries; they distinguish species. A master of disaster, Sarchet smiles and rescues Darwin from the catastrophic implications of this surprise.

I love anything that turns our understanding of genetics upside down, especially when there are implications for evolution.

What? Is she becoming an advocate for intelligent design? Clearly not, or else New Scientist would cancel her forthwith.

With evolution defenders like Sarchet, Darwin can’t lose. Even falsifying evidence becomes evidence for his theory. Darwin’s web of belief (or web of deceit, if you prefer) remains strong as ever.

 

(Visited 380 times, 1 visits today)

Comments

Leave a Reply