Wings of the painted lady butterfly, Vanessa cardui, modified by deletion of non-coding DNA sequence.
Credit: Anyi Mazo-Vargas
This may come as a shock to devoted followers of the Creationist cult, but not to those leading Creationist frauds who specialise in misleading their credulous followers and understand full well that what they claim is designed to mislead and misinform, but scientists working at Cornell University have discovered that non-coding DNA modified from former 'junk' DNA, has a regulatory influence on how the genes which control the markings and colours on some butterflies wings express.
Creations have been conditioned to believe that there is no such thing as junk DNA since it all codes for something and that any change in function must involve an increase in the amount of genetic information (because a loss of information is always deleterious). Junk DNA is of course an embarrassment for Creationists as it belies the notion of intelligent design, and |Creationist dogma now says any mutation is detrimental because it moves the organism further away from the assumed initial perfection of magic creation, the ‘sin’ of ‘The Fall’ having caused ‘genetic entropy’.
Anyone working in the field of genetics will know both these beliefs are nonsense and not supported by the evidence because there are countless examples of advantageous mutations involving a simple substitution in a DNA codon where the number of codons remains the same, yet the meaning of the information changes. There are also countless examples of junk DNA which can be removed without loss of function, because even if the DNA in question is transcribed into messenger RNA (mRNA), it does not result in an active protein being produced.
In the case of butterfly wing patterns, however, the controlling DNA doesn't even code mRNA. The researchers found that it acts like switches that can turn on or off a basic ground plan of markings, turning up some patterns and down others. In this way, evolutionary change can be rapid with small changes to this non-coding, regulatory DNA.
As the Cornell Chronical explains:
Butterfly wing patterns have a basic plan to them, which is manipulated by non-coding regulatory DNA to create the diversity of wings seen in different species, according to new research.The team's findings are published in Science:
The study, “Deep cis-regulatory homology of the butterfly wing pattern ground plan,” published as the cover story in the Oct. 21 issue of Science, explains how DNA that sits between genes – called ‘junk’ DNA or non-coding regulatory DNA – accommodates a basic plan conserved over tens to hundreds of millions of years while at the same time allowing wing patterns to evolve extremely quickly.. The research supports the idea that an ancient color pattern ground plan is already encoded in the genome and that non-coding regulatory DNA works like switches to turn up some patterns and turn down others.Gulf fritillary butterfly, Agraulis vanillaeCredit: Anyi Mazo-Vargas
Previous work in [Professor T.] Reed’s lab has uncovered key color pattern genes: one (WntA) that controls stripes and another (Optix) that controls color and iridescence in butterfly wings. When the researchers disabled the Optix gene, the wings appeared black, and when the WntA gene was deleted, stripe patterns disappeared.We are interested to know how the same gene can build these very different looking butterflies. We see that there’s a very conserved group of switches [non-coding DNA] that are working in different positions and are activated and driving the gene.
Dr Anyi Mazo-Vargas, Ph.D., first author
Department of Ecology and Evolutionary Biology
Cornell University, Ithaca, NY, Now at Department of Biological Sciences, George Washington University
Washington, DC, USA.
This study focused on the effect of non-coding DNA on the WntA gene. Specifically, the researchers ran experiments on 46 of these non-coding elements in five species of nymphalid butterflies, which is the largest family of butterflies.
In order for these non-coding regulatory elements to control genes, tightly wound coils of DNA become unspooled, a sign that a regulatory element is interacting with a gene to activate it, or in some cases, turn it off.
In the study, the researchers used a technology called ATAC-seq to identify regions in the genome where this unraveling is occurring. Mazo-Vargas compared ATAC-seq profiles from the wings of five butterfly species, in order to identify genetic regions involved in wing pattern development. They were surprised to find that a large number of regulatory regions were shared across very different butterfly species.
Mazo-Vargas and colleagues then employed CRISPR-Cas gene editing technology to disable 46 regulatory elements one at a time, in order to see the effects on wing patterns when each of these non-coding DNA sequences were broken. When deleted, each non-coding element changed an aspect of the wing patterns of the butterflies.We have progressively come to understand that most evolution occurs because of mutations in these non-coding regions. What I hope is that this paper will be a case study that shows how people can use this combination of ATAC-seq and CRISPR to begin to interrogate these interesting regions in their own study systems, whether they work on birds or flies or worms.
Professor Robert T, Reed, senior author
Professor of ecology and evolutionary biology
College of Agriculture and Life Sciences
Cornell University, Ithaca, NY, USA.
The researchers found that across four of the species – Junonia coenia (buckeye), Vanessa cardui (painted lady), Heliconius himera and Agraulis vanillae (gulf fritillary) – each of these non-coding elements had similar functions with respect to the WntA gene, proving they were ancient and conserved, likely originating in a distant common ancestor.
They also found that D. plexippus (monarch) used different regulatory elements from the other four species to control its WntA gene, perhaps because it lost some of its genetic information over its history and had to reinvent its own regulatory system to develop its unique color patterns.
AbstractWhat we have here then is a refutation of yet more Creationist dogma and another example of the evolution of evolvability. Not only is there junk DNA but that DNA can be co-opted for novel functions without loss of some previous function which would have been the case had it had a function that Creationist dogma says it should have, but we have an example of where mutations can act as switches which can be selected for or against by the environment, given a mechanism for rapid adaptation by subtle variations in wing colour and patterns.
Butterfly wing patterns derive from a deeply conserved developmental ground plan yet are diverse and evolve rapidly. It is poorly understood how gene regulatory architectures can accommodate both deep homology and adaptive change. To address this, we characterized the cis-regulatory evolution of the color pattern gene WntA in nymphalid butterflies. Comparative assay for transposase-accessible chromatin using sequencing (ATAC-seq) and in vivo deletions spanning 46 cis-regulatory elements across five species revealed deep homology of ground plan–determining sequences, except in monarch butterflies. Furthermore, noncoding deletions displayed both positive and negative regulatory effects that were often broad in nature. Our results provide little support for models predicting rapid enhancer turnover and suggest that deeply ancestral, multifunctional noncoding elements can underlie rapidly evolving trait systems.
Mazo-Vargas, Anyi; Langmüller, Anna M.; Wilder, Alexis; van der Burg, Karin R. L.; Lewis, James J.; Messer, Philipp W.; Zhang, Linlin; Martin, Arnaud; Reed, Robert D.
Deep cis-regulatory homology of the butterfly wing pattern ground plan
Science; 378(6617), 304-308. DOI: 10.1126/science.abi9407
Copyright © 2022 The Authors
Published by American Association for the Advancement of Science
Reprinted with kind permission under license #5415071208270
And of course, as in almost every science paper concerning biology, the TOE, far from being a 'theory in crisis' as Creationist frauds tell their dupes, is shown to be the basis for understanding just about all of biology. Simplistic Creationist superstitions are, by contrast, untestable and unfalsifiable, and completely unsupported by evidence so are incapable of explaining biology in any meaningful scientific way. The mystery is why a Bronze Age superstition is still followed by otherwise normal people in the face of so much evidence against it.
No comments:
Post a Comment
Obscene, threatening or obnoxious messages, preaching, abuse and spam will be removed, as will anything by known Internet trolls and stalkers, by known sock-puppet accounts and anything not connected with the post,
A claim made without evidence can be dismissed without evidence. Remember: your opinion is not an established fact unless corroborated.