One-of-a-kind? Or not. USU evolutionary biologist studies formation of new species

February 17, 2017 by Mary-Ann Muffoletto
A plant-eating stick insect of the Timema genus blends with its surroundings to hide from hungry predators. The stout bug was used as a research model by Utah State University evolutionary biologist Zach Gompert and colleagues to explore how new species form. The researchers report insights on the multi-faceted evolutionary process in a Feb. 17, 2017 paper in Nature Ecology & Evolution. Credit: Moritz Muschick

At what point on the journey along the branches of the evolutionary tree does a population become its own, unique species? And is a species still distinct, if it mates with a different, but closely related species? Evolutionary biologist Zach Gompert of Utah State University explores these questions and more, using plant-eating stick insects of the Timema genus as a research model.

With colleagues from ten universities in North America and Europe, Gompert published ecological and genomic insights into stick insect speciation in the Feb. 17, 2017, issue of Nature Ecology & Evolution. His research is supported by the National Science Foundation and the Division of Research Computing in USU's Office of Research and Graduate Studies.

Timema, commonly known as "walking sticks," are cryptic, meaning they visually blend into their surroundings to hide from hungry predators.

"Our work on these insects suggests speciation can be initiated by a few genetic changes associated with natural selection on cryptic color-patterns," says Gompert, assistant professor in USU's Department of Biology and the USU Ecology Center. "While speciation is much more complicated than these changes, Timema's color-patterns provide a window for studying the early phases of the formation of a species."

For the study, the researchers combined field experiments with genomics. They sequenced more than 1,000 stick insect genomes – the genetic material of each organism. Gompert says the size of their study is a research scale rare outside of human population genetic studies.

"Having sequenced the genomes of a thousand individuals, we were able to pick up signals and variations that might have been missed in a smaller sample," he says.

Utah State University evolutionary biologist Zach Gompert is among a team of North American and European researchers, which published ecological and genomic insights into stick insect speciation in the Feb. 17, 2017, issue of Nature Ecology & Evolution. Credit: Mary-Ann Muffoletto, Utah State University

The overall process of generating a new species involves mate choice and the accumulation of genetic differences across the genome in geographically isolated populations, Gompert says. Rapid reversals of speciation can occur when , long separated, once again cross paths and mate.

"When you look at places where two populations co-occur, they are either quite distinct across the entire genome or only distinct in a few regions of the genome," he says. "This could be viewed as an evolutionary gap. However, when you look across space, where populations don't co-occur, you can span this gap because intermediate stages of genetic differentiation are observable."

So, what makes a species its own ?

"We still have a lot of unanswered questions," he says. "While color variations in organisms, such as stick insects, can be striking and inform us of phases of evolution, they're one small aspect of a multi-faceted speciation process."

Additional authors on the paper are Rüdiger Riesch of the University of London; Moritz Muschick, University of Bern; Dorothea Lindtke, Romain Villoutreix, Kay Lucek, Elizabeth Hellen, Victor Soria-Carrasco, Clarissa de Carvalho and Patrick Nosil of the University of Sheffield; Aaron Comeault, University of North Carolina, Chapel Hill; Timothy Farkas, University of Connecticut; Stuart Dennis, Eawag Swiss Federal Institute of Aquatic Science and Technology; Rebecca Safran, University of Colorado; Cristina Sandoval, University of California, Santa Barbara; Jeff Feder, Notre Dame University; and Regine Gries, Bernard Crespi and Gerhard Gries of Canada's Simon Fraser University.

Explore further: Sticking around: Scientists explore parallel evolution in stick insects

More information: Riesch, Rüdiger, et. Al. "Transitions between phases of genomic differentiation during stick-insect speciation," Nature Ecology & Evolution, 17 Feb 2017. DOI: 10.1038/s41559-017-0082

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14 comments

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Bart_A
1 / 5 (5) Feb 18, 2017
Evolution as I think most people understand it, has to include the supposed process of the making of new species with the spontaneous introduction of new genes that did not exist before. Without this you have no evolution as is taught in some textbooks.

Unfortunately for those who believe in evolution, the changes in the organisms described in this article, and any other, does not show this. It is key part of evolution that has never been observed.
cgsperling
4.3 / 5 (6) Feb 18, 2017
Bart: It is amazing, in this age of information, how easy it is to research something before displaying one's ignorance. Search on "new genes observed" and the very first hit.....

https://www.scien...entists/
Whydening Gyre
3.7 / 5 (3) Feb 18, 2017
Evolution as I think most people understand it, has to include the supposed process of the making of new species with the spontaneous introduction of new genes that did not exist before. Without this you have no evolution as is taught in some textbooks.

Unfortunately for those who believe in evolution, the changes in the organisms described in this article, and any other, does not show this. It is key part of evolution that has never been observed.

Here's where you have it wrong. Gene changes aren't "spontaneous". They develop over a period of iterations. Doesn't have to be a huge amount of iterations. RNA is some pretty amazing stuff, which works with a variety of other RNA types and different proteins to eventually change (even RNA, itself) the DNA blueprint (in the GENES). And it's a wickedly relentless, ON-GOING process,
THAT is Evolution - a way more complex process than we can imagine or be simply explained...
Whydening Gyre
3 / 5 (2) Feb 18, 2017
You'll even get relatively similar phenotypes in differing locations if the environment is generally the same...
Or even radically different ones with large environmental contrasts...
(if they survive...)
It's causality based.
"One thing leads to another..."
(An 80s song by the Fixx)
Bart_A
1 / 5 (2) Feb 19, 2017
Search on "new genes observed" and the very first hit.....
https://www.scien...entists/


I studied this article in earnest. Unfortunately your eureka moment doesn't seem to have arrived. The article is dealing with genes that have been turned off or reduced in function. Not adding anything new. Note the gene reported on already had the function of making tryptophan.

Others have also seen such reduction in gene complexity. But not the other way around.

cgsperling
5 / 5 (3) Feb 24, 2017
"Emergence of a new gene from an intergenic region."
https://www.ncbi....19733073

"Recent de novo origin of human protein-coding genes."
https://www.ncbi....19726446

"A Human-Specific De Novo Protein-Coding Gene Associated with Human Brain Functions"
http://journals.p....1000734

Da Schneib
5 / 5 (2) Feb 25, 2017
Bart, it's called recombination and it happens in mammals every time a sperm or an egg is formed. What happens is, the two chromosomes in a homologous pair twist about each other, and randomly get cut apart and then recombined; sometimes, to form new genetic sequences. The split in a gene can occur at any site along the DNA, and occurs at the homologous site on both strands, thus guaranteeing that you'll get, say, 1/3 of one chromosome and 2/3 of the other, for example, when they're recombined.

Anybody with a microscope can see this happen.

That's where new genes come from.

Now stop making up fairy tales about a super magic sky daddy and grow up.
Da Schneib
5 / 5 (2) Feb 25, 2017
Oh, and Bart, to make it even more interesting, mammals, birds, fish, and reptiles all use different versions of this same process, and when you get to plants and protozoa and bacteria and archaea, wildly different. But they all do the same underlying recombination thing, in order to create novel genes. Life on Earth has been doing this for a billion years. That's where all the species came from.

So what I'd suggest you do is go learn some molecular biology before you make any more of a fool of yourself.
Da Schneib
5 / 5 (2) Feb 25, 2017
Now, let's go in the other direction.

Ever heard of a "liger?"

It's the living offspring of a mating between a lion and a tiger.

I'm looking at lions and tigers and I'm making the call these are separate species.

So how can they mate and make a living offspring?

So, now, define "species."

Good luck, Bart.
Da Schneib
5 / 5 (2) Feb 25, 2017
And here's another nasty little conundrum for you, Bart.

Consider ring species. This is a set of species that have developed around a mountain. Species that are close to one another on the mountain can, and do, interbreed, but as they work their way around the mountain, each end of the ring species gets more and more different, until when they meet on the far side of the mountain from where they started, they can't interbreed any more.

Numerous examples exist and have been fully described.

Once again, Bart, define "species."

And once again, good luck with that, Bart.
Da Schneib
5 / 5 (2) Feb 25, 2017
So now, Bart, you have two choices:

1. Go back to your Babble about the super magic daddy in the sky who gives you pie in the sky when you die, written by the drunken Stone Age sheep herders, and reduced to meaninglessness by multiple translations from one language to another, or

2. Find out what's actually going on in the real world.

And honestly, man, good luck with that too. Seriously.
humy
5 / 5 (2) Feb 25, 2017
Evolution as I think most people understand it, has to include the supposed process of the making of new species with the spontaneous introduction of new genes that did not exist before.

Bart_A

Haven't you ever heard of the word "mutation"?
Look it up and then come back to us.
This is how new genes come to exist, no problem.
Mutations are a scientific fact with many scientifically studied and documented cases (just in case you deny mutations can happen)
Da Schneib
5 / 5 (1) Feb 25, 2017
BTW, every human baby born has about 64 mutations. Reference: https://www.ncbi....0386.pdf Page 8 of the PDF, marked page 1674 in the journal of record. About 2/3 of these come from the father (sperm) and 1/3 from the mother (egg). The error bars are an order of magnitude, so between 10 and 100 mutations per generation, more or less. That is for humans only.

Mutation rates vary mostly by the class of organism; some important reasons for this include the exact method of recombination during procreation, how much error checking the genome is subjected to and how accurate that error checking is, and the species' home environments.

They also vary by site; much of large eukaryotes' DNA is non-coding, that is, it is never expressed in the organism, and mutations in these areas therefore do not carry the risk of a nonviable fetus, but mutations in coding DNA are selected against by death before procreation.
[contd]
Da Schneib
5 / 5 (1) Feb 25, 2017
[contd]
Furthermore, this is only the germ-line; within your body, mutations in individual cells also occur, and are fairly common. These do not influence the mutations in any children you might have. You probably have millions of cells in your body that have mutations in them. The overwhelming majority of these are in non-coding DNA for the cell type; of the rest, the majority are fatal and interfere with the working of the cell, and die out and are eliminated. A very few result in cancer of various types, depending on the body cell type, and many of these are detected by your immune system and destroyed. A very, very few actually can grow to be real cancers, and kill you if untreated.

So basically, everyone you know is a mutant. Given this, any argument against evolution because mutations aren't common enough is silliness.

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