Thanks Moonman62.
Posted on 07/14/2018 8:14:11 AM PDT by Moonman62
Humans and mice share approximately 98% of genes, and have similar physiology and anatomy. This is because we share a relatively recent common ancestor, around 80 million-years-ago. In contrast, the ancestor of all animals lived over 500 million-years-ago. As genomic data becomes available for more animal species a detailed family tree can be created, allowing novel insight into the genomes of long extinct species. In the guest post below Jordi Paps summarises recent research that attempts to reconstruct the genome of the ‘first animal’ by using the genomic data available on living animals.
The first animals emerged on Earth at least 541m years ago, according to the fossil record. What they looked like is the subject of an ongoing debate, but they’re traditionally thought to have been similar to sponges.
Like today’s animals, they were made up of many, many different cells doing different jobs, programmed by thousands of different genes. But where did all these genes come from? Was the emergence of animals a small step in evolution, or did it represent a big leap in the DNA that carries the instructions for life?
To answer these questions and more, my colleague and I have reconstructed the set of genetic instructions (a minimal genome) present in the last common ancestor of all animals. By comparing this ancestral animal genome to those of other ancient lifeforms, we’ve shown that the emergence of animals involved a lot of very novel changes in DNA. What’s more, some of these changes were so essential to the biology of animals that they are still found in most modern animals after more than 500m years of independent evolution. In fact, most of our own genes are descended from this “first animal”.
Previous research on lifeforms that are closely related to animals – single-celled organisms such as choanoflagellates, filastereans and ichthyosporeans – has shown they share many genes with their animal cousins. This means that these genes are older than animals themselves and date back to some common ancestor of all these creatures. So the recycling of old genes into new functions, a kind of genome tinkering, must have been an important force in the origin of animals.
But Professor Peter Holland and I wanted to find out which new genes emerged when animals evolved. We used sophisticated computer programs to compare 1.5m proteins (the molecules that genes contain the instructions for) across 62 living genomes, making a total of 2.25 trillion comparisons to find out which genes are shared between different organisms today.
We then created a computer program that could combine this information with the evolutionary relationships of the animals to reconstruct which genes were present in the last common ancestor of all animals. The results don’t represent the ancestor’s full genome, as many genes and other genetic information will no longer exist in today’s animals. But using evolutionary trees to infer what happened in the past in this way is one of the most powerful applications of evolutionary biology, as close as we can come to travelling back in time.
Our results suggest the genomes of the first animals were surprisingly similar to those of modern ones, containing the same proportions of biological functions. Around 55% of modern human genes descend from genes found in the last common ancestor of all animals, meaning the other 45% evolved later.
By applying the same techniques to the genomes of modern relatives of animals, we also reconstructed the genome of even older ancestral organisms. We found that the first animal genome was in many ways very similar to the genomes of these unicellular ancestors.
But then we looked at the novel genes in the first animal genome that weren’t found in older lifeforms. We discovered the first animal had an exceptional number of novel genes, four times more than other ancestors. This means the evolution of animals was driven by a burst of new genes not seen in the evolution of their unicellular ancestors.
Finally, we looked at those novel genes from the first animal that are still found in most of the modern animals we studied. Natural selection should mean that animals keep genes with essential biological functions as the species evolve. We found 25 groups of such genes that had been kept in this way, five times more genes than in other, older, ancestors. Most of them have never been associated with the origin of animals before.
These novel genes that are still widely found today control essential functions that are specifically related to lifeforms with multiple cells. Three groups of these genes are involved in transmitting different nervous system signals. But our analyses show that these genes are also found in animals that do not have a nervous system, such as sponges. That means the genetic basis of the nervous system may have evolved before the nervous system itself did.
Our research shows that both new genes and the recycling of old genes were important in the evolution of animals. But these results raise even more questions. Were novel genes also important in the rise of other types of large multicellular lifeforms such as plants or fungi? What was behind the explosion of novel genes that drove the evolution of animals? Did it happen faster than in other groups or did animal ancestors take a long time to accumulate all the new genes? Answering those questions will require more and better genome data (or improved time-travelling capabilities).
Your statement tells more about you than the study.
It does not “prove” evolution, since nothing is ever proven in science. It does, however, provide strong evidence in support of the evolutionary model.
A salient feature of evolutionary theory is the concept of change over time. That is what the study in this article has shown, in great detail. Furthermore, the nature of the change is exactly what we would expect to see in a system where evolution is the fundamental driver of diversity of the biome.
A creation event implies static genomes. It also implies that any organism should be equally different from any other organism in its class. There are any number of inferences one could make on the assumption that life exists because of a singular creation event in which all existing organisms came into being. But observation tells us that none of those inferences is actually accurate.
Is there an ultimate creator who created a universe in which life could arise, evolve, and exist? That is not a question that is easily answered by scientific inquiry. Personally, I think that the existence of physical laws that allow for life to exist is worthy of a great deal of wonder and awe.
>>Your statement tells more about you than the study.
As does your ad hominem attack.
Read the article. There is nothing observational in there. There is nothing experimental in there. It is pure statistical analysis of a population that has largely never been seen or proven to exist.
Certainly a complex planet full of life, created by itself, would be worthy of wonder and awe. I reserve my wonder and awe for a Creator, one that is not bound by your rules and limits.
The body would not evolve something for which it had no use.
That observation just means it had a use for the genomes prior to being put to that use. We see the same thing occurring today in species which use the same or very similar proteins for differing uses - in some cases for differing uses in different tissues within the same organism.
Goes back to nomenclatures once in use. Over the last few years they’ve been reclassifying and renaming things as they get more specificity around the inner workings.
For example, the idea of “domain” is from the 90s
Time is just a perception.
There is nothing observational in there.
...
There is the observation of decoded genomes.
I did not want to say so before, but I consider the concept of a singular creation event in which everything that now exists sprang into being as extremely constraining, limiting, and unimaginative.
For example, making a ball is trivial. Formulating the physical laws so that properties of hydrophobicity, electromagnetism, charge, intermolecular cohesion, etc., work together in such a way that a sphere can spontaneously form if the physical materials are present is far more of a challenge.
>>There is the observation of decoded genomes.
Observation of theoretical knowledge that is assumed to be true is not observational science.
What it is though, is the circular logic where one theory is presented as fact to prove another and then the second is used as proof for the first. This is “Settled Science” or “Consensus Science”. See Climate Change for more on that form of dishonesty.
Thanks Moonman62.
-—Something like that should be easy to replicate in a lab-—
To achieve enlightenment, you should spend some time in the lab
The lab can be a near by park or especially a state park of some size.
Don’t worry about the fauna. A study of some aspect of the flora will be much more enlightening and will induce further study both at home and in your new lab.
I would suggest buying a Petersons Guide to Wild Flowers as a place to start. Take the field guide, a notebook and perhaps a camera, an open mind and you are in the science business
You will actually observe natural selection
Your opinion is more about epistemology than science. Why is it more credible than a published scientific paper?
You’re welcome. Thanks for the pings.
>>You will actually observe natural selection
Yes I will. Natural selection is micro-evolution, not macro-evolution. The Galapagos Finch had a different beak than a regular finch. It did not have scales or vestiges of a shell. People often confuse natural selection for evolution because that’s what the humanist agenda in schools teaches.
>>Your opinion is more about epistemology than science. Why is it more credible than a published scientific paper?
I never claimed that it was more credible. I am questioning its methodology and finding. In your mind, is “science” a thing that can never be questioned except by people who agree with the findings?
This is why “climate change” is settled science!
Sounds like you got the false Creo teaching down pat. Now get the to your lab for enlightenent.
First animal?? Oh I thought it was Michele Obama they were researching on...Sorry if I offended any FReepers...
What about Humans and Liberals? What is the percentage of liberal genes to Humans (aka Trump Supporters)?
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