Are viruses alive? Perhaps we’re asking the wrong question

From the June 8, 2020 article at The Conversation

“The truth is, we don’t fully understand viruses, and we’re still trying to understand life. Some properties of living things are absent from viruses, such as cellular structure, metabolism (the chemical reactions that take place in cells) and homeostasis (keeping a stable internal environment).

This sets viruses apart from life as we currently define it. But there are also properties that viruses share with life. They evolve, for instance, and by infecting a host cell they multiply using the same cellular machinery.”

Read the entire article at https://theconversation.com/are-viruses-alive-perhaps-were-asking-the-wrong-question-139639

Are viruses alive? Perhaps we’re asking the wrong question

This June 8, 2020 article from The Conversation goes into some depth on how we define life alters how we categorize living versus non-living things.

Viruses have some characteristics of living things as DNA, the ability to change animal and plant DNA, and the ability to evolve. However they do not have a cell structure or a stable internal environment.

The complexity of this question is furthered by posing questions of forms that seem to be life outside of earth. What would be the qualifiers? or the select indicators that life is present?

The article concludes life is a human construct. Nature, evolution, and life exist without human categories. So some theorize that viruses are just on an evolutionary continuum regardless if we call them living or not.

[Press release] Did genetic links to modern maladies provide ancient benefits?

From the 28 January 2015 press release at University at Buffalo

study finds that humanity’s early ancestors had genetic variations associated with modern disease, and now the question is why

By Charlotte Hsu

The discovery highlights the importance of balancing selection, a poorly understood evolutionary dance in which dueling forces drive species to retain a diverse set of genetic features.

Credit: From Shaping Humanity, by John Gurche. Image may be republished ONLY in conjunction with stories about the research outlined in this press release.

Caption: A reconstruction ofHomo neanderthalensis, as created by artist John Gurche for the Smithsonian’s National Museum of Natural History. A study led by University at Buffalo biologist Omer Gokcumen compared the DNA of modern humans to Neanderthals and Denisovans (another ancient hominin). The research found that genetic deletions associated with various aspects of human health, including psoriasis and Crohn’s disease, likely originated in a common ancestor of the three species.

BUFFALO, N.Y. — Psoriasis, a chronic skin condition, can cause rashes that itch and sting.

So why would a genetic susceptibility to this and other ailments persist for hundreds of thousands of years, afflicting our ancient ancestors, and us?

That’s the question scientists are asking after discovering that genetic variations associated with some modern maladies are extremely old, predating the evolution of Neanderthals, Denisovans (another ancient hominin) and contemporary humans.

The study was published this month in Molecular Biology and Evolution.

“Our research shows that some genetic features associated with psoriasis, Crohn’s disease and other aspects of human health are ancient,” says senior scientist Omer Gokcumen, PhD, a University at Buffalo assistant professor of biological sciences.

Some of humanity’s early ancestors had the telltale features, called deletions, while others did not, mirroring the variation in modern humans, the scientists found. This genetic diversity may have arisen as far back as a million or more years ago in a common ancestor of humans, Denisovans and Neanderthals.

The discovery highlights the importance of balancing selection, a poorly understood evolutionary dance in which dueling forces drive species to retain a diverse set of genetic features.

The research raises the possibility that the diseases in question — or at least a genetic susceptibility to them — “may have been with us for a long time,” Gokcumen says.

Why this would happen is an open question, but one possibility is that certain traits that made humans susceptible to Crohn’s and psoriasis may also have afforded an evolutionary benefit to our ancient ancesto

– See more at: http://www.buffalo.edu/news/releases/2015/01/034.html#sthash.latn4ejg.dpuf

Microbes can influence evolution of their hosts

From the 18 July 2013 article at EurkAlert

Microbes can influence evolution of their hosts

New evidence supporting the hologenome theory of evolution

		IMAGE: This is an illustration of the tree of life created in microbial culture. Click here for more information.

You are not just yourself. You are also the thousands of microbes that you carry. In fact, they represent an invisible majority that may be more you than you realize.

These microscopic fellow travelers are collectively called the microbiome. Realization that every species of plant and animal is accompanied by a distinctive microbiome is old news. But evidence of the impact that these microbes have on their hosts continues to grow rapidly in areas ranging from brain development to digestion to defense against infection to producing bodily odors.

Now, contrary to current scientific understanding, it also appears that our microbial companions play an important role in evolution. A new study, published online on July 18 by the journal Science, has provided direct evidence that these microbes can contribute to the origin of new species by reducing the viability of hybrids produced between males and females of different species. [my emphasis]

This study provides the strongest evidence to date for the controversial hologenomic theory of evolution, which proposes that the object of Darwin’s natural selection is not just the individual organism as he proposed, but the organism plus its associated microbial community. (The hologenome encompasses the genome of the host and the genomes of its microscopic symbiotes.)

“It was a high-risk proposition. The expectation in the field was that the origin of species is principally driven by genetic changes in the nucleus. Our study demonstrates that both the nuclear genome and the microbiome must be considered in a unified framework of speciation,” said Associate Professor of Biological Sciences Seth Bordenstein who performed the study with post-doctoral fellow Robert Brucker.

They conducted their research using three species of the jewel wasp Nasonia. These tiny, match-head sized wasps parasitize blowflies and other pest flies, which make them useful for biological control.

“The wasps have a microbiome of 96 different groups of microorganisms,” [My emphasis]said Brucker. Two of the species they used (N. giraulti and N. longicornis) only diverged about 400,000 years ago so they are closely related genetically. This closeness is also reflected in their microbiomes, which are quite similar. The third species (N. vitripennis), on the other hand, diverged about a million years ago so there are greater differences in both its genome and microbiome, he explained.

The mortality of hybrid offspring from the two closely related species was relatively low, about 8 percent, while the mortality rate of hybrid offspring between either of them and N. vitripennis was quite high, better than 90 percent, the researchers established.

“The microbiomes of viable hybrids looked extremely similar to those of their parents, but the microbiomes of those that did not survive looked chaotic and totally different,” Brucker reported.

The researchers showed that the incompatibilities that were killing the hybrids had a microbial basis by raising the wasps in a microbe-free environment. They were surprised to find that the germ-free hybrids survived just as well as purebred larvae. But when they gave the germ-free hybrids gut microbes from regular hybrids, their survival rate plummeted.

“Our results move the controversy of hologenomic evolution from an idea to an observed phenomenon,” said Bordenstein. “The question is no longer whether the hologenome exists, but how common it is?”

 

 

Related articles

• Microbes Influence Evolution Of Their Hosts – Research Confirms Hologenomic Evolution (planetsave.com)
• Our Destiny Lies Not In Our Stars, But In Our Bacteria (psmag.com)
• Gut Microbes Can Split a Species (news.sciencemag.org)
• Microbes can influence evolution of their hosts (sciencedaily.com)
• Gut microbes may put barrier between species (sciencenews.org)

 

Human Brains Unlikely To Evolve Into A “supermind” As Price To Pay Would Be Too High

From the 8 December 2011 Medical News Today article

Human minds have hit an evolutionary “sweet spot” and – unlike computers cannot continually get smarter without trade-offs elsewhere, according to research by the University of Warwick.

Researchers asked the question why we are not more intelligent than we are given the adaptive evolutionary process.

Their conclusions show that you can have too much of a good thing when it comes to mental performance.

The evidence suggests that for every gain in cognitive functions, for example better memory, increased attention or improved intelligence, there is a price to pay elsewhere – meaning a highly-evolved “supermind” is the stuff of science fiction….

…

For instance, among individuals with enhanced cognitive abilities such as savants, people with photographic memories, and even genetically segregated populations of individuals with above average IQ, these individuals often suffer from related disorders, such as autism, debilitating synaesthesia and neural disorders linked with enhanced brain growth.

Similarly, drugs like Ritalan only help people with lower attention spans whereas people who don’t have trouble focusing can actually perform worse when they take attention-enhancing drugs.

Dr Hills said: “These kinds of studies suggest there is an upper limit to how much people can or should improve their mental functions like attention, memory or intelligence….

Related articles

• Why our minds have probably evolved as far as they can go [Neuroscience] (thepurplebrain.wordpress.com)
• Why human brains can’t get any smarter (news.bioscholar.com)
• Why aren’t we smarter already? Evolutionary limits on cognition (eurekalert.org)
• Why our minds have probably evolved as far as they can go [Neuroscience] (io9.com)
• Brains Of Taxi Drivers Change As They Learn To Navigate The Streets (medicalnewstoday.com)
• Changes In The Path Of Brain Development Make Human Brains Unique (medicalnewstoday.com)
• Why aren’t we smarter already? (3quarksdaily.com)
• The Evolved Self-Management System (basicrulesoflife.wordpress.com)
• How Music and Language Mimicked Nature to Evolve Us (brainpickings.org)

Are humans still evolving by Darwin’s natural selection?

Are humans still evolving by Darwin’s natural selection?

From the 28 February 2011 BBC article

n 1859, Charles Darwin published On the Origin of Species, a book which transformed our understanding of how life on Earth developed – but ever since then, scientists have wondered whether humans were resourceful enough to remove themselves from the grip of natural selection.

There is no question that humans are unique in the animal world. We have developed technologies that shelter us from the harshness of the environment in a way that no other creatures have managed.

While polar bears evolved thick coats of blubber to insulate them from the Arctic cold, humans could skin that polar bear, and use the pelt as clothing to keep warm.

Does this mean that, at some point, technological advances have stopped us evolving?

Much of the story is in our genes and the sequencing of the human genome has helped unlock the answers.

By comparing the genes of people from all around the world, scientists can see how different we all are, and therefore how much we have evolved apart from each other since our species first appeared.

Skin colour is the most obvious way we have evolved apart, but there are other examples.

“We are living records of our past,” says Dr Pardis Sabeti, a geneticist at Harvard University. “And so we can look at the DNA of individuals from today and get a sense of how they all came to be this way.”

Another area of recent evolution is how our metabolism has changed to allow us to digest some things that we could not in the past.

The most obvious example of this is lactose, the sugar in milk. Some 10,000 years ago, before humans started farming, no one could digest this beyond a few years of age.

But today, the rate of lactose tolerance in different parts of the world is a clue to the different histories of farming across the globe. While 99% of Irish people are lactose tolerant, in South East Asia, where there is very little tradition of dairy farming, the figure is less than 5%.

So clearly our technology and inventions didn’t stop us evolving in the past. But what about today?

Professor Steve Jones, a geneticist at University College London, said: “In Shakespeare’s time, only about one English baby in three made it to be 21.”

“All those deaths were raw material for natural selection, many of those kids died because of the genes they carried. But now, about 99% of all the babies born make it to that age.”

The bulk of medical and other technological developments which protect us from our environment have come in just the past century. So in the developed world today, what is there left for natural selection to act on?

“Natural selection, if it hasn’t stopped, has at least slowed down,” says Jones…..

 

 

 

New research suggests that obesity and diabetes are a downside of human evolution

New research suggests that obesity and diabetes are a downside of human evolution

New research in the FASEB Journal suggests that a gene called CMAH has been lost during the course of recent evolution, and may lead to an increased risk of Type 2 diabetes in humans

From the February 25 2011 Eureka news alert

As if the recent prediction that half of all Americans will have diabetes or pre-diabetes by the year 2020 isn’t alarming enough, a new genetic discovery published online in the FASEB Journal. *** provides a disturbing explanation as to why: we took an evolutionary “wrong turn.” In the research report, scientists show that human evolution leading to the loss of function in a gene called “CMAH” may make humans more prone to obesity and diabetes than other mammals.

“Diabetes is estimated to affect over 25 million individuals in the U.S., and 285 million people worldwide,” said Jane J. Kim, M.D., a researcher involved in the work from the Department of Pediatrics at the University of California, San Diego in La Jolla, CA. “Our study for the first time links human-specific sialic acid changes to insulin and glucose metabolism and therefore opens up a new perspective in understanding the causes of diabetes.”

In this study, which is the first to examine the effect of a human-specific CMAH genetic mutation in obesity-related metabolism and diabetes, Kim and colleagues show that the loss of CMAH’s function contributes to the failure of the insulin-producing pancreatic beta cells in overweight humans, which is known to be a key factor in the development of type 2 diabetes. This gene encodes for an enzyme present in all mammalian species except for humans and adds a single oxygen atom to sialic acids, which are sugars that coat the cell surface.

To make their discovery, the researchers used two groups of mice. The first group had the same mutant CMAH gene found in humans. These mice demonstrated that the CMAH enzyme was inactive and could not produce a sialic acid type called NeuSGc at the cell surface. The second group had a normal CMAH gene. When exposed to a high fat diet, both sets of mice developed insulin resistance as a result of their obesity. Pancreatic beta cell failure, however, occurred only in the CMAH mutant mice that lacked NeuSGc, resulting in a decreased insulin production, which then further impaired blood glucose level control. This discovery may enhance scientific understanding of why humans may be particularly prone to develop type 2 diabetes. Results may also suggest that conventional animal models may not accurately mirror the human situation.

“The diabetes discovery is an important advance in its own right. It tells us a lot about what goes wrong in diabetes, and where to aim with new treatments,” said Gerald Weissmann, M.D., Editor-in-Chief of the FASEB Journal, “but its implications for human evolution are even greater. If this enzyme is unique to humans, it must also have given us a survival advantage over earlier species. Now the challenge is to find the function of CMAH in defending us against microbes or environmental stress or both. This evolutionary science explains how we can win some and lose some, to keep our species ahead of the extinction curve.”

**For suggestions on how to get this article for free or at low cost click here

Related articles and Web sites

Related Articles

• Food Processing and Obesity (education.com)
• How Can an Unhealthy Diet Cause Diabetes? (brighthub.com)
• Diabetes (MedlinePlus) has links to overviews, basic information, health check tools, research findings, reference materials, and more