Brain Cells We Thought Were Just Fillers Might Actually Be the Key to Our Body Clocks


Neurons aren’t everything.

Scientists have discovered that brain cells that were once considered to be simple place-holders for neurons could actually play an important role in helping to regulate our circadian behaviour.

Astrocytes are a kind of glial cell – the support cells that are often called the glue of the nervous system, as they provide structure and protection for neurons. But a new study shows that astrocytes aren’t just gap-fillers, and may be crucial for keeping time in our inner body clock.

 Scientific consensus has long regarded our internal clock as being controlled by the suprachiasmatic nuclei (SCN), a brain region in the hypothalamus made up of around 20,000 neurons. But there’s about 6,000 star-shaped astrocyte cells in the same area, the exact function of which has never been fully explained.

Now, a team from Washington University in St. Louis has figured out how to independently control astrocytes in mice – and by altering the astrocytes, the scientists were able to slow down the animals’ sense of time.

“We had no idea they would be that influential,” says one of the researchers, Matt Tso.

It was once thought the suprachiasmatic nuclei was the only part of the brain that regulated circadian rhythms, but scientists now understand that cells throughout the body all have their own circadian clocks – including the cells that make up our lungs, heart, liver, and everything else.

In 2005, one of the team, neuroscientist Erik Herzog, helped figure out that astrocytes also include these clock genes.

By isolating the brain cells from rats and coupling them with a bioluminescent protein, Herzog’s team showed that they glowed rhythmically – evidence that they were capable of keeping time like other cells.

 It took more than a decade for the researchers to figure out how to measure the same astrocyte behaviour in a living specimen, by using CRISPR-Cas9 gene-editing to delete a clock gene called Bmal1 in the astrocytes of mice.

Left to their own devices, mice have circadian clocks that last for approximately 23.7 hours. We know this because mice in constant darkness will start running on a wheel every 23.7 hours, and usually don’t miss their time slot by more than 10 minutes.

Humans also miss the 24-hour mark slightly – a Harvard University study in 1999 found that our internal clocks run a tad overlong, on a daily cycle of 24 hours, 11 minutes.

But even though Herzog had demonstrated in 2005 that astrocytes were involved in keeping time, the team didn’t necessarily expect mice without Bmal1 to be affected, because most research surrounding the suprachiasmatic nuclei has demonstrated the controlling effect of neurons, not astrocytes.

“When we deleted the gene in the astrocytes, we had good reason to predict the rhythm would remain unchanged,” says Tso.

“When people deleted this clock gene in neurons, the animals completely lost rhythm, which suggests that the neurons are necessary to sustain a daily rhythm.”

But, to the researchers’ surprise, deleting the clock gene in the astrocytes saw the mouse internal clocks run slower – beginning their daily run about 1 hour later than usual.

In another experiment, the team studied mice with a mutation that caused their circadian clocks to run fast. By repairing this gene in the animals’ astrocytes – but not fixing the defect in their neurons – they weren’t sure what the affect would be.

“We expected the SCN to follow the neurons’ pace,” says Tso. “There are 10 times more neurons in the SCN than astrocytes. Why would the behaviour follow the astrocytes?”

With the mutation fixed in the animals’ astrocytes, the mouse began their running routine 2 hours later than mice that hadn’t had the mutation repaired (in either astrocytes or neurons).

“[These results] suggests that the astrocytes are somehow talking to the neurons to dictate rhythms in the brain, and in behaviour,” Herzog told Diana Kwon at The Scientist.

While the researchers acknowledge that they don’t fully understand the extent to which astrocytes control circadian behaviour, it’s clear something powerful is going on.

Of course, we can’t guarantee yet whether astrocytes in humans are regulating body clocks in the same way, but that’s something that later studies may be able to confirm.

We’ll have to wait to see the results of future research to know more, but until then, one thing’s for sure – these brain cells are definitely there for a lot more than just neuron padding.

Source:http://www.sciencealert.com

The World’s Rarest and Most Ancient Dog Has Just Been Re-Discovered in the Wild


The first sighting in more than half a century.

After decades of fearing that the New Guinea highland wild dog had gone extinct in its native habitat, researchers have finally confirmed the existence of a healthy, viable population, hidden in one of the most remote and inhospitable regions on Earth.

According to DNA analysis, these are the most ancient and primitive canids in existence, and a recent expedition to New Guinea’s remote central mountain spine has resulted in more than 100 photographs of at least 15 wild individuals, including males, females, and pups, thriving in isolation and far from human contact.

 “The discovery and confirmation of the highland wild dog for the first time in over half a century is not only exciting, but an incredible opportunity for science,” says the group behind the discovery, the New Guinea Highland Wild Dog Foundation (NGHWDF).

“The 2016 Expedition was able to locate, observe, gather documentation and biological samples, and confirm through DNA testing that at least some specimens still exist and thrive in the highlands of New Guinea.”

If you’re not familiar with these handsome creatures, until now, New Guinea highland wild dogs were only known from two promising but unconfirmed photographs in recent years – one taken in 2005, and the other in 2012.

They had not been documented with certainty in their native range in over half a century, and experts feared that what was left of the ancient dogs had dwindled to extinction.

But maybe they were just really good at hiding?

Last year, a NGHWDF expedition made it to the Papua province of western New Guinea, which is bordered by Papua New Guinea to the east and the West Papua province to the west.

 Led by zoologist James K McIntyre, the expedition ran into local researchers from the University of Papua, who were also on the trail of the elusive dogs.

A muddy paw print in September 2016 finally gave them what they were looking for – recent signs that something distinctly dog-like was wandering the dense forests of the New Guinea highlands, some 3,460 to 4,400 metres (11,351 to 14,435 feet) above sea level.

Trail cameras were immediately deployed throughout the area, so they could monitor bait sites around the clock. The cameras captured more than 140 images of wild Highland Wild Dog in just two days on Puncak Jaya – the highest summit of Mount Carstensz, and the tallest island peak in the world.

dogPregnant female.

new-guinea-pupsHighland wild dog pups.

The team was also able to observe and document dogs in the area first-hand, and DNA analysis of faecal samples have confirmed their relationship to Australian dingos and New Guinea singing dogs – the captive-bred variants of the New Guinea highland wild dog.

Due to the lack of evidence of the species, it’s been unclear exactly how dingoes, singing dogs, and highland wild dogs actually relate to one another, but that’s a question that will hopefully soon be answered, because these animals truly are our best bet for getting a better understanding of canid evolution.

As the NGHWD explains:

“The fossil record indicates the species established itself on the island at least 6,000 years ago, believed to have arrived with human migrants. However, new evidence suggests they may have migrated independently of humans.

While the taxonomy and phylogenetic relationships with related breeds and Australian dingoes is currently controversial and under review for both New Guinea singing dogs and highland wild dogs, the scientific and historical importance of the highland wild dog remains critical to understanding canid evolution, canid and human co-evolution and migrations, and human ecology and settlement derived from the study of canids and canid evolution.”

As far as dogs go, you’d be hard-pressed to find a more attractive one – their coats are most commonly golden, but there are also black and tan, and cream variants. Their tails are carried high over their backsides in a fish hook shape, like a Shiba Inu.

In all of the dogs observed so far, their ears sit erect and triangular on the top of the head.

dog-variantsSome of the wild dog sightings. 

running-dogA wary observer. 

Though it’s yet to be confirmed, the highland wild dogs could make the same unique vocalisations of their captive-bred counterparts – the New Guinea singing dogs.

According to the NGHWDF, there are roughly 300 New Guinea singing dogs remaining in the world, living in zoos, private facilities, and private homes, and they’re known for their high-pitched howls, which they will perform in chorus with one another, and sometimes for several minutes at a time:

 The research into these amazing dogs is ongoing, and a scientific paper on the discovery is expected to be released in the coming months.

And the good news is the researchers are optimistic of the highland wild dogs’ chances of survival.

Local mining companies have been tasked with taking special environmental stewardship measures to protect the remote area and ecosystem surrounding their facilities, which means they have “inadvertently created a sanctuary in which the HWD could thrive”, says the NGHWDF.

Soure:sciencealert.com

The Amount of Food Spiders Eat Each Year Will Haunt You for the Rest of Your Life


Spiders are already horrifying, with their eight beady little eyes and spindly legs and sticky webs. They also probably eat more meat than your mind can wrap your head around—more meat than humans eat, even.
 Spider meal specialist Martin Nyffeler of the University of Basel, Switzerland decided, hey, let’s try and estimate the total weight of all of the food spiders around the world eat per year. Some data crunching resulted in a number so bafflingly high you’ll either squirm or thank the spiders for keeping us safe from all the other bugs. Maybe both.

That number: The world’s estimated 25 million metric tons of spiders eat between 300 and 800 million metric tons of food per year, according to estimates published today in the very silly-sounding journal The Science of Nature. (That almost feels like calling something the Ferrari of Lamborghinis in academic journal speak). That food consists mainly of insects, little non-insect bugs called springtails, and even small vertebrates. The researchers make several assessments, using the amount of food individual spiders need to eat, the number of insects they catch in their webs, and the number of insects they kill on the hunt.

The 300 to 800 million metric ton figure is pretty close to the mass of meat and fish humans eat per year—around 400 metric tons, according to the paper. It’s also equal to the mass of humans: There are 7.4 billion people on earth, and the average human’s weight is around 130 pounds. Converted to metric tons, that’s a bit over 400 million.

 The idea to do this eye-opening calculation came from a book Nyffeler read 40 years ago, The World of Spiders by arachnologist William Bristowe in 1958, according to a prepared statement he passed along to Gizmodo. “In this book, Bristowe speculated that the weight of insects annually killed by the British spider population would exceed the combined weight of the British human population,” wrote Nyffeler. “This statement fascinated me very much. I decided that I would like to find out if Bristowe was correct with his speculation.”

You might think this means spiders are helping our crops by eating all of the pests, but that doesn’t seem to be the case. “Instead spiders appear to play a significant ecological role as predators of insects in forests and undisturbed grasslands,” Nyffeler wrote. Very generally speaking, spiders don’t seem to eat as many bugs in agricultural areas because these heavily managed systems don’t have as many or as good an assortment of prey.

Our apologies for that horrible image. But hey, at least they aren’t eating you. Yet.

Source:The Science of Nature

A new hypothesis of dinosaur relationships and early dinosaur evolution.


http://www.nature.com/articles/nature21700.epdf?shared_access_token=wWbPp9i0ayNUOMDM3guieNRgN0jAjWel9jnR3ZoTv0M90DUzIj8q5jPeCtoSdpixH6OYZOIXl8EqiIH6Dw4foZQUO3VABRKeiusHHJIqMuhLCkQcU95Md7NH4gnaOiyGG6YN5kR7Po9DYGrMTaTXbQyfz_cmsLwRU3J_n0DHbmc%3D

Source:http://www.nature.com

Major United States University Proposes First-Ever “Bee Vaccines” In Order to Save Declining Population.


The plight of the bees has gotten more attention in the past few years, as people are finally getting the memo that saving our pollinator species is of the utmost importance.

Already, the monarch butterfly has been “decimated” by agricultural chemicals according to scientist and TV host Bill Nye, in large part because of the widespread over use of synthetic pesticides and neonicotinoid seed coatings.

Now, one major U.S. university is proposing a radical solution for saving the bees and restoring their health: the first-ever bee vaccinations.

Vaccinate the Bees to Protect Them From Disease?

According to a sponsored report by Arizona State University that recently ran on USAToday.com, the first-ever bee vaccinations are being researched by Gro Amdam, an ASU School of Life Sciences professor, with help of researchers from Finland and Norway.

The report notes that 87 of the top 115 food crops require pollination, and includes numbers of the staggering “worker” honeybee decline. Since 1940, the numbers have dropped from 6 million to 2.5 million hives today.

 bee vaccines created asu

If successfully developed, the vaccines would utilize a “key carrier of environmental bacteria” that is digested by queen bees when they eat royal jelly, called Vitellogenin. The substance is referred to in the report as a way of “naturally vaccinating” the next generation of bees by acting as a shuttle for bacterial pieces.

“As humans, we protect ourselves against devastating bacterial infections via vaccination … These vaccines … provide long-term protection because our bodies develop a physiological memory of the bacterial material in the vaccines. In contrast, everybody thought insects could not be vaccinated because insects do not have physiology that allows the immune system to have memories,” Amdam said.

The team is also experimenting with oral vaccines that contain the substance.

 “We develop vaccines with bacterial pieces that are given to queens and study the physiology that allows the vaccines to be effective,” she said. A grant has been received to continue the research until 2021, and the team is also looking into the benefits of potentially launching a large-scale bee vaccine program.

While the possibility of vaccinating bees may seem like an outlandish one to many in light of the common sense initiatives (including banning neonicotinoids or GMOs and limiting pesticide use like Europe has done), it is worth noting that the report also mentions herbicides, fungicides, and other toxic chemicals as part of the reason for the bee decline and colony collapse disorder.

The hope among many in the pro-organic and non-GMO movement is that by limiting these and other toxic agricultural practices, and switching to organic and other more holistic and natural methods of farming, the bee population can rebound without the use of labor intensive, expensive, and unproven pie-in-the-sky potential “solutions” like bee vaccination.

 

Scientists turn spinach leaf into working heart tissue


Worcester Polytechnic Institute Grows Heart Tissue on Spinach Leaves
Spinach is good for your heart 

Researchers have managed to turn a spinach leaf into working heart tissue and are on the way to solving the problem of recreating the tiny, branching networks of blood vessels in human tissue.

Until now, scientists have unsuccessfully tried to use 3D printing to recreate these intricate networks.

Now, with this breakthrough, it seems turning plants with their delicate veins into human tissue could be the key to delivering blood via a vascular system into the new tissue.

 Scientists have managed in the past to create small-scale artificial samples of human tissue, but they have struggled to create it on a large scale, which is what would be needed to treat injury.

Researchers have suggested that eventually this technique could be used to grow layers of healthy heart muscle to treat patients who have suffered a heart attack.

Watch the video. URL:

Plants and animals of course have very different ways of transporting chemicals around the body.

However, the networks by which they do so are quite similar.

The authors of the study are publishing their findings in research journal Biomaterials in May

The scientists, from the Worcester Polytechnic Institute wrote: “The development of decellularized plants for scaffolding opens up the potential for a new branch of science that investigates the mimicry between plant and animal.”

In order to create the artificial heart, the scientists stripped the plant cells from the spinach leaves, sending fluids and microbeads similar to human blood cells through the spinach vessels and then “seeded” the human cells which are used to line blood vessels into it.

 Glenn Gaudette, professor of biomedical engineering at Worcester Polytechnic Institute, said:  “We have a lot more work to do, but so far this is very promising.

“Adapting abundant plants that farmers have been cultivating for thousands of years for use in tissue engineering could solve a host of problems limiting the field.”

Source:http://www.telegraph.co.uk/

This mesmerising time-lapse of cell division is real, and it’s spectacular.


This is life.

 If you’ve ever wondered what cell division actually looks like, this incredible time-lapse by francischeefilms on YouTube gives you the best view we’ve ever seen, showing a real-life tadpole egg dividing from four cells into several million in the space of just 20 seconds.
 Of course, that’s lightening speed compared to how long it actually takes – according to Adam Clark Estes at Gizmodo, the time-lapse has sped up 33 hours of painstaking division into mere seconds for our viewing pleasure.

The species you see developing here is Rana temporaria, the common frog, which lays 1,000 to 2,000 eggs at a time in shallow, fresh water ponds.

According to the team behind the footage, they had to build their own equipment to film it like this, and had to devise a way to get the lighting and microscope set-up just right.

“The whole microscope sits on anti-vibration table. [I]t doesn’t matter too much what microscope people use to perform this,” francischeefilms describe on their YouTube page.

“There are countless other variables involved in performing this tricky shot, such as: the ambient temperature during shooting; the time at which the eggs were collected; the handling skills of the operator; the type of water used; lenses; quality of camera etc.”

Check out the footage. URL:https://youtu.be/Wz4igVjNGq4

Source:http://www.sciencealert.com

Scientists Have Figured out How Life Is Able to Survive


IN BRIEF
  • A new sequencing technique that maps out and analyzes DNA damage demonstrates how bacterial cells function in two critical excision repair proteins.
  • The team’s research and discovery not only heralds the use of this new mapping technique, it could also pave the way for a solution that will help address antibiotic resistance.

DNA-REPAIR SYSTEMS

Every day, the DNA in our cells gets damaged. This might sound scary, but it’s actually a normal occurrence – which makes DNA’s ability to repair itself vital to our survival. Now, scientists are beginning to better understand exactly how these repairs happen. A new sequencing technique that maps out and analyzes DNA damage demonstrates how bacterial cells function in two critical excision repair proteins: Mfd and UvrD.

The process, called nucleotide excision repair, has been used by a team from the UNC School of Medicine to gain a deeper insight into the key molecular functions of these repair systems, including the proteins’ roles in living cells. This repair process is known for fixing a common form of DNA damage called the “bulky adduct,” where a toxin or ultraviolet (UV) radiation chemically modifies the DNA.

The technique, called XR-seq lets the scientists isolate and sequence sections of DNA with the bulky adduct, thus allowing them to identify its actual locations in the genome. It has previously been used to generate a UV repair map of the human genome, as well as a map for the anticancer cisplatin drug.

For this study, scientists used the same method to repair damage caused by E. coli. As co-author of the study, Christopher P. Selby, PhD explained:

When the DNA of a bacterial gene is being transcribed into RNA, and the molecular machinery of transcription gets stuck at a bulky adduct, Mfd appears on the scene, recruits other repair proteins that snip away the damaged section of DNA, and “un-sticks” the transcription machinery so that it can resume its work. This Mfd-guided process is called transcription-coupled repair, and it accounts for a much higher rate of excision repair on strands of DNA that are being actively transcribed.

A POTENTIAL SOLUTION

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Chris Selby, PhD; Aziz Sancar, MD, PhD; and Ogun Adebali, PhD

In further experiments, the researchers defined the role of an accessory excision repair protein in E. coli – UvrD, which helps clear away each excised segment of damaged DNA. Essentially, think of Mfd as the DNA “un-sticker” and UvrD as the “unwinder.” Using the XR-seq method, scientists discovered evidence of transcription-coupled repair in normal cells, but not in cells without Mfd—implying that the protein played a key role in its repair process.

The team’s research and discovery not only heralds the use of this new mapping technique, it could also pave the way for a solution that will help address the pressing, global threat of antibiotic resistance.

“If we fail to address this problem quickly and comprehensively, antimicrobial resistance will make providing high quality universal health coverage more difficult, if not impossible,” the UN Secretary-General Ban Ki-moon said. “[Antibiotic resistance] a fundamental, long-term threat to human health, sustainable food production and development.”

To support their current research, the team now plans to study XR-seq in bacterial, human and mammalian cells, to better understand the excision repair process.

Source:futurism.com

We Now Have a Mathematical Formula to Explain How Sperm Swim


The first formula we ever forget.

 The rhythmic back and forth motions that make up a sperm’s swimming movement can be explained by a mathematical formula, according to new research.

Scientists analysed the beat of individual sperm tails (called flagella) to reconstruct their waveform mathematically. By understanding how individual sperm travel through fluid, the researchers say it will help us figure out how larger groups of sperm behave and interact – something that could be crucial for developing treatments for male infertility.

 Researchers are able to study sperm movement thanks to the power of microscopic magnification, but the technique doesn’t allow us to analyse sperm group behaviour – partly because there’s just so many of the tiny sperm cells vying for a single egg.

“Around 55 million spermatozoa are found in a given sample, so it is understandably very difficult to model how they move simultaneously,” explains mathematician Hermes Gadêlha from the University of York in the UK.

“We wanted to create a mathematical formula that would simplify how we address this problem and make it easier to predict how large numbers of sperm swim. This would help us understand why some sperm succeed and others fail.”

135949237-sperm-1Kyoto University

To capture the swimming motions, the team filmed a sample from a human sperm donor under the microscope at almost 300 frames per second.

This data was then fed into a computer, which analysed the beat of the sperm’s tail and generated a waveform of the tiny cells’ flagellar movements.

 The team was then able to reconstruct the waveform mathematically, with a formula that recreates the beats and helps us understand how the sperm’s swimming motion impacts the flow of fluid around it.

According to the researchers, sperm pushes itself forward with a contradictory, jerky movement that simultaneously pulls the head backwards and sideways.

“You would assume that the jerky movements of the sperm would have a very random impact on the fluid flow around it, making it even more difficult for competing sperm cells to navigate through it, but in fact you see well defined patterns forming in the fluid around the sperm,” explains Gadêlha.

In particular, the whip-like motion of the flagellum that pulls the head backwards and sideways is able to counter some of the friction that sperm encounter as they swim through flowing fluid.

“This suggests that to achieve [locomotion], sperm stirs the fluid around in a very coordinated way… not too dissimilar to the way in which magnetic fields are formed around magnets,” Gadêlha says.

“So although the fluid drag makes it very difficult for the sperm to make forward motion, it does coordinate with its rhythmic movements to ensure that only a few selected ones achieve forward propulsion.”

Now that these movements have been recreated in a formula, the team says it will be easier to calculate how fluid flows can affect large groups of sperm, which could help scientists examine why some men’s sperm don’t swim strongly enough to fertilise an egg.

The next step for the researchers will be to do just that, applying their model to see how it goes at predicting the movement of larger numbers of sperm cells.

Depending on the results, we may discover insights that could help with developing treatments for male infertility problems – giving these tiny swimmers the little nudge they need to get where they’re going.

“It is true when scientists say how miraculous it is that a sperm ever reaches an egg,” says Gadêlha, “but the human body has a very sophisticated system of making sure the right cells come together.”

Source:http://www.sciencealert.com

One of the Oldest Questions in Biology Is Finally at Its End: Why Do Organisms Reproduce Sexually?


Article Image
A sperm approaches the egg.

Biologists have been speculating on the reason why such a complicated process for reproduction, sex, became the most common mode for advanced organisms, particularly when asexual reproduction has so many advantages. It is easier, faster, uses a lot less energy, a mate is not required, and the result is an offspring which is fully matured, and can protect and care for itself. With sexual reproduction, finding a mate can be challenging. Once the risky business of impregnation and birth have taken place, protecting and caring for the baby remains difficult, leaving families open to attack from challengers and predators.

Single celled organisms such as bacteria reproduce asexually. Among complex organisms, many plants and even some animals do too. These include bananas, starfish, and even komodo dragons. Despite this, up to 99% of complex organisms reproduce sexually, at least some of the time. So it must convey some type of advantage.

Dr. Stuart Auld and colleagues at the University of Stirling in Scotland wanted to explore further. Auld is among the Faculty of Natural Sciences at the university. He said that this question is one of the oldest in evolutionary biology. What’s more, sex’s presence is pervasive in nature. “Sex explains the presence of the peacock’s tail, the stag’s antlers and the male bird of paradise’s elaborate dance,” Auld said.

Organisms go through a lot to find a mate and reproduce sexually. How does it benefit them?

German evolutionary biologist August Weismann in 1886 proposed that sex was a way to hasten evolution. Beneficial mutations could be introduced quickly, while those which were harmful would be sloughed off. Sex also allows for different combinations of genes which can help organisms evolve rapidly to fit new situations. A theory, developed by Leigh Van Valen in the late 1980s, called the “Red Queen Hypothesis,” is now the prevailing one. This was taken from the character in Through the Looking Glass, more commonly known as Alice in Wonderland.

When Alice meets the Red Queen, she must take part in a bizarre chess game, where she runs as fast as she can in order to keep up with the other players. This constant running to maintain position is the theme the hypothesis adopts. Organisms react not only to the environment but each other. When one organism develops an adaptation that gives it an advantage, it affects its predator, and prey.

Lions for instance depend on the antelope population. Should antelope develop the ability to run faster through a rapid mutation, the lion population would come under pressure. Only when lions developed the ability to run faster or to pounce farther would a balance be struck. There exists a similar arms race between host organisms and their parasites. But since single cells organisms don’t live too long, pathogens must evolve rapidly or face extinction. Meanwhile, a host organism needs to evolve just as quickly to resist infection.

The water flea is one of those rare species which reproduces both sexually and asexually.

To hasten evolution, the right combination of genes is required. So the more combinations an organism has access to, the better its chances. Though a strong theory, it’s been difficult to test. After all, how do you compare those organisms who reproduce sexually to those who don’t? Auld and colleagues found a way.

 Published in the journal Royal Society Proceedings B, researchers found that at the time when sexual reproduction came on the scene, “parasites adapted to infect the previous generations.” Therefore, reproducing sexually meant seriously undermining the parasites’ ability to cause infection. Auld and colleagues selected the water flea, a bizarre creature which reproduces both sexually and asexually. Just a few others organisms do, such as yeast and the snail.

The water fleas used in this experiment were collected from the natural environment, as were their bacterial parasites. After a period, researchers gathered female water flea offspring who were produced either sexually or through cloning. Under controlled conditions, they exposed the offspring to the parasites. Those who reproduced sexually were twice as resistant to infection, researchers found. According to Dr. Auld, these findings suggest that, “The ever-present need to evade disease can explain why sex persists in the natural world in spite of the costs.”

Watch the video discussion. URL:https://youtu.be/gRpEt61XM4M

Source:http://bigthink.com

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