Thursday, June 27, 2013

Scientists decode the genome of a 700,000 year old horse, breaking the record for oldest genome sequenced and increasing our understanding of horse evolution.

The prehistoric equine DNA came from a 15 cm (6 inch) long leg bone, partly preserved by the freezing temperatures of the Yukon Territory, Western Canada, where it was found. Though the bone was degraded and host to several other organisms like bacteria, advanced techniques and computer software enabled the team to extract, prepare and sequence the ancient horse DNA in unprecedented detail.

The genome was compared with the genomes of other members of the horse family, including zebras, donkeys and wild Asian horses. These results revealed that the ancestor of the Equus genus (the genus all living horses belong to) branched off from other lineages 4-4.5 million years ago.

The DNA samples also revealed that a Mongolian equine, Przewalski’s horse, is the last living breed of wild horse. This endangered species is an offshoot of the domestic horse lineage and diverged about 50,000 years ago. The team were also able to tell that horse population size fluctuated with the climate and that olfaction and a strong immune system have continually been selected for.

What does this mean for reading the genomes of other extinct animals? Though the limit's been pushed back, time elapsed is still a very important factor. The conditions the remains were buried in are also critical - permafrost preserves DNA far better than tropical conditions do. In addition, DNA previously thought too small or decayed to be usable could still be sequenced. If we're lucky, the genomes of our ancestors may not be as out of reach as we thought.

Photo: Przewalski’s horse (Equus ferus przewalskii). Credit to Michael Nichols, National Geographic.

http://www.nature.com/news/first-horses-arose-4-million-years-ago-1.13261

http://www.wired.com/wiredscience/2013/06/ancient-horse-genome/

http://news.nationalgeographic.com/news/2013/06/130626-ancient-dna-oldest-sequenced-horse-paleontology-science/

http://blogs.scientificamerican.com/observations/2013/06/26/horse-fossil-yields-astonishingly-old-genomeare-similarly-ancient-human-genomes-next/
Unfortunately, the chemical treatment is expensive so it will not be used in clean-up efforts in the near future. It is likely to see more immediate use in industrial applications.

More info: http://bit.ly/124j9PR

Photo from Ind. Eng. Chem. Res.
I have no idea how anyone found this out, but it's completely true. You don't even necessarily need to have a red light. Apparently, the brain is addicted to sensation. So when all sensation is blocked out, the brain creates its own!

A few more tricks to play on your own brain here: http://bit.ly/1agKeaH

James Lovelock and the Gaia hypothesis - New Scientist

James Lovelock and the Gaia hypothesis - New Scientist

Binary babel: Fixing computing's coding bugs - tech - 11 June 2013 - New Scientist

Binary babel: Fixing computing's coding bugs - tech - 11 June 2013 - New Scientist
Natural Selection 
Barryl


Natural Selection is part of the Biological Evolution process. Genetic permutations caused by chance,climatic and catastrophic factors, etc., determine the quality of the offspring ( and may be variations of it,  such as mutations, which may result in new species) of/from an organism. Natural selection determines what stays and continue to pro-create = successful adaptation of the organism to the environment at the time of prevailing conditions in the biosphere). As biospheric conditions are not constant over very long periods,  means that organisms may be severely stressed to adapt (selection) or die (become extinct).  Catastrophic phenomena are part of Nature and so is human intervention - good and bad.
Poor male dark fishing spiders. The very act of mating sends them into a comatose state, following which they're eaten by the female. Losing your virginity is a death sentence.

To copulate with a female, a male dark fishing spider (Dolomedes tenebrosus) coats his pedipalps (the two "legs" closest to his face, left) in sperm and inserts one into the female and inflates a bulb within. During this process his legs curl up under him and he becomes immobile. Two hours later, he dies - if the female hasn't already liquified and eaten him.

Though it sounds counter-productive, being eaten can actually increase a male's chance of fathering offspring. In other spider species, it's known that a sated female will produce healthier offspring and is less likely to mate with another male.

These events happen when the male gets to mate, but sometimes he won't even get that far. If a male doesn't follow the foreplay rules, the larger female will eat him. If he accidentally inflates one of his pedipalp bulbs, immobility and death follow. Once inflated the bulb can't be deflated, and the researchers believe it is this genital mutilation that results in the male's death (rather than any act of the female, as noted in other species).

A separate experiment revealed that males have preference for virgin females. If exposed to the silk of virgin and non-virgin females, the male will spend more time looking for the virgin female. If mating's going to cost them their life, they may as well try and make sure they weren't mating with a female who'd already fertilized her eggs.

To read the paper: http://bit.ly/17CwA1C

Photo credit: Rob Swatski/Flickr/CC BY-NC 2.0.

http://www.wired.co.uk/news/archive/2013-06/20/spider-sex

http://phys.org/news/2013-06-male-dark-fishing-spiders-die.html

Monday, June 24, 2013

Unlike most multicellular organisms, bacteria reproduce asexually - meaning that no genetic material is exchanged during reproduction. Instead, they're capable of gene transfer, where one bacterial cell will insert some of their genetic material into another. This method of gene transfer is often responsible for bacterial populations rapid evolution.

Now, a study has found that some bacteria are capable of inserting their genetic materia into human genomes - and interestingly, it was found to be more common in cancerous cells.

More information: http://bit.ly/132z5Zf

The Science of Why We Don’t Believe Science — Editor's Picks — Medium

The Science of Why We Don’t Believe Science — Editor's Picks — Medium

Sunday, June 23, 2013

Evolution added a photo from June 22, 2013 to their timeline.
Rhino are poached in the hundreds every year. One of the main reasons for this the Asian medicine industry. Rhino horns are believed to be miracle cures for everything from cancer to erectile dysfunction. (In reality, there is no evidence that rhino horn helps at all. They are composed of keratin, the same stuff as your fingernails.) The huge demand for the horns causes the above-mentioned poaching.

South Africa in particular has been hit hard by poaching. It has more rhino* than many other countries in Africa. Although they are more successful in breeding, the South African rhino are targeted by poachers. More often than not, the rhino are killed or seriously injured as their horns are chopped off and they are left to die.

A group of vets has taken up the challenge of trying to rescue the few rhino that survive the ordeal. Although many of these vets do this voluntarily, the cost of their efforts is extremely high. Dr William Fowlds, South Africa’s leading rhino vet is actively involved in such efforts. He assists other vets in South Africa with managing rhino that survive poaching attacks. In his words "This year alone South Africa has lost more than 2.5 rhino per day. Most of the poaching occurs in the northern Kruger National Park, a park the size of Israel... Trained rangers put their lives at risk, for very little salary.”

Dr Fowlds is assisted by veterinary pathologist Prof Fred Reyers from the University of Lincoln in the UK. He analyses the blood-work of the injured rhino in order to aid the vets treating them. He says that when rhino are shot with rifles, they are severely stunned, which allows poachers to remove the horn from the rhino. The injuries that they sustain from getting shot can often result in infection. Furthermore, if the injured rhino falls onto its side, the sheer mass of the animal cuts off blood flow from the lower side of its body, causing muscle death. Poachers are also known to use tranquiliser dart guns to immobilize the rhino. Most of the time, an antidote is not administered.

The injuries from the bullet wounds, the lesions from the removal of the horn and the degradation of the muscles in the rhino all contribute to sepsis developing in the rhino. This results in internal damage to vital organs like the kidneys and lungs. As such, it is impossible to accurately gauge the seriousness of the injury from an external perspective. So, Prof Reyers analyses blood-work to get a clear idea of the severity of the rhinos’ condition so that the on-site vets can adjust their treatments accordingly.

As Dr Fowlds says, “These living dinosaurs are truly iconic symbols of our successes and failures as custodians of this planet. The current rhino situation is a dying testimony of our conservation efforts."

*Yes, the plural of ‘Rhino’ is ‘Rhino’…

Read all about it: http://bit.ly/1c6cmtu
Image URL: http://bit.ly/184hrT7

Saturday, June 22, 2013

Edward Snowden's live Q&A: eight things we learned | World news | guardian.co.uk

Edward Snowden's live Q&A: eight things we learned | World news | guardian.co.uk

How to Survive a Heart Attack when Alone : My Health List

How to Survive a Heart Attack when Alone : My Health List
Bacteria inside bacteria inside bugs, a symbiotic happy family.

Citrus mealybugs (Planococcus citri), which look a bit like white woodlice, feed on plant sap. However plant sap doesn't provide all the nutrients they need, which is where the bacteria come into play. Tremblaya princeps (which lives inside the mealybug) and Moranella endobia (which lives inside Tremblaya) work symbiotically with the mealybug to provide the nutrients it needs.

Given that Moranella lives inside Tremblaya, you can guess which is larger. Their genomes, however, go the other way - Tremblaya's is only 120 genes long, and the smallest genome of any bacterium. Moranella's is almost 4 times as long. Tremblaya is also missing genes essential for survival, with Moranella picking up the slack for its bacterium host.

How can Tremblaya's genome have become so small? The researchers wondered if it had transferred them to its mealybug host, but investigation revealed something even stranger. The mealybug's genome does contain genes from bacteria, but these aren't from Tremblaya or Moranella - they're from 3 separate bacteria types, and none of those three live in the mealybug today.

So really, it's bacteria inside bacteria inside insects, using genes from 3 bacteria species that aren't there.

The international team hope their work will help us understand how organelles, such as the mitochondria in our cells, came to be. These started out as symbiotic bacteria before becoming the cell powerhouses they are for us. The mealybug/Tremblaya/Moranella interactions may be one pathway bacteria can take to becoming vital parts of cells.

Photo credit: USDA ARS Photo Unit

Further reading and sources:
http://www.sciencedaily.com/releases/2013/06/130620142954.htm

http://www.livescience.com/37597-bugs-house-russian-doll-bacteria.html

http://phenomena.nationalgeographic.com/2013/06/20/snug-as-a-bug-in-a-bug-in-a-bug/

Friday, June 21, 2013

Poop, not parasites | The Bug Geek

Poop, not parasites | The Bug Geek

The Myth of the Supermoon - Observing Blog - SkyandTelescope.com

The Myth of the Supermoon - Observing Blog - SkyandTelescope.com

Silver Boosts Antibiotic Efficacy | The Scientist Magazine®

Silver Boosts Antibiotic Efficacy | The Scientist Magazine®
Evolution added a photo from June 21, 2013 to their timeline.
New research reveals the origin of The Hoff - the Hoff yeti crab, that is.

When these crabs were found in 2011, their hairy chests reminded researchers of David Hasselhoff. These hairs trap bacteria where it can be "farmed" until the crab scrapes it off with its comb-like mouthparts and eats it. The crabs live in the deep sea, more than 2000m down, and live around hydrothermal vents where they can feed their bacteria in the mineral-rich vent water. It's a fine line between being close enough to reach minerals and getting boiled alive in the 380°C (716 Fahrenheit) water.

It was previously thought that yeti crabs were "living fossils", but new research shows all four yeti crab species have a common ancestor around 35-40 million years ago. DNA analysis suggests the crabs originated around vents in the eastern Pacific Ocean and migrated west, with larvae hitching rides in fast-moving ocean currents.

Current vent species can be traced back around 55 million years to a period of global warming, when the atmosphere warmed and deep sea oxygen levels dropped. This could have killed off the vent species of the time and cleared the way for yeti crabs to move in.

"Yeti crabs and other such creatures may in fact be especially prone to extinction when there is less oxygen available in the deep ocean,’ says Dr Nicolai Roterman (of Oxford University, UK). "This is because if deep-sea ocean oxygen levels fall, the amount of oxygen available to these animals - which already live in an oxygen-poor environment at the limits of their physiological tolerance - may drop below the minimum level at which they can survive. They would face the stark choice of "suffocate or starve"."

To read the paper: http://bit.ly/14mtvwq

Photo: Close-up of "The Hoff" Yeti crab (credit to David Shale). Colonies of crabs around heat vents on the East Scotia Ridge in the Southern Ocean (CHESSO Consortium).

http://www.ox.ac.uk/media/news_stories/2013/130619.html

http://www.livescience.com/37532-yeti-crab-evolution.html

http://www.bbc.co.uk/news/science-environment-22952728

Busy bee eaters! Birds fight, mate and nest together during annual migration through Africa | Mail Online

Busy bee eaters! Birds fight, mate and nest together during annual migration through Africa | Mail Online

Thursday, June 20, 2013

Evolution We can only imagine being cancer-proof, but for naked mole rats it's reality. New research is lifting the curtain on how they've attained cancer immunity. It turns out mole rats can thank a substance named hyaluronan for their immunity. This sugar holds cells and tissues together and makes skin elastic (remember that later). Other animals, including us, posses hyaluronan, but mole rats produce a large amounts of long chains of it (over 5 times bigger than ours). These chains form a cage around cells, preventing potentially cancerous cells from replicating, and also controlling cell growth. Experiments revealed that without hyaluronan, mole rats cells could become cancerous. It's suggested that naked mole rats have cancer-resistance as a side effect of evolving stretchy skin. Not having fur means that their skin receives a great deal of stress when burrowing - without very stretchy skin and flexible tissue, they could cause themselves injury. This selection pressure gave them more and longer hyaluronan and as a consequence, cancer immunity. Other mechanisms may be at work as well as hyaluronan. The mole rat's genome has revealed several cancer-related genes that differ between them and other vertebrates. Similarly previous studies have suggested other mechanisms. "By looking at this completely weird and unusual organism, we can find some novel mechanisms that apply across mammals," said Chris Faulkes (Queen Mary, University of London). "Understanding some of these amazing things could have broad applicability for human health... It's possible that one day some of the cool features of the animals could be engineered into humans. But we may all end up looking like naked mole rats." Photo credit: Brandon Vick/University of Rochester. http://www.nature.com/news/simple-molecule-prevents-mole-rats-from-getting-cancer-1.13236 http://www.livescience.com/37555-cancer-resistance-naked-mole-rats.html http://www.newscientist.com/article/mg21829224.800-naked-mole-rats-reveal-why-they-are-immune-to-cancer.html#.UcMJKfmZO8A http://phenomena.nationalgeographic.com/2013/06/19/why-naked-mole-rats-dont-get-cancer/ We can only imagine being cancer-proof, but for naked mole rats it's reality. New research is lifting the curtain on how they've attained cancer immunity. It turns out mole rats can thank a substance named hyaluronan for their immunity. This sugar holds cells and tissues together and makes skin elastic (remember that later). Other animals, including us, posses hyaluronan, but mole rats produce a large amounts of long chains of it (over 5 times bigger than ours). These chains form a cage around cells, preventing potentially cancerous cells from replicating, and also controlling cell growth. Experiments revealed that without hyaluronan, mole rats cells could become cancerous. It's suggested that naked mole rats have cancer-resistance as a side effect of evolving stretchy skin. Not having fur means that their skin receives a great deal of stress when burrowing - without very stretchy skin and flexible tissue, they could cause themselves injury. This selection pressure gave them more and longer hyaluronan and as a consequence, cancer immunity. Other mechanisms may be at work as well as hyaluronan. The mole rat's genome has revealed several cancer-related genes that differ between them and other vertebrates. Similarly previous studies have suggested other mechanisms. "By looking at this completely weird and unusual organism, we can find some novel mechanisms that apply across mammals," said Chris Faulkes (Queen Mary, University of London). "Understanding some of these amazing things could have broad applicability for human health... It's possible that one day some of the cool features of the animals could be engineered into humans. But we may all end up looking like naked mole rats." Photo credit: Brandon Vick/University of Rochester. http://www.nature.com/news/simple-molecule-prevents-mole-rats-from-getting-cancer-1.13236 http://www.livescience.com/37555-cancer-resistance-naked-mole-rats.html http://www.newscientist.com/article/mg21829224.800-naked-mole-rats-reveal-why-they-are-immune-to-cancer.html#.UcMJKfmZO8A http://phenomena.nationalgeographic.com/2013/06/19/why-naked-mole-rats-dont-get-cancer/

Sunday, June 16, 2013

Ever wondered how whales can stay underwater for so long? Scientists from the University of Liverpool might be able to tell you the answer!

Myoglobin is an oxygen-binding protein which gives meat its reddish colour. In elite diving mammals (such as whales), the concentration of myoglobin in muscle tissue is so high that the muscle is almost black in colour. However, at such high concentrations, proteins tend to aggregate together, which deteriorates their function. Up till now, not much was known about how mammalian divers overcame this obstacle.

The researchers took an in-depth (no pun intended) look at the “electrical charge on the surface of” the myoglobin molecule. They noticed that mammals that spent longer periods underwater had a greater amount of electrical charge on the surface of the myoglobin molecule. This trend even applied to semi aquatic mammals! This suggests that the electrical charges in the molecules cause them to repel one another, effectively cancelling out the aggregation problem. So with higher electrical charge on the molecules, a diving mammal can afford to have a higher concentration of myoglobin in muscles.

After identifying this molecular signature, the researchers mapped it out on the mammalian phylogenetic tree. Then, they reconstructed the muscle oxygen stores, and therefore diving capacity, of extinct ancestors of modern mammals. This in-turn allows us to understand the predatory opportunities that existed in ancient aquatic habitats.

From a medical perspective, this research is also important because it could help us understand diseases such as diabetes and Alzheimer’s, where the proteins’ clumping together becomes a problem. It can also aid in the creation of artificial blood substitutes, where protein aggregation must be taken into account.

Read all about it: http://bit.ly/19w6ayi
Image URL: http://bit.ly/19GJ1EU

Thursday, June 13, 2013

Evolution added a photo from June 13, 2013 to their timeline.
Even though it's the fastest land animal on the planet, it's not actually speed that's key to a cheetah's hunt. New research reveals cheetahs rely more on their extreme agility and maneuverability to bring down their prey.

The speed of cheetahs has been subject to scientific debate. Measurements taken in the '60s clocked them reaching speeds of 64 mph, but subsequent investigations only measured them hitting 40 mph (about the speed of a greyhound). These studies were also carried out with captive cheetahs, meaning they could tell us little about how cheetahs really used their speed in the wild.

To find out what these cats are really capable of, a team of researchers tracked the movements of 5 wild cheetahs with collars. These collars monitored speed, acceleration, deceleration and location and collected 367 runs over 17 months.

The researchers were surprised to find out agility and maneuverability were more important than speed during a hunt. They were capable of very high speeds (one, called Ferrari, was clocked at 58mph) but the average top speed taken was 33mph, and even this was only maintained for a few seconds. There was also very little difference in speed between successful and failed hunts.

The data revealed, however, that the big cats are champions at rapid acceleration and deceleration. Cheetahs can speed up or slow down by 9mph in a single stride. Their muscle power output per kilogram (100 watts) during acceleration is the highest of any land animal - for comparison, Usain Bolt can produce 25 watts. Speeding up and slowly down rapidly are more important in catching prey than simple speed.

Conventional wisdom also painted cheetahs as dawn hunters, staying within open grasslands. The new data overturns this: the cheetahs hunted during during the day too and half the runs occurred among shrubs, trees and heavy vegetation.

Photo: Cheetah wearing a tracking collar. Credit to Structure & Motion Lab, RVC.

http://www.livescience.com/37372-cheetah-running-hunting-behavior.html

http://phenomena.nationalgeographic.com/2013/06/12/collars-reveal-why-just-how-extreme-cheetahs-can-be/

http://news.sciencemag.org/sciencenow/2013/06/cheetah-agility-more-important-t.html

http://www.nature.com/news/speed-test-for-wild-cheetahs-1.13179

Do Christians have more to lose?

Do Christians have more to lose?

Wednesday, June 12, 2013

Evolution added a photo from June 12, 2013 to their timeline.
New videos of oarfish in their native habitat reveal more about this strange and elusive fish.

The giant oarfish (Regalecus glesne) is the largest of the bony fish. They have been recorded at lengths of 8 metres (26 feet), but it's been suggested they could reach lengths of 15 metres (nearly 50 feet). Several myths surround oarfish; they've been suggested as the origin of "sea serpent" legends and are considered a bad omen in Japan.

Currently there is a lot we don't know about oarfish. The specimens available for study have typically been washed up onto the beach/shallow water and are either dead or dying. While these specimens can tell us about oarfish anatomy, they are of little help in studying aspects like behaviour.

That's one of the reasons these videos, recorded near the Gulf of Mexico, are so exciting. They offer a rare high-quality glimpse into the life of an oarfish in its habitat. Five videos were taken between 2008 and 2011. The videos reveal a lot about oarfish - they can be found nearly 500 metres deep (over 1,600 feet) and can hang almost vertically in the water. Undulation of their long dorsal fin allows them precise control of movement, but they can also undulate their whole body when they require speed.

The highest-quality video revealed the oarfish had company. Clinging to its dorsal spine was a parasitic isopod (imagine a giant underwater pillbug/woodlouse). Given that the oarfish did not immediately flee the ROV (sticking around for nearly 10 minutes), the team believe it has few natural predators.

See one of the videos here (good stuff starts nearly 5 minutes in): http://www.youtube.com/watch?v=-yIWfCAC5y0

Image: Still from one of the videos. Credit to Mark Benfield/Journal of Fish Biology.

http://www.livescience.com/37327-video-deep-sea-oarfish.html

http://news.discovery.com/earth/oceans/rare-sea-serpent-caught-on-video-130610.htm

http://newswatch.nationalgeographic.com/2013/06/11/rare-video-of-giant-sea-serpent-oarfish-caught/

http://deepseanews.com/2013/06/video-of-an-oarfish-in-the-wild/

Tuesday, June 11, 2013

Grandma's Experiences Leave Epigenetic Mark on Your Genes | DiscoverMagazine.com

Grandma's Experiences Leave Epigenetic Mark on Your Genes | DiscoverMagazine.com
Male lyrebirds perform specific dance moves to their songs to attract females.

Lyrebirds, found in Australia, are renowned for their voices. They are fantastic mimics, combining their own sounds with those of the forest (even sounds that naturally wouldn't be there, such as chainsaws and camera shutters). New research has found that superb lyrebirds (Menura novaehollandiae) have particular choreography for certain songs.

Songs are not always accompanied by dances - males only show off their moves to four song types, and each has a different dance. Lyrebirds sometimes mess up and perform the wrong move, a sign that combining singing and dancing could be challenging for them. Moves include behaviours such as hopping, flapping their wings, and fanning and contracting their lyre-shaped tails.

It's been suggested males learn their dances while they are growing up. Males often perform in groups, providing juveniles a chance to learn from adults, and maturity comes at around 7 years of age - likely sufficient time for them to learn how to dance. It's also not known what exactly the females are looking for, or whether moves vary over time and between populations. It's also possible that birds of paradise and manakins have similar dancing skills, but so far no one carried out a study like this with them.

To see the video: http://www.eurekalert.org/multimedia/pub/57148.php?from=241018

To read the paper: http://bit.ly/1bsaOKc

Photo credit: Alex Maisey.

http://www.eurekalert.org/pub_releases/2013-06/cp-slm053013.php

http://www.newscientist.com/article/dn23659-zoologger-the-lyrebird-thats-a-songanddance-man.html

http://www.wired.com/wiredscience/2013/06/superb-lyrebird-dance-moves/

http://www.livescience.com/37219-lyrebirds-sing-and-dance.html

Sunday, June 9, 2013

The term, ‘living fossil’ was initially coined by Charles Darwin to describe creatures that existed for several millions of years in the fossil record, but had changed very little in that time. Famous examples include the coelacanth and the lungfish. Conventionally, sturgeon are considered to be included in this group. But a new study shows that when it comes to change in body size over time, sturgeon have actually been evolving faster than most other fish.

The study, which was published in Nature Communications, shows that sturgeons have evolved a huge variety of sizes, from dwarf sturgeon the size of a bass and some species that can be as big as a car. This is just one result obtained in the study, which looked into the rate of species formation and anatomical variation in fish. To do so, an evolutionary tree linking 7,864 species of fish was assembled. The tree graphed DNA sequence data and body-size information for each species. The researchers actually had to develop brand new programs to process the huge data sets!

Using the raw data and the computer programs, the researchers studied ‘the correlation between how quickly new species form and how rapidly they evolve new body sizes’. Sure enough, a strong correlation was found between species variation and body size evolution across ray-finned fish. Up till now, the evidence for this was largely anecdotal. So, while palaeontologists noticed that groups of organisms with more species tended to have greater anatomical variation, the theory was never rigorously tested.

The fish can mostly be organized into two groups. The first group of fish, which includes the gar, forms species very slowly and has very little variation in body size. The other group, which includes salmon and trout, has fast species formation and a large range of body sizes.

In the words of the lead author, "We're basically validating a lot of ideas that have been out there since Darwin, but which had never been tested at this scale due to lack of data and the limits of existing technologies."

But you’re forgetting the sturgeon! The sturgeon is anomalous in that it does not conform to the general pattern. So, even though there are only 29 species worldwide, their body size is highly varied. Pfft… Hipsters!

Read all about it: http://bit.ly/13JKWXt
Image URL: http://bit.ly/11nblY5

Friday, June 7, 2013

Evolution added a photo from June 7, 2013 to their timeline.
For prairie voles, love is just a matter of gene switches.

Prairie voles (Microtus ochrogaster) have long drawn the attention of neuroscientists due to their monogamous lifestyle. Once a pair of prairie voles mate, they will remain together for the rest of their lives. But what is the mechanism behind this pair-bond?

Previous studies with these voles implicated two neurotransmitters, vasopressin and oxytocin. Mated voles are known to have more receptors for these neurotransmitters than voles who haven't yet mated, and if montane voles (typically a promiscuous species) receive doses of these neurotransmitters they too become monogamous.

This study looked for an epigenetic cause, investigating how mating behaviour changed gene expression (turning them on or off). The team (of Florida State University, Tallahassee) administered a drug to prairie voles that had cohabited for 6 hours but had not mated. This drug blocked a particular enzyme's activity and allowed the genes for vasopressin and oxytocin receptors to be "read".

The results were striking. Though they had not mated, the voles still formed a pair-bond equivalent to if they had. When compared with the brains of mated voles, the brains of cohabited voles showed a similar increase in the number of oxytocin and vasopressin receptors. The drug had created the same changes as mating.

But the drug alone doesn't cause the changes: the voles need the 6 hours together too. Social factors are still very important in creating pair-bonds. This is the first paper demonstrating epigenetic changes underlying these pair-bonds, but the researchers believe they've only touched the tip of the iceberg. The team hope this kind research may lead to a better understanding on epigenetic changes in humans, particularly those brought about by social interactions.

Photo credit: Zuoxin Wang.

http://www.nature.com/news/gene-switches-make-prairie-voles-fall-in-love-1.13112

http://www.the-scientist.com/?articles.view%2FarticleNo%2F35826%2Ftitle%2FEpigenetics-Play-Cupid-for-Prairie-Voles%2F
Want to get involved in some science? The Wildlife Conservation Society wants you to help them track the 17-years-in-the-making emergence of cicadas.

After spending 17 years underground, periodical cicada nymphs emerge for a few short weeks of molting, mating and dying. After this emergence we won't see this brood again until 2030. If you take a photo of cicadas on Instagram, geo-tag the photo with the hashtag #cicadasinmyhood. The WSC plans to collect and compile all these photos to form an interactive map on its website, http://www.wcs.org/cicadas/.

For those who don't use Instagram, you can help the WCS in other ways. You can report sightings at magicicada.org. Another project, Urban Buzz, is looking to receive cicada samples to track body irregularities. Get involved in documenting this brood's emergence!

http://e.wcs.org/site/MessageViewer?em_id=31461.0&dlv_id=42241

Photo credit: Medford Taylor.

http://www.livescience.com/37239-cicadas-surface-on-instagram.html

Thursday, June 6, 2013

Why Rational People Buy Into Conspiracy Theories - NYTimes.com

Why Rational People Buy Into Conspiracy Theories - NYTimes.com
The human placenta is a confounding organ. Made up almost entirely of tissue from the fetus, not the mother, the placenta should be attacked as a foreign invader by the mother’s immune system. And yet, the placenta makes a nine month pregnancy possible. How?

First, a description of the human placenta:

About four to five days after fertilization, the embryo is a hollow ball of about 100 cells (blastocyst). Inside and attached to the hollow ball is a group of cells that will eventually become the fetus, while the outer ball of cells (trophoblast) will attach to the lining of the uterus and become the placenta. The attachment is as close as any two human beings will ever be. Once attached, the trophoblast will actually reroute the mother’s blood supply to feed the fetus, via the umbilical cord. By the time the baby is born, the “interface” between mother and placenta is about 12 square meters.

So how does the placenta keep the mother’s immune system at bay? Researchers found that the placenta releases exosomes: small packages packed with information telling the mother’s immune system to back off. Ian Sargent, a reproductive immunologist at the University of Oxford in England, describes human reproduction: “It’s hijacked the immune system and used it for its own purposes.”

After birth, the placenta is expelled from the mother’s body and the umbilical cord is cut, thus ending the physical connection between mother and child. Controversy over what to do with the placenta after birth (some people think it’s a good idea to eat it) has recently resurfaced in the media. Regardless of what happens to it after those nine months, the placenta is an amazing organ.

Picture courtesy of:

http://www.sciencephoto.com/media/478924/view

Sources:

http://www.sciencenews.org/view/feature/id/350741/description/Life_Support