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Undiscovered Secrets of Evolution from a Horse

Undiscovered Secrets of Evolution from a Horse

It sounds like Jurassic Park—scientists recover DNA from a long-dead animal in the hopes of understanding more about how it lived.  This week, scientists announced that they had sequenced and reconstructed the genome of a horse that died 700,000 years ago.  Their research has revealed significant new findings about the evolution of horses and donkeys, and may open the door to new research using prehistoric genomes.

Until recently, scientists who wanted to understand the evolution of animals over time had only one option for records: fossils.  While fossils extend further back in time than genome study can, they have some flaws that render them less than ideal for understanding the particulars of species evolution.

For one thing, scientists working to reconstruct the history of a species using fossils are hampered by an inevitably incomplete fossil record.  Fossils themselves are often also incomplete or damaged, and it can sometimes be difficult for researchers to determine which parts of a fossil's differences are due to species changes and which are due to individual variation.

Studying the genome of ancient organisms gives a significantly more detailed look at exactly how species have changed over time.  By comparing the 700,000 year old horse genome with more recent horse DNA, scientists revealed that the ancestor of horses and donkeys actually evolved two million years earlier than previously thought.

While genomics allows unprecedented insight into how creatures evolved in relatively recent biological history, Jurassic Park dreamers should take note: the scientists who sequenced the genome of the ancient horse believe that there is no way for enough DNA to be preserved for sequencing in any creature that died more than about 1 million years ago.  Until this most recent genomic sequencing, the earliest genome that had been analyzed belonged to a human who died about 70,000 years ago.

The horse DNA from what is now known as the Thistle Creek Horse was recovered from a bone that had been preserved by being buried beneath volcanic ash in what is now Canada's Yukon Territory.  Intensely cold permafrost conditions also contributed to the preservation of genetic material.  DNA from several other species, including a pre-domestication horse from 43,000 years ago, modern domesticated horses, and the last known wild horse population left on Earth.

According to the results of the genomic analysis, the modern wild horses analyzed have not cross-bred with domesticated horses, and represent a significantly different genetic population.  Researchers also determined that horse populations have shifted significantly with climate patterns, increasing in population during cold times and dying off during warmer periods.

Effects of Air Pollution on Super Storms

Effects of Air Pollution on Super Storms

Air pollution is rarely thought of as being good for human beings, but new research shows that even smog clouds may have a silver lining.  According to a study published in the journal Nature Geoscience, hurricanes and other major tropical storm systems may be suppressed to some degree by human-generated air pollution.

With climatologists increasingly concerned about the frequency of hurricanes—especially Atlantic “superstorms” like last year's Hurricane Sandy—the paper may shed some light on why tropical storms in the last decade have been so frequent and so devastating.

Researchers from the UK's meteorological service used a new type of computer modeling to understand the effects of airborne pollutants on storm systems.  While older computer models were only capable of keeping track of a few variables, like temperature and wind, the newer model also incorporates aerosol particles of several types.  Because this type of modeling is relatively new, the results of the study remain open to interpretation and may require revision as the model is strengthened over time.

One of the most influential of these aerosol particles is sulfur dioxide, which is commonly released when fossil fuels are burned.  When sulfur dioxide is absorbed into clouds, it changes the way that those clouds form and even changes the rain into acid rain, which can damage buildings and infrastructure.

According to researchers, sulfur dioxide also influences how much sunlight can be reflected from clouds, which in turn affects how much solar energy is put into storm systems overall.  The more energy that a storm system has, the more strong it will be and the more likely it is to have significant damaging effects on coastal regions.

Researchers, who have studied the changes in hurricane patterns from 1860 to today, now believe that storm cycles may have been kept artificially suppressed in the early to mid-20th century.  As laws went into effect in the late 20th century to prevent air pollution and reduce the levels of sulfur dioxide in the atmosphere, these levels declined, leading to a significant increase in both the number and intensity of tropical cyclones.

If these researchers are correct, the current level of Atlantic hurricanes may actually be much closer to the natural level of hurricanes expected, rather than being historically anomalous.  This may also indicate that even if global warming levels off or even begins to be reversed, the temperature changes may not have as much of an impact on tropical cyclone formation as airborne pollutants.

USDA in Preventing World Famine from Spreading

USDA in Preventing World Famine from Spreading

The United States Department of Agriculture announced in a press release this week that U.S. laboratories have found a gene that may be able to stop the spread of wheat stem rust, a reddish fungus that could cause widespread famine if left unchecked.

Wheat stem rust, a disease caused by infectious microfungi, has been observed in Africa and the Middle East.  In areas affected by the disease, crop yields have been reduced by as much as 70 percent, making wheat rust a devastating organism for farmers who rely on wheat crops in those regions.

Many scientists fear that wheat stem rust could soon infect wheat crops overseas, including in North America, which could significantly impact food supplies worldwide.  Over 90 percent of the world's wheat crops are vulnerable to the specific species of fungus that causes wheat stem rust, and the organism is fast-spreading in new areas.  After being reported for the first time only 14 years ago, in 1999, the disease has spread from a localized patch of Uganda to many of its neighbors and beyond.

New research conducted at the Cereal Disease Laboratory in St. Paul examined not just the species of wheat typically grown for bread and pastas, but also several other related species to see if a gene could be found to create wheat stem rust resistance.  Scientists working at the laboratory found exactly the gene they were looking for—termed Sr35—in a species of wheat called Triticum monococcum.  This species is closely related to the wheat grown for food crops today.

Now that the gene has been isolated from Triticum monococcum, scientists say that it can be inserted into the genome of commercial varieties of wheat.  This can be done through genetic engineering or even through cross-breeding.  Plants carrying the Sr35 gene have near-complete immunity to wheat stem rust.

The USDA says that some commercial varieties of wheat have already begun to use the new Sr35 gene, and that it is beginning to be deployed by wheat geneticists nationwide.  While it is likely that wheat stem rust would not begin to impact North America for some time—possibly decades—having prevention measures in place now ensures the safety and security of America's wheat crop.

By working to prevent diseases before they become an issue to the United States food supply, the USDA is also creating disease resistant strains that can be deployed to regions already affected by wheat stem rust.

Caesarean Section Statistics Show Major Changes

Caesarean Section Statistics Show Major Changes

Atlanta, GA—A new report by the Centers for Disease Control in Atlanta shows that pregnant women in the United States no longer face an increasing rate of caesarean section in United States hospitals.

For many women, this is good news: most doctors and experts believe that the current rate of caesareans being performed in the United States is significantly higher than it needs to be to promote optimal newborn and maternal health.  While about 1 in 3 births today in the United States takes place via caesarean delivery, in 1970 the numbers were far lower, at only one birth in every 20.

After a steep rise for 12 years, the caesarean rate in the United States has now held steady for two years in a row.  Because caesareans involve a significantly higher risk of substantial complications, including infections and even death, many doctors were concerned that the high rates of c-section delivery were having negative impacts on the health of women and children.

Even more worrisome to experts was a trend toward earlier c-sections, often at 38 or 39 weeks, before full-term gestation.  The new CDC report shows that this trend, as well, seems to be reversing: the number of c-sections performed at 38 or 39 weeks has actually begun to decline over the last two years.

According to the statistics generated by the report, the decline in early caesarean section was experienced by women across all age groups, as well as all ethnicities and races.  It was not immediately clear why the decline occurred.  Because much of the increase in caesarean sections took place due to elective c-section procedures, it may be that fewer mothers are requesting these surgeries, and even fewer requesting that they be performed prior to the due date.

The decline may also have stopped because fewer hospitals are prohibiting vaginal deliveries after a previous caesarean section.  Hospital policy on these “VBAC” births varies regionally and even between hospitals in the same area.

While this decline is good for babies and mothers alike, experts caution that the United States still has a long way to go before its caesarean rate is optimal.  Midwives are often able to achieve caesarean section rates of less than five percent in their practices.  Goals set by the ACOG, the country's largest organization of gynecologists and obstetricians, aim to eventually reduce the caesarean rate to 15 percent of total births.

New Mission to Study the Sun: IRIS Satellite Launched by NASA

New Mission to Study the Sun: IRIS Satellite Launched by NASA

Vandenberg Air Force Base, CA—Your parents may have told you not to stare at the sun, but soon, NASA will be doing just that from a satellite called Iris, or the Interface Region Imaging Spectrograph.

The satellite, launched on the evening of June 27, is designed to study only one specific region of the sun, the chromosphere.  The chromosphere is the solar region located between the sun's surface and its corona.  According to NASA scientists, the region that Iris will study is thought to be responsible for solar wind.

Solar wind, rather than being a stream of air like wind on Earth, is like a wind made of ionized gases.  Occasionally, solar winds become explosive, erupting into phenomena called Coronal Mass Ejections, or CMEs.  These CMEs are so powerful that they have significant effects on Earth.

When a large CME occurs, the particles released by the eruption can cause intense auroral displays on Earth days later.  However, they have a sinister side as well: the delicate arrays of communications technologies that make the globally connected world possible are prone to outages due to these flare-ups.

The Iris satellite is designed to help scientists understand the region that solar wind and CMEs emerge from, in order to potentially develop an earlier warning system for CME events.  Using an ultraviolet telescope, scientists will be able to take a detailed look at the temperature gradients of the sun and understand it with more precision than ever before.  Current telescopes pointed toward the sun are tasked with looking at the entire surface, rather than just the chromosphere.

Scientists working with Iris also hope to shed light on one of our solar system's most enduring mysteries: why the sun is hotter far above its surface than on the surface itself.  Today, several competing theories exist to explain this phenomenon, and NASA scientists hope that Iris will be able to gather enough data to determine which theory—if any—is the correct one.

Iris was launched into space by a Pegasus rocket, and will start gathering solar data for 24 months after 2 months of instrument checks and testing.  By the time its mission is completed, scientists should have a significantly better idea of why the sun acts the way that it does, and how to tell when solar weather is about to have a major impact here on Earth.  The project is expected to cost $180 million.

Source: NASA.gov 

Voyager Spacecraft At Edge of Solar System

Voyager Spacecraft At Edge of Solar System

While astronomers still do not know exactly when the Voyager 1 spacecraft will enter interstellar space completely, they say that current data suggests it is now in the outermost layer of our solar system and could leave it at any time.

Scientists working on the Voyager project, launched in 1977 to explore the worlds in our solar system before leaving it to do the first research in interstellar space, say that the craft is nearing a momentous point in its journey.  Since the launch of Voyager 1 and 2, scientists have debated where the heliopause—the border between the solar system and interstellar space beyond it—is located and how to determine what the true edge of the solar system is.

In 2004, scientists saw the first signs that Voyager 1 was leaving the realm of the solar system, after encountering a layer called the “termination shock” where solar winds become turbulent instead of flowing in a directed stream of particles.  Since then, several layers have come and gone, and at each one, the Voyager probe can detect less and less of the sun's influence.

Currently, scientists say their data has shown two major signs that Voyager is beyond the solar system.  First, charged particles from the sun have begun to disappear.  Scientists believe the particles are being brought back into the solar system and are not able to go as far out as Voyager has now traveled.  Second, particles from other solar systems and interstellar space have now begun to bombard the probe at a significantly higher rate, indicating that our solar system is no longer shielding Voyager from the cosmic rays and other types of radiation being emitted by other stars.

However, in spite of these signs that Voyager is now outside of the sun's influence when it comes to particles and radiation, one thing hasn't changed: the magnetic fields experienced by the probe.  Currently, Voyager's instruments indicate that the magnetic fields it is detecting still come from the sun, rather than from interstellar space.

Scientists expect that there will be a distinct border where the magnetic fields shift, delineating the final border between our solar system and interstellar space.  However, because no previous probes have been so far from Earth, no one knows exactly when Voyager will encounter this milestone.  Scientists estimate that it could be only weeks or months away, but could be as far away as several years if the heliopause is even further from the sun than had previously been predicted.

Source: NASA.gov

Your Own T-Rex Dinosaur in Your Home

Your Own T-Rex Dinosaur in Your Home

The Smithsonian's National Museum of Natural History has amassed an incredible collection of fossils, but one of the most iconic dinosaurs in the world wasn't there.  Now, under a loan agreement from the U.S. Army Corps of Engineers, the Smithsonian will have a Tyrannosaurus Rex of its very own.

The National Museum of National History is scheduled to re-open its Dinosaur Hall in 2019, and just revealed that its centerpiece will be the Wankel T-Rex, a nearly complete skeleton that has until now been housed at the Museum of the Rockies in Bozeman, Montana.  The Wankel skeleton is named for rancher Kathy Wankel, who discovered the first bones of the fossil in 1988 on federal land in eastern Montana.  After a two-year process of uncovering and removing the skeleton, it was loaned to Montana State University, where the Museum of the Rockies is located.

Under the terms of the lease agreement, the U.S. Army Corps of Engineers, which has owned the fossilized skeleton since its discovery, will loan the Wankel T-Rex to the National Museum for 50 years.  The Museum of the Rockies will obtain another almost complete T-Rex skeleton to replace the Wankel T-Rex in its collection.

Because the museum won't be opening the new dinosaur exhibit for another five years, curators say that portions of the T-Rex skeleton will be displayed in various places in the museum during the planned renovation.

The Smithsonian says that once the T-Rex fossil is on display, it will become the most widely viewed Tyrannosaurus in the world, with over 7 million annual visitors coming to see it.  Today, the museum has plaster and plastic reproductions of T-Rex skeletons, but does not have any actual fossilized remains.  With the addition of the Wankel skeleton, they will now have a T-Rex that is between 80 and 85 percent complete.

In order to transport the fossil across the United States, a special shock-absorbing truck trailer will be used.  The fossil is scheduled to arrive at the Smithsonian on National Fossil Day—October 16.  In 2014, the museum plans to host a temporary exhibit to welcome the T-Rex skeleton, and has sent archaeological crews to North Dakota who will work to gather other fossils of creatures and even plants that lived in the same era as the dinosaur.

Tyrannosaurus skeletons have been found primarily in Canada and the Great Plains region of the United States.  The Tyrannosaurus lived approximately 65 million years ago, when those regions were substantially warmer.

Animals Poisoned by World War II Toxins

Animals Poisoned by World War II Toxins

The fisher, a threatened mammal species related to weasels, has lived in the Sierra National Forest for far longer than there has been human habitation in North America.  Recent research, however, shows that a very human vice may be threatening the fisher population in Northern California.

In 2009, researchers report, a male fisher was necropsied after being found dead in the national forest.  Toxological screening showed that the cause of death for the fisher was acute poisoning from a commercial rodenticide.

When scientists realized that the fisher had been poisoned, they started looking back at other fishers that had been recovered in the park in previous years.  Rodenticide was present in 85 percent of the total fishers.

However, the scientists were initially unsure of what caused the rodenticide to be present in the first place.  Typically, the only places that rodenticides are used are agricultural and urban environments.  Because the Sierra National Forest is generally considered to be undeveloped land, risks to fishers from rodenticides were thought to be low.

According to scientists writing in the journal Conservation Letters, the culprit was illegal marijuana farming.  While California has broadened its medical marijuana laws to allow some dispensary activity, federal raids on marijuana dispensaries and farms have resulted in illegal cultivation continuing, sometimes on federal lands like the Sierra National Park.

In order to keep rats and other animals from eating the marijuana crop, growers use large quantities of anticoagulant rodent poisons.  Many of the toxins developed to create these rodenticides were originally designed as nerve poisons during World War II.  Today, however, these toxins find their way into the soil and water around the cultivation sites, poisoning other animals.  While the fisher is a carnivore, its prey is contaminated with the poisons.

When the fisher eats prey that contains the anticoagulant toxins, scientists say they will not necessarily die right away.  Often, they will be weakened or made ill by small amounts of the poison, leaving them more vulnerable to their natural predators.  Most of the animals studied that tested positive for toxins had been killed by predators, rather than dying directly of the toxin's effects.

U.S. Forest Service wildlife ecologists said that illicit growing operations may be a factor in animal deaths that is often overlooked, because previously weakened animals are likely to be considered dead from predation if they display wounds from predators.  The study shows that it may also be necessary to do toxicology screenings on these animals to make sure that they were not harmed by the effects of nearby poisons.

Brave New World: Controversial DNA Embrionic Therapy

Brave New World: Controversial DNA Embrionic Therapy

England's chief medical officer has given the go-ahead to a new procedure that would help around ten couples in the UK every year prevent significant genetic problems in their sons and daughters.  The technique has generated controversy because it requires creating an embryo using three different donors—in effect, three biological parents.

While human embryos are created when a sperm from one parent and an egg from the other combine, the egg actually contains two types of DNA information.  In addition to containing 23 chromosomes, the mitochondria in the egg—its energy processing centers—have their own DNA that is handed down the maternal line.

When something goes wrong in that DNA, it means that every cell in the body will develop problems with processing energy.  This leads to a variety of serious, often fatal disorders.  Because the issue with energy processing occurs at such a basic level, treatments for these diseases are extremely limited and typically consist of symptom management.  Rather than focusing research on trying to find a cure for these diseases, which may prove impossible, the new technique focuses on helping families avoid passing on mitochondrial defects.

The three-parent technique would allow parents who had previously been unable to have healthy or surviving children, due to defects in mitochondrial DNA, to conceive healthy children using in vitro fertilization techniques.  The vast majority of the DNA in the resulting child would belong to the child's two parents.  Only the very small amount of DNA kept in the mitochondria—just 37 genes in total—would be replaced.  In contrast, the main sperm and egg donor parents would be contributing over 20,000 genes of their own.

Ethical concerns have been raised about the procedure.  Those who protest the three-parent IVF technique are typically not concerned with this specific procedure, but rather with the desire to modify the genetics of an embryo to eliminate problems.  Dr. David King of Human Genetics Alert told the BBC that he is concerned that the use of these techniques will create a slippery slope leading to a “eugenic designer baby market.”

However, the UK's governmental health authorities have approved the procedure for now.  They believe that the overall potential for abuse is low, but will continue to monitor any children born after being conceived with the mitochondrial DNA replacement technique, to ensure that the procedure does not have any unintended effects.  According to governmental guidelines published this week, children born following the procedure would not be informed about their mitochondrial DNA donor and would have no legal connection to the third biological parent.

Early Retirements for Chimpanzees

Early Retirements for Chimpanzees

In a move that drew criticism from some research groups and applause from animal rights activists, the National Institutes of Health announced this week that it would follow guidelines from an independent review to retire most of the chimpanzees currently being used in NIH-funded research projects.

While the vast majority of scientific research on animals today is conducted on other types of animals, 451 chimpanzees are research animals in NIH-funded facilities today.  After the announcement this week, the NIH plans to retain only 50 of these animals for potential future research.  The remaining chimps would be placed into sanctuary spaces that were designed to meet their needs for socialization and intellectual stimulation.

The director of the NIH, Dr. Francis S. Collins, say that the NIH believes that “new scientific methods and technologies have rendered [chimpanzees'] use in research largely unnecessary.”  The only research projects that will now be approved to use chimpanzees will have to meet a set of rigorous criteria. 

Scientists hoping to use chimps in research according to the new guidelines will be required to show that their research could not be done without the use of chimps.  They will also need to provide the chimpanzees with significantly more space than any current laboratory uses, and will need to house them in groups of at least seven.  Chimpanzees, which are social creatures, can become depressed or aggressive when deprived of contact with others of their species.

As part of the plan to put most of the remaining chimpanzees into sanctuaries, six of the existing nine chimp research projects funded by the NIH will be shut down, while the other three will be allowed to wind down more gradually.

The Texas Biomedical Research Institute, a laboratory that currently uses approximately 20 percent of the total chimpanzees used in research in the United States, says that the reduction may be a mistake, and calls the planned 50 chimp reserve an “arbitrarily chosen number.”

Scientists with the Institute caution that because the guidelines call for the reserve chimpanzees not to be bred, research using chimpanzees will become more difficult over time.  Furthermore, they point to the example of Hepatitis C—a disease that only exists in chimpanzees and humans—as a reason that chimpanzees may continue to be needed for research purposes.

A lack of sanctuary space means that while the chimps will be retired to sanctuaries as much as possible, some may need to continue to be housed in laboratories, which will have space repurposed for chimp retirement.