Shar-pei wrinkles explained by dog geneticists

Just how did the Shar-pei get its famous wrinkled appearance?

Scientists who have analysed the genetics of 10 pedigree dog breeds believe they now have the answer.

Their research identifies 155 distinct locations in the animals' genetic code that could play a role in giving breeds their distinctive appearances.

In the Shar-pei, the team found differences in a gene known as HAS2 which makes an enzyme known to be important in the production of skin.

"There was probably a mutation that arose in that gene that led to a really wrinkly puppy and a breeder said, 'hey, that looks interesting, I'm going to try to selectively breed this trait and make more of these dogs'," explained Joshua Akey from the Department of Genome Sciences at the University of Washington, Seattle, US.

Small differences

The pedigree dog has become a fascination - and a remarkably useful research tool - for geneticists.

The domestication of the grey wolf more than 10,000 years ago, and the selective breeding that followed, has resulted in more than 400 breeds - each with a distinctive physique, coat colour and temperament.

The study compared the genetics of 10 pure-bred dog groups

These discrete populations give scientists the opportunity to compare and contrast the genetics of the different groups, making it easier to find the causes of specific traits.

"Man's best friend" is helping scientists locate the faulty genes that cause disease in both dogs and humans, as well giving a useful insight into how evolution works at a molecular level.

Dr Akey and colleagues studied 32 wrinkled and 18 smooth-coated Shar-peis and compared a specific stretch of their DNA with that of other breeds.

The team found four small, but significant, differences in the genetics of the two skin types of the Shar-pei versus the other breeds. These single nucleotide polymorphisms (SNPs), as they are called, were located in the HAS2 gene.

New targets

"HAS2 makes hyaluronic acid synthase 2, and it's an enzyme that makes hyaluronic acid, and that's one of the principal constituents of the skin," explained Dr Akey.

"There are rare human cases where there are mutations that lead to really severe wrinkling in humans, too.

"So, that suggested it was a good candidate to look at; and sure enough, when we sequenced it we saw that that gene explained wrinkling in Shar-peis," he told BBC News.

Science explained: What is a genome?

As well as giving insights into the Shar-pei, the research has also identified a raft of other locations in the dog genome that can now be investigated further to understand better why pedigree animals look the way they do.

"The thing that excites me most about our study is that in the last five years, five genes have been identified that contribute to this vast diversity in dog breeds," said Dr Akey.

"So our study found all five of those genes and then we found 150 new targets to explore. It's a powerful approach to look at the genetic legacy of selective breeding."

Dr Akey and colleagues report their findings in the Proceedings of the National Academy of Sciences (PNAS).

Having a big bum, hips and thighs 'is healthy'

Carrying extra weight on your hips, bum and thighs is good for your health, protecting against heart and metabolic problems, UK experts have said.

Hip fat mops up harmful fatty acids and contains an anti-inflammatory agent that stops arteries clogging, they say.                                                              

Big behinds are preferable to extra fat around the waistline, which gives no such protection, the Oxford team said.

Science could look to deliberately increase hip fat, they told the International Journal of Obesity.

And in the future, doctors might prescribe ways to redistribute body fat to the hips to protect against cardiovascular and metabolic diseases such as diabetes.

The researchers said having too little fat around the hips can lead to serious metabolic problems, as occurs in Cushing's syndrome.

Shape not weight

Evidence shows that fat around the thighs and backside is harder to shift than fat around the waist.                                                                                                                                                                                       

Although this may sound undesirable, it is actually beneficial because when fat is broken down quickly it releases a lot of cytokines which trigger inflammation in the body, say experts.

These cytokines have been linked to cardiovascular disease, insulin resistance and diabetes.

The slower burning hip fat also makes more of the hormone adiponectin that protects the arteries and promotes better blood sugar control and fat burning.

In comparison, carrying excess fat around the stomach, being "apple shaped", raises the risk of diabetes and heart disease.

Lead researcher Dr Konstantinos Manolopoulos, of Oxford University, said: "It is shape that matters and where the fat gathers.

"Fat around the hips and thighs is good for you but around the tummy is bad."

He said in an ideal world, the more fat around the thighs the better - as long as the tummy stays slim.

"Unfortunately, you tend not to get one without the other," he said.

Fotini Rozakeas of the British Heart Foundation said: "This research helps us better to understand how fat acts in the body in order to develop new approaches in reducing heart and circulatory disease.

"If you are overweight, obese, or if you have a waist size that is increased, it is important to make changes to your lifestyle, such as eating a healthy diet and doing regular physical activity, to reduce your risk of heart health problems."

Ancient map with China at centre goes on show in US

A historic map of the world, with China at its centre, has gone on display at the Library of Congress in Washington.

The map was created by Italian missionary Matteo Ricci in 1602. It is one of only two copies in existence in good condition.

Because of its rarity and fragility - the map is printed on rice paper - the map has become known as the "Impossible Black Tulip of Cartography".

This is the first time it has been on public show in north America.

Ricci created the map at the request of Emperor Wanli who wanted it to help scholars and explorers.

'Revered by Chinese'

The map was purchased by the James Ford Bell Trust in October for $1m (£0.62m), making it the second-most expensive rare map ever sold.

It denotes different parts of the world with annotations and pictures.

The map had China at the centre of the world to underline its importance

In the Americas, for example, several places are named including Chih-Li (Chile), Wa-ti-ma-la (Guatemala) and Ka-na-ta (Canada), and Florida is described as "the Land of the Flowers".

Ford W Bell, a trustee for the James Ford Bell Trust, told the Pittsburgh Tribune-Review newspaper, that the map was "one of the two best in terms of quality, as far as we know".

"Ricci was a very smart missionary. He put China right at the centre of this new universe, this new globe, to underscore its importance," he said.

"Ricci, of course, was the first Westerner to enter Beijing. He was revered by the Chinese, and he was buried there."

The first secretary for cultural affairs at the Chinese embassy in the US, Ti Ban Zhang, said in a statement that the map represents "the momentous first meeting of East and West".

Solar cells made through oil-and-water 'self-assembly'

Researchers have demonstrated a simple, cheap way to create self-assembling electronic devices using a property crucial to salad dressings.

It uses the fact that oil- and water-based liquids do not mix, forming devices from components that align along the boundary between the two.

The idea joins a raft of approaches toward self-assembly, but lends itself particularly well to small components.

The work is reported in Proceedings of the National Academy of Sciences.

Crucially, it could allow the large-scale assembly of high-quality electronic components on materials of just about any type, in contrast to "inkjet printed" electronics or some previous self-assembly techniques.

Specific gravity

Such efforts have until now exploited the effect of gravity, assembling devices through so-called "sedimentation".

In this approach, "blank" devices are etched with depressions to match precisely-shaped components. Simply dumped into a liquid, the components should settle down into the blank device like sand onto a riverbed, in just the right places.

"That's what we tried for at least two years and we were never able to assemble these components with high yield - gravity wasn't working," said Heiko Jacobs of the University of Minnesota, who led the research.

SELF-ASSEMBLY EXPLAINED The oil/water mix contains a number of individual solar cell elements Each is coated with a "water-loving" molecule on the bottom and a "water-hating" one on top The elements align neatly at the oil/water boundary in a two-dimensional sheet The "blank" solar cell has pre-cut places for the elements and is dipped through the boundary As it is slowly drawn upwards, the elements pop into place

"Then we thought if we could concentrate them into a two-dimensional sheet and then have some kind of conveyor belt-like system we could assemble them with high yields and high speed," he told BBC News.

To do that, the team borrowed an idea familiar to fans of vinaigrette: they built their two-dimensional sheets at the border between oil and water.

They first built a device blank as before, with depressions lined with low-temperature solder, designed for individual solar cell elements.

They then prepared the elements - each a silicon and gold stack a few tens of millionths of a metre across - and put different coatings on each side.

On the silicon side, they put a hydrophobic molecule, one that has a strong tendency to evade contact with water. On the gold side, they put a hydrophilic molecule, which has the converse tendency to seek out water.

By getting the densities of the oil- and water-based parts of the experiment just right, a "sheet" of the elements could be made to "float" between the two, pointing in the right direction thanks to their coatings.

The conveyor belt process is to simply dunk the device blank through the boundary and draw it back slowly; the sheet of elements rides up along behind it, each one popping neatly into place as the solder attracts its gold contact.

The team made a working device comprising 64,000 elements in just three minutes.

Bendy future

Having proved that the concept works, the team is now investigating just how small they can go in terms of individual elements, or how large they can go in finished devices.

The approach should also work for almost any material, stiff or flexible, plastic, metal or semiconductor - a promising fact for future display and imaging applications.

Babak Parviz, a nano-engineering professor at the University of Washington in Seattle, said the technique is a "clear demonstration that self-assembly is applicable across size scales".

"Self-assembly is probably the best method for integrating high-performance materials onto unconventional substrates," he told BBC News.

The method tackles what Dr Parviz said is the most challenging problem - the proper alignment of thousands of parts, each thinner than a human hair. But it also works with the highest-performance materials, he said.

"For example, this method allows one to use single-crystal silicon, which is far superior to other types of silicon for making solar cells."

Arctic tern's epic journey mapped

The Arctic tern's extraordinary pole-to-pole migration has been detailed by an international team of scientists.

The researchers fitted the birds with tiny tracking devices to see precisely which routes the animals took on their 70,000km (43,000 miles) round trip.

The study reveals they fly down either the African or Brazilian coasts but then return in an "S"-shaped path up the middle of the Atlantic Ocean.

The long-distance adventure is described in the US journal PNAS.

"From ringing, we knew where the Arctic tern travelled," said Carsten Egevang of the Greenland Institute of Natural Resources.

After setting out (yellow line) the birds pause in the North Atlantic (red circle) to feed. Going home (orange line), they follow the winds Total distance travelled 70,900km On southbound leg: 34,600km Daily progress south: 330km On northbound leg: 25,700km Daily progress north: 520km Within Winter grounds: 10,900km

"The new thing is that we've now been able to track the bird during a full year of migration, all the way from the breeding grounds to the wintering grounds and back again."

The avian world is known for its great migrations.

Albatrosses, godwits, and sooty shearwaters all undertake epic journeys. But none can quite match the Arctic tern's colossal trip.

Starting in August and September, this small bird - which weighs little more than 100g (3.5oz) - will head away from Greenland with the intention of getting to the Weddell Sea, on the shores of Antarctica.

It will spend about four or five months in the deep south before heading back to the far north, arriving home in May or June.

A team from Greenland, Denmark, the US, the UK and Iceland attached small (1.4g/0.05oz) "geolocators" to the animals to find out exactly where they went on this polar round trip.

The devices record light intensity. This gives an estimate of the local day length, and the times of sunrise and sunset; and from this information it is possible to work out a geographical position of the birds.

The geolocators were provided by the British Antarctic Survey (BAS).

"The use of these devices on seabirds is not only revolutionising our understanding of migration patterns, but the resulting data on distribution also help address the requirement to identify important biological hotspots," said Richard Phillips from BAS, a co-author of the PNAS paper.

With such a small bird, the trackers also need to be tiny

The first surprise is that the terns do not make straight for the Antarctic when they leave the Arctic, but make a lengthy stop-over in the middle of the North Atlantic, about 1,000km (620 miles) north of the Azores.

Here, they feed on zooplankton and fish to fuel themselves for the long journey ahead.

"We were able to compare biological productivity in the ocean from satellite imagery and we could see a high productive area that the birds will spend time in," said Mr Egevang.

"Even more importantly, it's the last high productive area before they enter tropical waters where we know productivity is low."

THE LONG DISTANCE FLIER Scientific name: Sterna paradisaea Average wingspan of 75-85cm Breeds in Arctic and sub-Arctic Lays eggs in small ground scrape Feeds on fish and crustaceans Birds live more than 30 years

The birds then head south along the coast of western Europe and western Africa before making a choice, either to continue hugging Africa or sweep across the Atlantic from the Cape Verde Islands to continue the journey along the Brazilian coast.

About half the birds that were tracked decided to take the South American path. It is not clear why, but the researchers believe wind might make either route seem favourable to the terns.

After spending their northern winter months in Antarctic waters, the terns then fly back towards the Arctic.

But rather than retracing their southward flight paths, the birds follow a gigantic "S" pattern up the middle of the Atlantic Ocean.

"This is completely new knowledge," Mr Egevang told BBC News.

"They make a detour of several thousand km but once we start comparing the route to the prevailing wind system, it makes perfect sense - moving in a counter-clockwise direction in the Southern Hemisphere, and clockwise in the Northern Hemisphere.

"It's just more energy-efficient for them to do that even though they are travelling several thousand more km than if they flew in a straight line."