A bad break for fake pearls

Genetic fingerprinting of pearls

2013-10-16

(Press-News.org) For a long time, it was thought impossible to isolate a pearl's genetic material. Now, a Swiss research team has achieved this elusive goal. Scientists Joana Meyer, from the ETH Institute of Integrative Biology group headed by Prof. Bruce McDonald, and Laurent Cartier of the Swiss Gemmological Institute (SSEF), under the direction of Michael Krzemnicki, succeeded for the first time in extracting trace amounts of DNA from a variety of cultured pearls in an almost non-destructive way. Using the genetic code, they were able to differentiate pearls from three different species of oysters vital to the jewellery trade. Their results were recently published in the scientific journal PLoS ONE.

The genetic material is likely embedded in organic matter found in the calcium carbonate matrix of the pearl, as well as in random pockets of organic matter enclosed in the pearl. The tiny amount of DNA recovered was sufficient to determine the species of pearl oyster that produced the jewel in question. The examined pearls were South Sea pearls originating from the species Pinctada maxima, Tahitian pearls from Pinctada margaritifera and pearls from Akoya oysters. This last group is one of the most important producers of both cultured and natural pearls (Pinctada radiata). These naturally formed gems can be very valuable and often come from the Arabian Gulf.

Non-destructive sampling

An important part of the project was to develop a technique for isolating pearl DNA without destroying the commercial value of the jewels. The researchers used a fine drill to expand existing holes in a barely visible way. The resulting 10 milligrams of drilled-out material was sufficient to isolate enough DNA for the purpose of species identification.

A patent application has already been filed for the method developed by the research team. In the future, it will be possible to use it to differentiate between various kinds of pearls and to provide better documentation of historical speci-mens. This will give dealers and owners of pearl jewellery greater transparency and certainty regarding a pearl's source.

In a next phase, the researchers envision using the pearl DNA to determine a pearl's local origin, potentially allowing jewellers and owners to identify the region or even the specific lagoon in which a pearl was produced.

Age determination with radiocarbon dating

In a parallel research partnership between ETH Zurich and the SSEF, Irka Hajdas from the Laboratory for Ion Beam Physics at ETH Zurich and Michael Krzemnicki from the SSEF sought to determine the age of pearls using radio-carbon dating. This involved measuring the ratio of radioactive carbon (14C) to normal carbon (12C) in the nacre. This study, which was published in the scientific journal Radiocarbon, demonstrated how the true age of pearls can be de-termined using the 14C method. This method can help clarify whether a historical piece of jewellery is an antique or a forgery made of modern cultured pearls.

Identifying forgeries

Pearls are among the oldest jewels used by humans. Natural pearls, which form randomly in the mantle tissue of molluscs, are especially valuable. It is often necessary to break open thousands of shells to find a single natural pearl. Cultured pearls have been commercially available only since 1910, but have been produced in massive quantities since then. In 2012, China alone produced more than a billion pearls for the jewellery market, most of which were cultured pearls from freshwater molluscs.

Determining the type of pearl in a piece of jewellery and its age and origin are becoming increasingly important for the trade in both historical natural pearls and modern cultured pearls. These new technologies will make it easier to expose frauds and forgeries.

### END

ELSE PRESS RELEASES FROM THIS DATE:

Low-voiced men love 'em and leave 'em, yet still attract more women: Study

2013-10-16

Men with low-pitched voices have an advantage in attracting women, even though women know they're not likely to stick around for long. Researchers at McMaster University have found that women were more attracted to men with masculine voices, at least for short-term relationships. Those men were also seen as more likely to cheat and unsuitable for a longer relationship, such as marriage. The study, published online in the journal Personality and Individual Differences, offers insight into the evolution of the human voice and how we choose our mates. "The sound ...

Antibiotic use to treat catheter-associated bacteriuria futile in decreasing risk of mortality

2013-10-16

With 30 million indwelling bladder catheters placed annually nationwide, patients face an increased risk of developing catheter-associated bacteriuria (bacteria in the urine). Many patients with indwelling urinary catheters acquire bacteria in the urinary tract while they are catheterized. Most previous studies assessing morbidity and mortality associated with catheter use have not separated urinary tract infection from asymptomatic bacteriuria. This has made it difficult to determine if bacteria in the urine puts patients at higher risk for bloodstream infection or death. ...

Genetic alterations show promise in diagnosis and treatment of bladder cancer

2013-10-16

October 16, 2013, Shenzhen, China---A Chinese research team composed of Shenzhen Second People's Hospital, BGI and other institutes reports their latest study on bladder cancer genomics that was published online in Nature Genetics. The discoveries were made using whole-genome and exome sequencing technologies and provide evidence that genetic alterations affecting the sister chromatid cohesion and segregation (SCCS) process may be involved in bladder tumorigenesis and open a new way for the treatment of bladder cancer. Transitional cell carcinoma (TCC) is the most common ...

Misinterpretation of study

2013-10-16

The actual aim of the study was to find out whether cats are more stressed when they live in large groups together or, whether the strict hierarchy of larger groups reduces stress. Neither could be confirmed in the present study, which was published in the journal Physiology & Behavior. The number of cats per household had no influence on the stress of the animals. Rather, stress in domestic cats depends more on the socialization of the animals, on the relationship with humans, on the space available to them or on the access to food. Every cat feels and reacts differently The ...

Quantum particles find safety in numbers

2013-10-16

Ludwig-Maximilians-Universitaet (LMU) in Munich researchers have uncovered a novel effect that, in principle, offers a means of stabilizing quantum systems against decoherence. The discovery could represent a major step forward for quantum information processing. The laws of classical physics provide an adequate description of how our Universe behaves on the macroscopic scales that are accessible to our everyday experience. In the world of classical mechanics, the state of a physical system and its future evolution is fully determined by the instantaneous locations and ...

How do ADHD medications work?

2013-10-16

Philadelphia, PA, October 16, 2013 – There is a swirling controversy regarding the suspicion that medications prescribed for the treatment of ADHD (attention-deficit/hyperactivity disorder) primarily act to control disruptive behavior as opposed to having primary effects on the ability to attend to the environment. Thus, there is a continued need to better understand the neural basis of ADHD medication effects. A new study in Biological Psychiatry now provides evidence that methylphenidate and atomoxetine, two FDA-approved medications for the treatment of ADHD, both ...

Glowing neurons reveal networked link between brain, whiskers

2013-10-16

DURHAM, N.C. -- Human fingertips have several types of sensory neurons that are responsible for relaying touch signals to the central nervous system. Scientists have long believed these neurons followed a linear path to the brain with a "labeled-lines" structure. But new research on mouse whiskers from Duke University reveals a surprise -- at the fine scale, the sensory system's wiring diagram doesn't have a set pattern. And it's probably the case that no two people's touch sensory systems are wired exactly the same at the detailed level, according to Fan Wang, Ph.D., ...

Defining the graphene family tree

2013-10-16

Oxford, October 16, 2013 - There has been an intense research interest in all two-dimensional (2D) forms of carbon since Geim and Novoselov's discovery of graphene in 2004. But as the number of such publications rise, so does the level of inconsistency in naming the material of interest. The isolated, single-atom-thick sheet universally referred to as "graphene" may have a clear definition, but when referring to related 2D sheet-like or flake-like carbon forms, many authors have simply defined their own terms to describe their product. This has led to confusion within ...

Cuckoos impersonate hawks by matching their 'outfits'

2013-10-16

New research shows that cuckoos have striped or "barred" feathers that resemble local birds of prey, such as sparrowhawks, that may be used to frighten birds into briefly fleeing their nest in order to lay their parasitic eggs. By using the latest digital image analysis techniques, and accounting for "bird vision" - by converting images to the spectral sensitivity of birds - researchers have been able to show for the first time that the barred patterns on a cuckoo's breast may allow it to impersonate dangerous birds of prey. This might enable cuckoos to frighten other ...

Ancient Syrians favored buying local to outsourcing production

2013-10-16

An archaeologist at the University of Sheffield has found evidence that, contrary to a widely held theory, ancient Syrians made their stone tools locally instead of importing finished tools from Turkey. The discovery, newly published online in Journal of Archaeological Science, has implications for our understanding of how early cities developed in these regions and how the geographic origins of raw materials affect developing states. During the Early Bronze Age, around 5300 to 3100 years ago, blades made of chert and obsidian remained important despite the advent ...

Modular assembly of chiral nitrogen-bridged rings achieved by palladium-catalyzed diastereoselective and enantioselective cascade cyclization reactions

Sally C. Morton, executive vice president of ASU Knowledge Enterprise, presents a bold and practical framework for moving research from discovery to real-world impact

Biochemical parameters in patients with diabetic nephropathy versus individuals with diabetes alone, non-diabetic nephropathy, and healthy controls

Muscular strength and mortality in women ages 63 to 99

[Press-News.org] A bad break for fake pearls
Genetic fingerprinting of pearls

A bad break for fake pearls

ELSE PRESS RELEASES FROM THIS DATE:

LAST 30 PRESS RELEASES: