Daily Archives: October 26, 2013

Oct. 25, 2013 Every day, all day, our DNA gets beaten up by chemicals and radiation -- but remarkably, most of us stay healthy. Now, an investigation by a team of French and Canadian researchers has produced insights into a little-studied but common radiation threat to DNA: low-energy electrons (LEEs), with energies of 0-15 electron volts.

The team has devised the first rough model of a close DNA cellular environment under threat from LEEs, revealing for the first time their effects on DNA in natural, biological conditions. Their work appears in The Journal of Chemical Physics, which is produced by AIP Publishing

The team's work is an important step forward in understanding how LEEs injure DNA because it provides a realistic experimental platform for analysis of results. The goal is to use this knowledge to improve current uses of radiation, such as in cancer treatments.

"The way by which these electrons can damage DNA, and how much damage they inflict, quantitatively, is of major importance not only for general radiation protection purposes, but also for improving the efficiency and safety of therapeutic and diagnostic radiation therapy," said Michel Fromm, the lead researcher from Universit de Franche-Comt in Besanon, France, whose expertise is in creating nanometer-scaled DNA layers. His co-author on the paper is Leon Sanche, of Sherbrooke University Qubec, Canada, who is one of the world's leading authorities on LEE research.

The team explored specific features of a small DNA molecule called a plasmid on a specialized thin film they created, which was irradiated by an electron gun. The impact produced transient particles called anions, which dissociate into "pieces" of DNA. When analyzed, these molecular fragments provide insight into the mechanisms of DNA strand breaks and other DNA injuries that health researchers seek to understand, repair and prevent.

"The fascinating point is that each time the close environment of DNA changes, new mechanisms of interaction of LEEs appear," Fromm said.

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Understanding DNA damage from common radiation threat, low-energy electrons

DNA confirms that a child found by police in a Gypsy encampment in central Greece is the daughter of a Bulgarian migrant, who says she gave up her baby because she could not afford to care for her.

Sasha Ruseva, a 35-year-old Bulgarian Gypsy, or Roma, said she gave birth to the girl, called Maria, four years ago while working as an olive picker in Greece.

"The DNA profile showed that Sashka Ruseva is the biological mother and Atanas Rusev is the biological father of the small child called Maria," said Svetlozar Lazarov, the secretary general of Bulgaria's interior minsitry.

The girl was found last week during a crackdown by Greek authorities on Gypsy settlements. Authorities became suspicious of the couple who claimed to be her parents, because of the girl's blonde hair and blue eyes.

"We gave her, we gifted her, without money," Sashka Ruseva told Bulgaria's TV7 on Friday.

Authorities tracked Ruseva to a gypsy camp in Nikolaevo in rural Bulgaria. She was found living with her husband and several other children, in a home without running water. Five of the couple's children also have blonde hair and blue eyes and resemble Maria.

The Greek Gypsy couple, with whom Ruseva left the girl, were arrested last week for child abduction, a claim they deny.

"It confirms what my client was saying. The baby was given to them by the Bulgarian Roma woman because she could not afford to raise her. It's the first time the truth was approved and prosecution dropped abduction charges against my clients today," said Marietta Palavrasa, an attorney defending the Greek couple.

The girl is being cared for by a Greek charity and held at an undisclosed hospital.

Her discovery set off an international search to find her parents, as well as crackdowns across Europe on Gypsy settlements amid rumors that children were being sold or traded.

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Questions Answered: DNA Reveals Girl's Identity

NIKOLAEVO, Bulgaria DNA tests have confirmed that a Bulgarian Roma couple are the parents of a mysterious girl in Greece known as Maria, authorities said Friday.

Genetic profiles of Sasha Ruseva and her husband, Atanas, matched that of the girl, said Svetlozar Lazarov, an Interior Ministry official.

Ruseva has said she gave birth to a baby girl four years ago in Greece while working as an olive picker, and gave the child away because she was too poor to care for her.

12 Photos

Maria has been placed in temporary care since last week after authorities raided a Roma settlement in central Greece and later discovered that girl was not the child of a Greek Roma couple she was living with. The couple has been arrested, and who have been charged for allegedly abducting Maria and document fraud.

A lawyer representing the Greek couple said Friday they planned to seek legal custody of the fair-haired girl.

The couple have told authorities they had received Maria after an informal adoption.

Under Greek law, child abduction charges can include cases where a minor is voluntarily given away by its parents outside the legal adoption process.

"Now that they're in prison there's not much they can do," their lawyer, Costas Katsavos, said.

"But provided what we said is borne out, that it was not an abduction, then logically they will be released from prison and they will be able to enter a proper (adoption) process ... They truly and ardently want her back."

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"Maria" DNA matches couple in Bulgaria

New research suggests thatso-called junk DNA might not be so worthless after all. It might actually help us tell each other apart.

Face shape is largely determined by genetics, yet no two faces are entirely alike. How do genes bring about faces with subtle differences while avoiding dramatic disruptions and facial malformations such as cleft lip and palate? The answer may be in the "junk DNA," a new study has found.

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NoncodingDNA, sometimes called junk DNA, refers to sequences in a genome that don't produce proteins, some of which are thought to have no known biological function.

Studying mice, researchers identified more than 4,000 small regions in the genome that are likely a type of noncoding DNA called enhancers, which amplify the expression of a gene. In this case, these regions were active while the face of a mouse embryo developed, according to the study, detailed in the Oct. 25 issue of the journal Science.

Most of these enhancer sequences are found in humans as well, so it is likely that they have similar face-shaping functions in humans, the researchers said. [5Face-Shaping Genes Identified]

"Our results suggest it is likely there are thousands of enhancers in the human genome that are somehow involved in craniofacial development," study researcher Axel Visel, a geneticist at Lawrence Berkeley National Laboratory's genomics division, said in a statement. "We don't know yet what all of these enhancers do, but we do know that they are out there and they are important for craniofacial development."

To test whether these enhancers are indeed important inshaping the face, the researchers deleted three of the enhancers in mice and compared them with normal mice at 8 weeks of age. The results showed that each enhancer deletion caused a distinct set of differences in the shape of the face for instance, causing an increase or decrease in facial length and an increase or decrease in the width of various parts of the face, such as the base of the skull or the palate.

In the study, to avoid the challenge ofrecognizing individual mouse faces, the researchers created 3D images using a process called microcomputed tomography to link changes in face shape with alterations in the function of each of the enhancers.

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'Junk' DNA could determine face shape, scientists say

NIKOLAEVO, Bulgaria DNA tests have confirmed that a Bulgarian Roma couple are the parents of a mysterious girl in Greece known as Maria, authorities said Friday.

Genetic profiles of Sasha Ruseva and her husband, Atanas, matched that of the girl, said Svetlozar Lazarov, an Interior Ministry official.

Ruseva has said she gave birth to a baby girl four years ago in Greece while working as an olive picker, and gave the child away because she was too poor to care for her.

12 Photos

Maria has been placed in temporary care since last week after authorities raided a Roma settlement in central Greece and later discovered that girl was not the child of a Greek Roma couple she was living with. The couple has been arrested, and who have been charged for allegedly abducting Maria and document fraud.

A lawyer representing the Greek couple said Friday they planned to seek legal custody of the fair-haired girl.

The couple have told authorities they had received Maria after an informal adoption.

Under Greek law, child abduction charges can include cases where a minor is voluntarily given away by its parents outside the legal adoption process.

"Now that they're in prison there's not much they can do," their lawyer, Costas Katsavos, said.

"But provided what we said is borne out, that it was not an abduction, then logically they will be released from prison and they will be able to enter a proper (adoption) process ... They truly and ardently want her back."

Continued here:
DNA test shows Bulgarian Roma woman is mother of "Maria"

LONDON -- DNA tests have confirmed that a Bulgarian Roma couple are the parents of Maria, a blond, green-eyed 4-year-old girl taken by police in central Greece last week from the Roma settlement where she was living, Bulgarian authorities said Friday.

Authorities undertaking a drug raid had arrested a Greek Roma couple, Crhostos Salis, 39, and Eleftheria Dimopoulou, 40, suspecting Maria had been abducted. The couple, still jailed, said they had informally adopted her from her Bulgarian Roma parents.

The Bulgarian government said the scientific tests showed that Bulgarian Roma Sasha Ruseva, a 34-year-old mother of eight, was the child's mother. Ruseva said she gave birth to a baby girl in Greece in 2009, when she worked there as an olive picker, but knew she could not afford to care for another child and voluntarily handed her over for adoption.

She said that after seeing Marias photo, she was convinced the child was hers although she could not be sure without the DNA test.

Greek authorities search for the girls parents through widely published photos of her on posters and websites triggered a worldwide response.

Sightings of other children living in Roma communities and whose light-skinned appearance does not match those of their families have sparked widespread controversy as police suspicions of child trafficking clash with accusations of racism.

In two widely reported recent cases in Ireland, children were also seized by police who suspected they were not the natural offspring of their Roma parents. In both cases, police were proved wrong by DNA tests and the children were returned to their families.

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DNA tests show blond girl seized by police is daughter of Roma mother