Category Archives: Transhuman News

PUBLIC RELEASE DATE:

9-Sep-2014

Contact: Peter Iglinski peter.iglinski@rochester.edu 585-273-4726 University of Rochester http://www.twitter.com/UofR

As we and other vertebrates age, our DNA accumulates mutations and becomes rearranged, which may result in a variety of age-related illnesses, including cancers. Biologists Vera Gorbunova and Andei Seluanov have now discovered one reason for the increasing DNA damage: the primary repair process begins to fail with increasing age and is replaced by one that is less accurate.

The findings have been published in the journal PLOS Genetics.

"Scientists have had limited tools to accurately study how DNA repair changes with age," said Gorbunova. "We are now able to measure the efficiency with which cells in mice of different ages repair DNA breaks at the same place in the chromosome."

Gorbunova explained that when mice are young, the breaks in DNA strands are repaired through a process called non-homologous end joining (NHEJ), in which the damage is repaired by gluing the DNA together with no or very little overlap. However, Gorbunova and Seluanov found that NHEJ began to fail as the mice got older, allowing a less reliable DNA repair processmicrohomology-mediated end joining (MMEJ)to take over. With MMEJ repairs, broken ends are glued together by overlapping similar sequences that are found within the broken DNA ends. This process leads to loss of DNA segments and the wrong pieces being stitched together.

Gorbunova and her team were able to make their observations by working with genetically-modified mice whose cells produce green fluorescent protein (GFP) that glows each time the breaks are repaired. By tracking how many cells glowed green in different tissues, the researchers determined the efficiency of repair.

"We showed two things with these genetically-modified mice," said Gorbunova. "Not only did the efficiency of DNA repair decline with age, but the mice began using a sloppier repair mechanism, leading to more mutations, particularly in the heart and lungs."

DNA breaks occur frequently because animal cells are under constant assault from routine activities in the environmentwhether by a blast of X-rays from a visit to the doctor or simply breathing in oxygenand, as a result, the DNA molecules often get damaged.

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Less effective DNA repair process takes over as mice age

In the end, it may have takena Johnny Depp movie, a shawl and a DNA testto solvethe mystery behind one of the most notorious serial killing sprees in London: Who was Jack the Ripper?

British businessman and noted "Ripperologist" Russell Edwards claims to havefinally and conclusively identified the serial killer asAaronKosminski, a Polish immigrant and barber.

Edwards unmasked his candidate for Jack the Ripper in the Daily Mail and chronicles how he came to the conclusion in a forthcoming book.

Kosminski has long been one of the more credible suspectsin thefivegruesome murders of women in the London's East End in 1888. Born in central Poland on Sept. 11, 1865, he moved with his family movedto east London in the early 1880s, and lived near the murder scenes, according to Agence France Presse.

He ended up in a workhouse the year after the murders and was described as destitute; a year later, he was discharged but eventually ended up in an insane asylum -- he was thought to have been "seriously mentally ill," Edwards writes -- where he died from gangrene in 1919. A witness had identified Kosminski as the murderer at the time.

Edwards said his interest in Jack the Ripper began after he watched"From Hell," a2001 film about the murders that starred Depp as a clairvoyant police inspector.

In 2007, Edwards bought a shawl thathad been discovered at the scene of the murder of Catherine Eddowes, the fourth Ripper victim. Before Edwards bought it, the shawl belonged to the relative of a police official who had been allowed to take it home to his dressmaker wife, Edwards writes. "Incredibly, it was stowed without ever being washed," and handed down in the family, he said.

When Edwards bought the shawl, he subjected it to DNA testing, which confirmed that the blood on it belonged to Eddowes. A UV light showed semen on the fabric. That DNA was compared to that of a Kosminski descendant, Edwards writes.

The identity of Jack the Ripper haseluded Brits for over a century and obsessedeveryone from serious academics to armchair detectives. Queen Victoria's grandson Prince Albert Victor was thought to be a suspectat one point, but it turned out he wasn't near the murders at the time. Other suspects have includedMary Pearcey ("Jill the Ripper"), who had been convicted of murdering her lover's wife; in 2006, an Australian scientist, pointing to DNA results, suggested the killer may have been a woman.

Historian Mei Trow had previously identified mortuary attendant Robert Mann as Jack the Ripper, using "psychological and geographical profiling," the Daily Mail wrote in 2009.The murdervictims' bodies would have been delivered to the mortuary where Mann worked, where he was suspected to have "admire[d] his handiwork."

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WorldViews: Author claims to have identified Jack the Ripper via DNA testing of a shawl