Dna

The coiled molecules of DNA in human cells carry a unique chemical code that can match a trace of blood, semen, skin or hair to the person who left it. DNA (deoxyribonucleic acid) carries its code in four characters denoted by the letters A,T, C, and G. But no microscope is powerful enough to see how this code is arranged on a given DNA molecule, so science must use more indirect methods to read it. Forensics laboratories use several different methods for determining whether two samples indeed carry identical stretches of code.

They seemed unlikely candidates to make one of the pivotal discoveries of the 20th century. Francis H.C. Crick was a 35-year-old Ph.D. candidate who had abandoned physics, hoping to find his niche in biology. James D. Watson was a gawky-looking 24-year-old who rarely bothered to tie his shoelaces. Both scientists were supposed to be working on other things, but they believed fervently that the most important scientific problem of their time was the mystery of inheritance - how everything from diseases to hair color to the very instructions to make a human being was passed on from generation to generation.

A man arrested recently in Puerto Rico for domestic offenses resembles the composite of the Fairmount Park rapist, city police said yesterday, adding that the suspect has lived in Philadelphia. As a result, the man, whose name was not released, has agreed to provide DNA that will be compared with evidence collected in the murder and rape of medical student Rebecca Park in Fairmount Park and the rape of another woman off Kelly Drive. The Fairmount Park assailant is also suspected of a third attack on the West River Drive in which the victim managed to fight off her attacker.

Do you have the feeling you're related to someone famous? Maybe it's an uncanny sense that Mozart was your ancestor. Or that Genghis Khan might be in your family tree. That affinity you feel for ancient Rome can't be an accident, can it? Touring the toppled ruins of columns and friezes in the ancient city stirs something in you. Perhaps one or your ancestors was one of those emperors, or perhaps just a Roman soldier. It's in your blood. Now, with a simple swab of your cheek and a few hundred dollars, you can find out. Commercial genetic genealogy is barely five years old, but already it is proving irresistible to many.

One recurring theme in reader questions, especially from creationists, is that Darwinian evolution can't explain big changes - the invention of fur or feathers, kidneys or brains. These readers don't see how such innovation could possibly come about through random spelling errors in DNA, no matter how many millions of years they had to accumulate. ". . . the concept of 'descent with modification' cannot generate more complex systems . . . the old adage that if you give 1,000 monkeys 1,000 years to randomly type we could get the works of Shakespeare is false.

POLICE yesterday announced the arrest of a man who allegedly raped a 40-year-old woman outside the Linc during an Oct. 5, 2008, Eagles-Redskins game. "It was obviously a real challenge for us because of the number of people in and around that stadium," Special Victims Unit Capt. John Darby said yesterday. "It's almost like finding a needle in a haystack. " Police said they arrested Tiaghgee Daughtry, 22, who lives in Tunkhannock, Pa., near Scranton, on Wednesday, for allegedly raping the woman on a bus during the game.

No one really knows what happened to Phil Purcell's plane that day in September 1963 over Kontum, Vietnam. A relief pilot saw him turn his ancient B-26 back toward Da Nang. But he never arrived - plunging, instead, into the highlands below and vanishing beneath the oncoming tide of history. For three decades, as his bones and those of his crewmates moldered in Vietnam, as his children grew up and his wife remarried, the story of who he was lay locked in his body's DNA, like a song waiting to be heard.

Why do visions of war and hacked, stub-limbed civilians from Africa fail to move us as much as the images of civilians under attack in other parts of the world? I contend that we - whites, blacks and blends - are less moved by images from Africa because we've lost the emotional connection with the branch of the African human family tree. Geneticists recently have published results that say we all share the same DNA with slight variations based on traumas and the places we've passed through, via our ancestors.

For 41 years, the boy in the box has rested in his pauper's grave - unidentified, his murder unsolved. Yesterday, in a final attempt to find his killer, police removed him from his solitary grave in a potter's field in Northeast Philadelphia. They took his body to the medical examiner's office, where technicians will try to extract DNA from his remains. They hope such evidence will help identify him and eventually help nail his killer. "It's hard but it's been done before," said Lt. Ken Coluzzi, head of the special investigations unit at the police Homicide Division.

A man who was already in prison for a sex crime was charged Wednesday with another sexual assault, police said yesterday. Franklin Evans, 34, is serving 15 to 40 years in Graterford Prison after being convicted of charges of involuntary deviate sexual intercourse, aggravated indecent assault and unlawful contact with a minor stemming from an incident in 1999, according to court records. Evans was arrested in that case in 2007 and was sentenced in May of this year, court records show.

ISLAMABAD, Pakistan - The Pakistani doctor who helped the CIA hunt for Osama bin Laden was sentenced Wednesday to 33 years in prison for treason in an administrative action under colonial-era laws that avoided a public trial. The move brought condemnation in Washington, where officials had been hoping to win freedom for Shakil Afridi, whom Pakistani intelligence agents detained three weeks after the May 2, 2011, U.S. special forces raid in the northern town of Abbottabad that ended in bin Laden's death.

THE WOMAN'S 5-foot-3, 100-pound nude body, beaten and bruised, with her bra strap tightly wrapped around her neck, was found behind her 4th Street building in a lot strewn with rubble and dog waste, a city prosecutor said Tuesday. "Tiny, small, petite but so vulnerable. Perfect prey," Assistant District Attorney Richard Sax said of Sabina Rose O'Donnell during his opening statement. Sax told the jurors that Donte Johnson — the 20-year-old high-school dropout accused of abducting, raping and murdering the popular Northern Liberties waitress — stalked O'Donnell along Girard Avenue, as she rode a borrowed bicycle home in the early morning of June 2, 2010, because "he knew he could dominate, overwhelm and control" her. But as Johnson rode his own bicycle behind hers, Sax said, he was recorded on store video cameras, which the jury will be shown.

The confession that an 18-year-old Donte Johnson made to police in June 2010, in which he described the rape and killing of Sabina Rose O'Donnell, can be used as evidence in Johnson's trial this week, a judge ruled Monday. Johnson's attorneys fought to keep the statement out of the trial, arguing that Johnson, now 20, functions at the cognitive level of an 11- or 12-year-old and could not have understood his rights when he confessed. "The detective speaks to Mr. Johnson and he thinks he's talking to an adult, when in reality he's speaking to a child," said attorney Gary Server.

Blurring the lines between life and inanimate matter, biologists announced Friday that they'd created six different chemical alternatives to DNA and coaxed them to undergo evolution. A description of these code-carrying molecules, called XNAs, was published in the journal Science. The work bolsters a prevailing hypothesis that life as we know it evolved from simpler life forms, no longer here, and those evolved from something simpler. There may be no moment when the first life emerged, but instead an evolutionary process by which chemicals that most of us would consider non-life gradually gave rise to living cells through natural selection.

Philadelphia Police have arrested Robert Leo Ashley, of 1300 block South Divinity Street, for the September 2011 rape of an 81-year-old Southwest Philadelphia woman as she slept in her home. Ashley, 59, broke into the woman's home on S. 51st Street and ransacked the bedroom before assaulting the woman, police said. The woman, who lived near Ashley, was taken to Thomas Jefferson University Hospital where she was treated for her injuries. The evidence gathered by authorities resulted in a positive DNA match for Ashley, police said.

WILLIAM F. Buckley, a man who made love to the English language, would have raised his patrician eyebrows at people who call mandatory transvaginal ultrasounds "rape. " It's not that I think he'd agree with laws that force women to undergo the procedure. No, it's the deliberate manipulation/mutilation of words for partisan purposes that would have disturbed the Great Right Hope. "Rape" conjures up images of violence, blood, bruising and shattered lives, (or, for that matter, frat boys about as drunk as their passed-out "dates")

LOS ANGELES - A jury yesterday found former Los Angeles Police Detective Stephanie Lazarus guilty of murdering the wife of a man she loved, bringing an end to a remarkable case in which a new generation of the LAPD redeemed the failures of a past one. After 1 1/2 days of deliberation, the panel of eight women and four men delivered its decision in a cramped downtown courtroom filled with the victim's family members, relatives of Lazarus, and...

AWITNESS who was testifying for the prosecution yesterday about a June double murder in North Philadelphia leaned forward in his seat so far that his face was hidden under the witness stand - just the way he wanted it. "What did you see?" Assistant District Attorney Brendan O'Malley asked the man, whose name the Daily News is withholding. "What I didn't want to see," the man said, referring to the afternoon slayings. "Are you scared?" O'Malley asked at one point during the preliminary hearing.

LiftDNA Inc., a 29-month-old online-advertising technology firm in King of Prussia, has been purchased by OpenX Technologies Inc. of Los Angeles. Terms of the transaction between the two privately held companies were not disclosed. Launched in September 2009, LiftDNA helps Web-based publishers maximize revenue from their online-advertising inventory - the display-advertising opportunities that have not been sold by a direct-sales force. LiftDNA was started by Kingchih Fan and Vadim Telyatnikov, who was one of the first dozen employees of New Hope-based myYearbook.com, a social-media site focused on teenagers.