April 25, 2002 |
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.
July 3, 2000 |
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.
June 3, 2004 |
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.
October 12, 2006 |
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.
June 16, 2013 |
In a narrow ruling June 3, the U.S. Supreme Court declared that the DNA swabbing of people arrested in connection with serious crimes is legal. The Maryland attorney general praised DNA swabbing as the 21st-century equivalent of fingerprinting and said it would help solve crimes. No doubt. But the ruling represents yet another way our DNA is slipping beyond our control even as few standards exist for its use, storage, and destruction. The implications are laid out in Biotechnology in Our Lives , the latest book from the Council for Responsible Genetics, a Cambridge, Mass., nonprofit focused on the ethics of gene research and biotechnology.
July 7, 2014 |
It's become the last, best hope of people charged with a crime: a DNA test that proves police have the wrong guy. Tell that to Antwon Watkins. The 16-year-old South Philadelphia High School junior was found guilty of simple assault by a Philadelphia Family Court judge April 28 despite negative DNA results, alibi witnesses, school attendance records, and having no prior arrests. It could have been worse. Watkins had been charged with aggravated assault on a police officer.
May 19, 2014 |
Imagine a document 25,000 words long - about 100 pages, double-spaced - with one small error. Within the text of our genetic code, a single change like this can lead to a life-threatening disease such as sickle-cell anemia or cystic fibrosis. Most of these single-gene disorders have no cure. But using a new technique, doctors may one day be able to correct the genetic typo by replacing a harmful mutation in the genome with healthy DNA. Introducing CRISPR (clustered regularly interspaced short palindromic repeats)
November 4, 2011 |
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.
December 26, 1996 |
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.
June 4, 2000 |
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.