Home DNA Testing

Home DNA Testing

News and insights in the world of DNA and genetics for paternity, immigration and forensics

Archive for April, 2010 Monthly Archives

A new study failed to provide answers after pursuing a genetic explanation for why one identical twin developed multiple sclerosis while the other stayed healthy.  Researchers created complete genetic blueprints for a pair of  identical twins, looking for differences that might explain why one developed multiple sclerosis and the other did not. According to researchers there were no traces of a discrepancy in the twins’ DNA.  Scientists found no smoking gun when they compared amount of gene activity between the twin with multiple sclerosis and the twin without. The results appear in a study published on April 29 in Nature.

According to Stephen Kingsmore, a geneticist at the National Center for Genome Resources in Santa Fe, N.M., and leader of the new study, “We looked under a lot of rocks and we found no differences that we could replicate.” Kingsmore went on to say that the findings “points to some novel environmental trigger that must be very important to the disease. We don’t know what it is.”

This study was small; it examines only three pairs of identical twins and  one type of immune cell known to be involved in multiple sclerosis. A telling difference between sickness and health might be found in other types of cells, says Esteban Ballestar of the Bellvitge Biomedical Research Institute in Barcelona, Spain.  Ballestar went on to say, “They are closing a door here, but I think, perhaps, the door should be open.” Multiple sclerosis is a disease where the immune system attacks and damages the myelin sheath that helps speed electrical communication between nerves, this is the equivalent of scraping the coating away from an electrical wire. The damage results in pain and symptoms such as loss of coordination and vision.

In the study, Kingsmore and his colleagues determined the entire genetic makeup of the immune cells called T cells from the female twin who had developed multiple sclerosis at age 30 and from her twin who had remained healthy. It was important that the twins were now old enough that the healthy one is not likely to develop the disease.

Identical twins share the same genetic makeup (it is believed that they have identical DNA), and the researchers confirmed that both women carried variants of genes already known to increase the risk of getting multiple sclerosis. Scientists had thought that maybe the sick twin had developed an additional mutation in her DNA that finally triggered the disease. But the team found no such mutations.

With the stroke of Gov. Ted Strickland’s pen on April 6, 2010, experts say Ohio now has some of the best laws in the country to protect the innocent from wrongful convictions and put the right people behind bars.

Strickland, joined by a handful of men who were exonerated after serving years in prison for crimes they did not commit, signed Senate Bill 77. It sets statewide standards for retaining biological evidence, requires the taking of DNA from anyone arrested on a felony charge and requires new procedures for suspect lineups.

Goodman introduced the bill after a Dispatch investigation in January 2008 exposed widespread shortcomings in Ohio’s DNA law, including the derailing of prisoner DNA tests by systemic indifference or hostility.

In addition to requiring that DNA samples be taken from anyone convicted of a felony after July 1, 2011, the new law:

•Requires law-enforcement agencies to retain biological evidence for up to 30 years in murder and sexual-assault cases. The limit is five years when a defendant pleads guilty.

•Opens DNA testing to parolees and those on the sex-offender registry.

• Mandates blind suspect lineups, in which the officer presiding either does not know the identity of the true suspect or uses a photo-lineup technique in which only the witness can see pictures placed in folders.

•Gives an incentive for law-enforcement officials to record interrogations.
(excerpted from Jim Siegel of THE COLUMBUS DISPATCH)

Norh Robinson  84-year-old World War II veteran and a Mississippi farmer now living in a rural VA hospital, wants Oprah to participate in a paternity test that he says would once and for all prove that he is her father.  During a at his hospital, Robinson said that he met Oprah’s mom when they worked in the same part of Kosciusko and that he often drove her to and from work.

Robinson says that he has no interest in her money but that he would like to speak with Oprah as father and daughter before he dies.  Robinson claims that years ago, he tried to reach the talk-show queen to asked her to agree to a DNA test.  In an interview with The Post Robinson said, “I told her [in a letter], if she wanted, I’d give her one.”

In the letter, he placed mementos from his life, including his Social Security number and a picture of him from the Navy in World War II, he said.  “I never got no answer, I never did get no answer. If I did, it didn’t get to me, I’d like her to call me,” said the Wold War II Vet.

Oprah was raised by her mother, Vernita Lee, 75, and Lee’s longtime boyfriend, Vernon Winfrey. Oprah considers Vernon her father but has figured out he isn’t her biological dad.

When confronted on April 19th about the story, Oprah Winfrey was very upset when asked if she would undergo DNA testing to learn the identity of her biological father.  Oprah stated, “I will not be taking a paternity test, ever! I’ve never heard of him. I know who is claiming to be my real father.”

When Winfrey was asked what Robinson could possibly gain by lying about her lineage her only response was, “Get out of my face!” before pushing the Post reporter aside to jump into an SUV and head for lunch.

Read More

By Alex Blake

DNA testing is done for many different reasons.  Sometimes DNA evidence can link an alleged criminal to a crime scene or DNA paternity and maternity testing can identify a child’s father or mother. While DNA relationship testing can determine if two individuals are full or half siblings and DNA ancestry testing can determine ethnic origins and genealogical roots.

How DNA testing is done depends on the results desired and the samples available. DNA profiling is the process of analyzing and comparing two DNA samples. Only identical twins have the exact same DNA sequence, everyone else’s DNA is unique. This makes DNA the perfect way to link individuals to each other or to locations where they have been.

The entire DNA chain is incredibly long, much to long to examine all of it. Human DNA is made up of about 3.3 billion base pairs. The differences between DNA samples occur only in small segments of the DNA–the rest of the DNA is very similar. DNA testing focuses on those segments that are known to differ from person to person.

As DNA testing has evolved over time, the testing methods have become more precise and are able to work with much smaller DNA samples. Early DNA testing was done using dime-size drops of blood. Today’s tests can extract DNA from the back of a licked stamp (in some cases) but is most often done by using cheek swabs.  These cheek swabs are easy to collect, painless and very accurate The DNA must be extracted from whatever sample is provided. DNA must be isolated and purified before it can be compared. In essence, it has to be “unlocked” from the cell in which it exists. The cell walls are usually dissolved with a detergent. Proteins in the cell are digested by enzymes. After this process, the DNA is purified, concentrated, and tested.

DNA testing is done most often today using a process called “short tandem repeats,” or STR. Human DNA has several regions of repeated sequences. These regions are found in the same place on the DNA chain, but the repeated sequences are different for each individual. The “short” tandem repeats (repeated sequences of two to five base pairs in length) have been proven to provide excellent DNA profiling results. STR is highly accurate–the chance of misidentification being one in several billion.

I just came across an article distributed by the Slate discussing the above topic. This brought my thinking to the use of DNA and the idea of anonymity in general.

DNA testing makes them easy to trace
By Rachel Lehmann-Haupt Last Updated Monday, March 1, 2010, at 9:36 AM ET

When Donor 3066 signed up with the California Cryobank, he offered some basic information about himself on a piece of paper: that he had a BA in theater; that his mother was a nurse and his father was in the Baseball Hall of Fame; that his birthday was Sept. 18, 1968. He made it clear that he didn’t want to be found by signing a waiver of anonymity…

Donor 3066 was being sought out by Michelle Jorgenson, a 39-year-old waitress from Sacramento, Calif., whose daughter, Cheyenne, was born in 1998.  When her daughter turned 5, Jorgenson joined the Donor Sibling Registry and began searching for other mothers and donor offspring who used Donor 3066. She was concerned because her daughter was sensitive to sounds and walked on her toes, and she wanted to know if other half-siblings were displaying similar behavior. Through the registry, she met a number of other mothers and half-siblings. She discovered that two had autism and two others showed similar signs of sensory disorder…

Jorgenson began her search by approaching a mother in her group with a son named Joshua and suggested he do a cheek swab so she could explore his paternal roots through a Y chromosome test. The mother agreed. Through the test, Michelle learned about some of Joshua’s genetic markers. A few weeks of searching on the Family Tree DNA Web site using these markers led to two families with matching DNA. Through one of the families, she met a woman who mentioned that she found the obit of a relative who was a former baseball manager, and three children were listed. Michelle suspected that this might be her donor’s father, so she looked up the phone number of his listed son. When Michelle called the number, the deceased man’s son answered the phone. She began to ask him questions: Was your father in the Baseball Hall of Fame? Were you born in Illinois? Did you ever donate sperm? When the man said yes, she asked him if his birthday was Sept. 18, 1968. When he answered yes, she burst into tears. “You’re the biological father of my daughter,” she said. He was shocked but agreed to talk to Cheyenne on the phone—and eventually allowed the two to come visit him in Los Angeles.

Although in this case there appears to be a happy out come for all parties this is not always the case.  What about the request for privacy that Donor’s sign up for when they choose to remain anonymous?  Is that even something that clinic should offer since there is no guarantee that the donor can’t be found?  What are the options for men who do become donors?  There are many questions that are raised in this article and very few answers, partly because technology is growing at such a fast rate and party because it appears in the article many clinics are ignoring this issue of privacy.  Let us know what you think about this issue.