Deciphering Daddy's DNA

FYI

Deciphering Daddy's DNA By Nancy Shute Mon Mar 5


Not so very long ago, fatherhood had a bit of mystery to it. No more.
Advances in genetics have made paternity tests one of the simplest
and
most reliable medical tests ever available. Being able to be 99.99
percent sure has helped fuel the frenzy over the fate of little
Dannielynn, the late Anna Nicole Smith's infant daughter, and her
four
would-be daddies. It also made last week's announcement that DNA
samples would be taken from the body of the late soul legend James
Brown before burial-to settle new paternity claims-seem almost
commonplace.


Far from Hollywood, DNA-based paternity tests are used every day to
determine child support and custody or to put a worried mind at ease.
"It was a relief," says Mandy, 32, of Kansas, who asked that her last
name not be used. Her father had died at age 16 and hadn't told his
parents he'd gotten a girl pregnant. A few months ago, Mandy decided
she wanted a family medical history for her children, ages 8 and 11.
She asked her father's parents, and they said they'd like to do DNA
testing first. Last week, she found out that they are indeed her
grandparents. "I was scared to death that maybe my mom wasn't honest
with me," she says. "It's neat having the confirmation that
everything
I had been told was in fact the situation."


As DNA technology has become more precise, paternity tests like
Mandy's, which could be done without her father's DNA, are becoming
cheaper and easier. It's now possible to determine paternity using
DNA
from cousins or grandparents, or from a discarded coffee cup.
Procedures such as amniocentesis can be used to determine paternity
well before a baby's birth. And sometime soon, noninvasive tests may
be able to ID Dad through bits of fetal DNA floating in a pregnant
woman's blood.


Paternity testing first hit the headlines in 1943 when starlet Joan
Berry sued Charlie Chaplin, claiming he was the father of her child.
A
simple blood-type test proved Chaplin could not be the father, but at
the time such tests weren't admissible in court, and Chaplin was
ordered to pay child support. The case prompted new laws allowing
blood tests in paternity cases, but those tests could eliminate just
40 percent of males as the father. In the 1970s, new tests based on
variations in white blood cells raised the exclusion rate to 80
percent. DNA testing, which entered the market in the late 1980s, has
made paternity testing almost foolproof, raising the accuracy rate to
99.99 percent for the most common tests. Further testing can raise
the
odds to astronomical levels in contested cases. "The accuracy has
greatly increased," says David Gjertson, a professor of biostatistics
at the University of California-Los Angeles who helped develop DNA-
based paternity tests.


Then there's the CSI approach. Current DNA tests make it possible to
use old or degraded DNA samples, such as random cells from a man's
razor or even from earwax on a used Q-Tip. Sometimes dental floss
tells the tale. In 2002, millionaire Steve Bing alleged that MGM
mogul
Kirk Kerkorian, then 84, had hired private investigators to go
through
the trash can outside Bing's home. Bing had been romantically linked
with Kerkorian's ex-wife, Lisa Bonder Kerkorian. DNA on dental floss
fingered Bing as 4-year-old Kira's father. "You can send us almost
anything, and we can get DNA out of it," says Howard Coleman, CEO of
Genelex, a genetics-testing lab in Seattle. "Anything that someone's
had contact with ... and we can give you a very conclusive answer."


The simplicity of gathering DNA, and the public's growing knowledge
that every used soda can tells a story, has increased the opportunity
for fraud in paternity cases. Kerkorian's former wife admitted using
saliva from one of his grown daughters in an attempt to prove that
Kerkorian was Kira's father. State child-support programs, which pay
for the bulk of paternity testing, require that the parties being
tested appear in person at a designated site in order to establish a
"chain of custody."


Chain of custody is also crucial in immigration cases. Increasingly,
United States embassies require paternity testing to verify the
relationships of people seeking to join family members in the United
States. Terry Carmichael, vice president of marketing and sales at
Gene Tree in Salt Lake City, says 5 percent of the lab's paternity
work involves immigration. Labs that are certified by the
international blood bank association AABB follow standards to assure
a
chain of custody. Still, fraud happens. Men will send a buddy in to
give a sample, or a woman will bring in a different child.


Know now. Traditionally, children aren't tested to determine
parentage
until they are born. But some parents aren't willing to wait.
Chorionic villi sampling and amniocentesis, which are used to test
fetal DNA for genetic disorders such as Down syndrome, can also be
used to identify the baby's father in the first or second trimester.
Dawn, who asked that her last name not be used, found herself
shopping
for prenatal paternity testing after she went through a rough patch
in
her life, had a one-night stand, and then found out she was pregnant.
"My husband was worried that it wasn't his," she says. "I knew it was
my husband's baby, but he wanted to be 100 percent sure that it was
his, so he could be excited through the pregnancy." The couple found
Gene Tree on the Internet, and paid $445 for the test. Dawn's
obstetrician agreed to do an amniocentesis, and the sample was
compared with those from Dawn and her husband. The baby, to be born
this summer, is his. "It would be nicer if it wasn't so expensive,"
says Dawn, 27, "but it meant more to us to relieve that anxiety and
worry."


In 1997, researchers in Hong Kong discovered that bits of DNA from a
fetus float freely in the mother's blood throughout pregnancy. Since
then, scientists have been hard at work trying to figure out how to
use that DNA to devise better tests for genetic disorders like Down
syndrome. But companies like Gene Tree are already marketing baby-
gender tests based on free fetal DNA, and Carmichael predicts that
paternity tests are 18 months away. "It's annoying," Farideh
Bischoff,
a molecular cytogeneticist and associate professor at Baylor College
of Medicine, says of these souped-up versions of "Who's Your Daddy?"
that are coming ahead of broader medical applications, the kind she's
working to develop.


But people have a way of using science to find out what they really
want to know, and Carmichael has no doubt that there will be a market
for these paternity tests, too. "We know the answer to the question
is
very, very important," he says. "We think it will reduce people's
anxiety and prepare them for fatherhood."