WEDNESDAY, June 6 (HealthDay News) -- Researchers report they have decoded the entire genome of a fetus using only a blood sample from the mother and a saliva sample from the father.
The scientists said prenatal genome sequencing using the noninvasive method could one day be used to determine if a fetus has any of the thousands of genetic disorders that are caused by a single, often devastating, mutation on one gene.
In pregnant women, bits of fetal DNA move through the mother's body in the plasma, a component of blood. Unlike a sample of DNA taken directly from fetal tissue or from amniotic fluid -- such as when expectant mothers undergo amniocentesis to look for chromosomal disorders such as Down syndrome -- the DNA in plasma is in fragments.
That makes analyzing it complex, but increasingly possible given the latest generation of gene-sequencing technology, explained study author Jay Shendure, an associate professor of genome sciences at the University of Washington.
"The chromosomes are shattered, but all the information is there, represented in small fragments," Shendure said.
In the current study, researchers used plasma from a woman who was 18 weeks pregnant and saliva from the dad to tease out which was fetal DNA. Researchers confirmed the accuracy of their conclusions by mapping the baby's DNA using umbilical cord blood after birth.
Testing for genetic problems using a blood sample and saliva would be an improvement over more-invasive tests such as amniocentesis, which can pose risks to the fetus, Shendure said.
"This fits in quite well with what we do today, which is to provide expectant mothers with as much information as we can," Shendure said. "It would simply be more comprehensive."
Still, he noted, the paper should be viewed as a "proof of concept," or showing that noninvasive whole fetal genome sequencing was possible. More
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