Non-invasive approach to obtaining fetal genome developed in lab

Scientists from the University of Washington have made laboratory news by developing a non-invasive approach to obtaining fetal genome.

Jacob Kitzman and Matthew Snyder, working in the laboratory of Dr. Jay Shendure at the University of Washington have successfully sequenced the genome of a baby in the womb without tapping its protective fluid sac. They obtained maternal blood around 18 weeks into the pregnancy and a paternal saliva specimen which allowed them to map the fetus' DNA, with checks on the accuracy of the technique being conducted using umbilical cord blood collected at birth.

Scientists have been interested in a pregnant woman's blood plasma for some time, with studies confirming that it contains cell-free DNA from her developing fetus. There is other laboratory research being conducted to develop maternal blood tests for major aberrations in the fetus's genetic makeup, which are considered a safer substitute for the more invasive sampling of fluid from the uterus.

The tests can search for genetic disorders or specific congenital abnormalities, such as a test targeted for Down syndrome would look for evidence of three copies of chromosome 21. The new development by Mr Kitzman and his team give scientists the ability to assess many and more subtle variations in the fetus' genome, down to a minute, one-letter change in the DNA code.

He explained: "The improved resolution is like going from being able to see that two books are stuck together to being able to notice one word misspelled on a page."

The researchers were able to overcome previous obstacles to determine fetal genomes by using new technical advances and statistical modelling. They also made use of a new technique to resolve the mother's haplotypes, which allowed them to pick out the parts of the baby's genetic material inherited from each parent with over 98 per cent accuracy.

Posted by Fiona Griffiths