REPORT #5: 2ND EMERGING TECH ASSESSMENT
PRENATAL DNA SEQUENCING
Student: Quynh Nguyen
Technology definition:
Prenatal DNA sequencing is sequencing the DNA of a fetus from a pregnant woman’s blood
(Regalado, 2013). This technology helps parents to find out what medical condition their child
will be in. It helps to discover what problems or disorders the baby will have so they will be able
to set up help for them in advance.
Technology explanation:
Prenatal DNA sequencing technology provides noninvasive prenatal screening for pregnant
women. First, noninvasive prenatal sequencing involves a simple blood test from the mother,
so it is safe and pose minimal risk to mother or baby. The tests can be conducted starting from
10 weeks of gestation. Then prenatal DNA sequencing technology sequences the bits of DNA
floating in a sample of the mother’s blood. Around 12% of the DNA in a mother’s bloods
belongs to her fetus. The test does not distinguish which sequences belong to mom or the
unborn baby. It uses counting algorithms to search for small but significant changes in the
amount of one chromosome to another. DNA sequencing machine reads out strings of DNA
letters a few dozen base pairs long, then it sorts the mix of mom’s and baby’s sequences by
chromosome. If there are more sequences than expected belonging to a particular
chromosome, then the fetus probably carries an extra copy (Rojahn, 2013).
For example, to detect Down syndrome, which occurs when an individual has a full or partial
extra copy of chromosome 21, the test randomly sequences millions of circulating DNA
fragments, often only 50 to 500 DNA letters long. Using a computer program, the sequences
are lined up against a map of human chromosomes. After that, it’s a counting exercise, if more
bits than expected match up with chromosome 21, that’s evidence of an extra copy somewhere,
ant the fetus probably has Down syndrome (Regalado, 2013).
Timeline of Events: History of DNA sequencing technologies

1953: James Watson and Francis Crick discovered the DNA double helix structure.

1977: One of the first DNA sequencing methods was developed by Frederick Sanger.
Sanger's technique became the basis for modern innovations.

1986: Applied Biosystems marketed the first automated DNA sequencing.

1997: a Hong Kong scientist named Dennis Lo showed that a pregnant woman’s blood
contains trillions of bits of DNA from her baby.

2004: 454 Life Sciences markets a version of Pyrosequencing, the second of a new
generation of sequencing technologies.

2006: Illumina next generation sequencing is on the market.

2010: Life technologies markets numerous new technologies (semiconductor
sequencing, capillary electrophoresis sequencing & fragment analysis, next-generation
sequencing, epigenetic sequencing, RNA & Transcriptome sequencing).

2011: Sequenom was the first company that offer prenatal screening from a mother’s
blood. MarteniT21 test available in October 2011.

2012: the scientific founder of Verinata, Stephen Quake, showed how in addition to
detecting extra chromosomes, sequencing the DNA in the blood of a pregnant woman
could reveal the full genetic code of a fetus, letter for letter.
(http://dnasequencing.yolasite.com/, 2015; Regalado, 2013; Rojahn, 2013)
Glossary of Terminologies:

DNA (deoxyribonucleic acid): the hereditary material in humans and almost all other
organisms. Nearly every cell in a person’s body has the same DNA. The information in
DNA is stored as a code made up of four chemical bases: adenine (A), guanine (G),
cytosine (C), and thymine (T) (Genetics Home Reference, 2015b).

Chromosome: in the nucleus of each cell, the DNA molecule is packaged into thread-like
structures called chromosomes (Genetics Home Reference, 2015a).

DNA sequencing: the process of determining the order of DNA building blocks
(nucleotides) in an individual’s genetic code. DNA sequencing is used to test for genetic
disorders.