DNA Sequencing: What Next?
According to the World Health Organization (WHO), 1 in every 33 children is born with a birth defect, and half of these diseases have no known cause. The WHO reports that in 2010, 3.1 million babies died from birth defects in 193 countries. Approximately 270,000 newborns each year die within the first 28 days of birth from congenital anomalies. Another 3.2 million children a year live, but with crippling disabilities as a result of their birth defects.
There's about a 3 percent chance of a child being born with a birth defect. Some may take comfort in the idea that 97 of 100 births result in a healthy baby. The parents of the other children born with a defect may not find those numbers so reassuring. As of now, little can be done for these parents. If some research companies have their way, however, there might be a lot more that can be done to help. Biotech firms are working with a technique called DNA sequencing that may help screen for birth defects while the baby is still in the womb. The technology isn't perfect yet, and raises some ethical questions, but it has the potential to help scientists and researchers study birth defects and find ways to predict which children could be born with them. It may even help someday with eradicating these diseases altogether.
What is DNA sequencing?
To explain the idea of DNA sequencing, a journey back to early biology classes is needed. Deoxyribonucleic acid (DNA) consists of four nucleotides: adenine, guanine, cytosine and thymine. All life is made up of these four basic building blocks.
In the 1970s, Frederick Sanger created a method for sequencing DNA quickly so as to discover the order of these nucleotides in humans. While Sanger's method was quicker than others in the past, it wasn't quick enough to sequence more than a few pairs of nucleotides a year. Scientists continued the work, however, and began the Human Genome Project in the 1990s. As technology advanced, laboratories were able to increase the number of genes that they could sequence, and eventually the Human Genome Project was completed.
Thanks to this breakthrough, scientists can study genetic differences between relatively healthy individuals and those with a disease to find out where in the string of nucleotides the disease corrupts the DNA.
How can this work for prenatal screening?
In 1997, scientist Dennis Lo discovered that up to 15 percent of the free-floating DNA in a pregnant woman's blood was constituted by the DNA of her child. Using the sequencing techniques that helped finish the Human Genome Project, scientists were able to reproduce finished copies of what the rest of the child's DNA strand would look like. With this information they could study the sequenced strands and count the number of chromosomes extant. Certain birth defects, like Down's Syndrome, can be detected this way. If a child has an extra chromosome 21, then that means they could be born with the disease. Now, with DNA sequencing, prenatal health care can include this type of screening.
The technology has advanced. Stephen Quake, a biophysicist from Stanford University and the founder of Verinata, was able to prove that DNA sequencing could produce the full genetic code of the unborn baby. Two separate teams were able to do this in China, as well as Jay Shendure, a scientist from the University of Washington. This can have huge medical implications. There are over 200 known birth defects that are caused by DNA mutations. Sequencing to produce the genetic code of a fetus can help doctors see these defects before the child is born. It could also help researchers discover the cause of another 3,000 diseases that may have their root cause in mutations in a strand of DNA.
In May 2013, a baby was born after his genome was tested and judged as healthy for in vitro fertilization, according to Susan Young's article in MIT Technology Review. Multiple embryos were analyzed, and one of the "healthy" ones was implanted.
What does DNA screening mean for the future?
While prenatal testing can have positive applications, some ethical questions have to be asked. What do parents do with the knowledge gained from having their child's genetic code sequenced? A law professor at Stanford, Henry Greely, expressed his concerns to Antonio Regalado of MIT Technology Review that parents could look for specific features such as a straight nose and curly hair. "How many parents are going to abort a fetus because of male pattern baldness? I don't think many. But it's probably more than zero."
Biomedicine offers a whole new frontier, where technology and science may be ahead of society. Health educators at universities devote themselves to advanced research where natural and computer sciences merge. The field of bioinformatics relies on sophisticated applications of databases, statistics, computers and mathematics for biological analyses such as DNA mapping and gene identification. Currently, few rules govern these medical advancements, and there is a scramble to create some guidelines.
Lo, the scientist who discovered that a child's DNA mixed with the blood of their mother while still in the womb, put the argument even more clearly. "I think we must use the technology in an ethical fashion and should refrain from analyzing things that are not life-threatening."
As Shendure explained to MIT Technology Review, "Technically, all this is possible before we've figured out whether we should be doing it. You've got the whole genome -- then what do you do with it? There are a lot of things that will have to get ironed out."
As with many technologies, these applications can be used for good or for ill. Doctors, scientists and lawyers need to work together to create a governing framework for the use of DNA sequencing and the knowledge it gives us about our children's genetic future. With stringent guidelines, the good that this emerging health care technology may do for families, and for the medical community as a whole, could outstrip potential negative ramifications. Millions of young lives may depend on it.
About the Author:
Jamar Ramos has been writing poetry and fiction for many years, and earned his bachelor’s degree in Creative Writing from San Francisco State University. For the last three years, Mr. Ramos switched to producing blog posts for CBSSports.com and writing professionally as an independent contributor for a number of Internet sites. His creative works have been featured in The Bohemian and The San Matean. He now contributes articles for OnlineDegrees.com, OnlineColleges.com, and AlliedHealthWorld.com.