June 7th, 2012
05:24 PM ET
Baby's DNA constructed before birth
Mom gave a blood sample. Dad spit. The entire genome of their fetus was born.
Researchers at the University of Washington have, for the first time, done a near-total genome sequence of a fetus in this way. Scientists published the results of this study in the journal Science Translational Medicine, suggesting that thousands of genetic diseases could be detected in children while they are still in the fetal stage.
Everyone has two copies of the human genome: One inherited from their biological mother and one from the biological father. With technology that's being used for genetic sequencing these days, it's not possible to say which variants on the chromosome you inherited from which parent.
Scientists also sequenced the cell-free component of the mother's blood - called the plasma - where about 10% of the DNA circulating is from the child, and the other 90% is from the mother. That introduces some difficulty, since it's hard to tell exactly what comes from the child.
Currently at least some component of diagnosis for genetic disorders in certain circumstances is done using technologies such as amniocentesis, which involves taking a sample of the fluid in the sac that surrounds the fetus in the womb - the mother has to have a needle inserted into her uterus, which is a lot more complicated than a simple blood test and carries some health risks.
"This might reduce the need to do invasive testing for fetuses," said Jay Shendure, associate professor of genome sciences at the University of Washington.
The focus of the study was the genome of a fetus whose mother's blood sample was taken at 18 weeks. The analysis of her blood, the father's saliva and the plasma contributed to a nearly full picture of the fetus's genome. This model showed that the fetus had 39 mutations that it had not inherited from either parent.
To confirm, researchers looked at the baby's umbilical cord blood after it was born. In comparing the constructed DNA (from mom & dad's samples) and this cord sample, researchers found five additional mutations that hadn't come from the mother or the father. On the whole, the baby's artificially constructed genome using material from the parents was more than 98% accurate.
Researchers repeated the procedure on a different couple. This time the mother was only eight weeks pregnant when she donated her sample, and the father submitted a blood sample, which was processed in the same way that the other father's saliva was. This resulted in a fetal genome sequence that was 92% accurate.
"We could have brought it higher just by sequencing her plasma more deeply," said Jacob Kitzman, lead study author and graduate research fellow at the University of Washington.
There are also parts of the genome that technology available today just cannot measure very well, Kitzman says, so that's partly why there's not a 100% accuracy here.
Is gender selection of a fetus ethical?
Eight weeks are, however, well before mothers are able to get amniocentesis, which is often used at around 16 weeks.
It took more than a month to get the results from the sequencing, which is a lot longer than would be ideal in a clinical situation, Kitzman noted. In order to become more widespread, the technique would have to be easier to administer, quicker and less expensive.
So how much does this cost? Right now, in the ballpark of $50,000, Shendure says - and while that seems like a lot, keep in mind that this whole process involved sequencing the genomes of the mother and the father, separately analyzing the plasma and then double-checking the result with a sequence from the child's umbilical cord.
The price tag for sequencing has dropped by 10,000 fold in the last five years, Shendure says, so he expects this fetal genome technique will also become less expensive over time.
In the long-term, the technique may even help garner new insights about genetic diseases, but more immediately it would be restricted to identifying the genetic disorders that we already understand, he said.
"Whether this is the sort of thing we would do on a widespread basis for all pregnancies, that’s an open question and a complex one," he said.
The complexity comes, of course, from the ethical issues that arise concerning parents who would selectively abort fetuses that are predestined for certain conditions.
The technology worries medical ethicist Harriet Washington, who fears parents could use genome sequencing to predict and selectively abort children that don't meet certain standards - not just for diseases, but for things like hair and eye color.
“If we don’t look at the dangers, if we adopt this Pollyanna attitude and only look at the benefits, then it’s really easy to end up in a situation where we are blindsided,” Washington said.
Perhaps one day, even intelligence scores or skills could be forecasted, creating a situation akin the movie "Gattaca" where babies are basically custom-created to suit the needs of parents who can afford the technology.
What do you think about all this? Share your thoughts in the comments.
About this blog
Get a behind-the-scenes look at the latest stories from CNN Chief Medical Correspondent, Dr. Sanjay Gupta, Senior Medical Correspondent Elizabeth Cohen and the CNN Medical Unit producers. They'll share news and views on health and medical trends - info that will help you take better care of yourself and the people you love.
Spot on with this write-up, I really believe this amazing site needs a lot more attention. I’ll probably be back again to read through more, thanks for the advice!
Everyone loves it whenever people come together and share ideas. Great blog, continue the good work!
Oh my goodness! Incredible article dude! Thank you, However I am going through issues with your RSS. I don’t know why I cannot join it. Is there anybody else having similar RSS problems? Anybody who knows the solution can you kindly respond? Thanks!!
Hi, I do think this is a great site. I stumbledupon it 😉 I am going to return once again since I book-marked it. Money and freedom is the best way to change, may you be rich and continue to help others.
Hi there! This blog post couldn’t be written any better! Reading through this post reminds me of my previous roommate! He always kept preaching about this. I am going to send this article to him. Fairly certain he's going to have a good read. Thanks for sharing!
cyclosporine medication cyclosporine pharmacology
I used to be able to find good information from your articles.
I could not refrain from commenting. Exceptionally well written!
An impressive share! I've just forwarded this onto a coworker who was conducting a little research on this. And he actually ordered me breakfast simply because I discovered it for him... lol. So let me reword this.... Thanks for the meal!! But yeah, thanks for spending some time to discuss this matter here on your site.
Aw, this was an exceptionally good post. Taking a few minutes and actual effort to generate a top notch article… but what can I say… I put things off a whole lot and don't manage to get anything done.
Right here is the right website for everyone who wishes to understand this topic. You realize a whole lot its almost tough to argue with you (not that I personally would want to…HaHa). You certainly put a new spin on a topic which has been written about for decades. Great stuff, just great!
After I originally commented I appear to have clicked the -Notify me when new comments are added- checkbox and now every time a comment is added I recieve four emails with the exact same comment. Is there a means you are able to remove me from that service? Many thanks!
The very next time I read a blog, Hopefully it doesn't disappoint me as much as this one. After all, Yes, it was my choice to read, but I genuinely believed you'd have something interesting to say. All I hear is a bunch of moaning about something you could possibly fix if you weren't too busy looking for attention.
Your style is unique in comparison to other people I have read stuff from. Thanks for posting when you have the opportunity, Guess I'll just bookmark this web site.
Great post. I'm going through many of these issues as well..
Way cool! Some very valid points! I appreciate you writing this post and the rest of the website is also really good.
Right here is the right site for everyone who hopes to understand this topic. You know a whole lot its almost hard to argue with you (not that I really would want to…HaHa). You certainly put a fresh spin on a subject which has been discussed for years. Great stuff, just wonderful!
Hi there, I believe your site may be having web browser compatibility issues.
Whenever I look at your website in Safari, it looks fine but when opening in IE, it has some overlapping
issues. I merely wanted to provide you with a quick
heads up! Besides that, fantastic blog!
You should take part in a contest for one of the finest websites on the net. I will highly recommend this website!
I'd like to thank you for the efforts you have put in writing this website. I really hope to view the same high-grade blog posts by you later on as well. In truth, your creative writing abilities has motivated me to get my own website now 😉
Good site you have got here.. It’s hard to find excellent writing like yours these days. I seriously appreciate individuals like you! Take care!!
After I initially commented I appear to have clicked on the -Notify me when new comments are added- checkbox and now each time a comment is added I get 4 emails with the exact same comment. Is there a way you can remove me from that service? Thank you!
Spot on with this write-up, I seriously believe this web site needs a lot more attention. I’ll probably be back again to read more, thanks for the advice!
Great post. I will be going through a few of these issues as well..
I couldn’t refrain from commenting. Perfectly written!
I have to thank you for the efforts you have put in penning this website. I'm hoping to view the same high-grade content from you later on as well. In truth, your creative writing abilities has motivated me to get my very own site now 😉
I seriously love your website.. Great colors & theme. Did you build this amazing site yourself? Please reply back as I’m trying to create my own site and want to find out where you got this from or what the theme is named. Cheers!
Greetings! Very useful advice in this particular post! It is the little changes that produce the greatest changes. Many thanks for sharing!
I was able to find good information from your blog posts.