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.
This is a really good tip particularly to those fresh to the blogosphere. Simple but very precise info… Many thanks for sharing this one. A must read post!
This is a really good tip particularly to those fresh to the blogosphere. Simple but very precise information… Many thanks for sharing this one. A must read article!
Very nice blog post. I certainly love this website. Thanks!
Great site you have got here.. It’s hard to find excellent writing like yours nowadays. I really appreciate people like you! Take care!!
You made some really good points there. I checked on the net to find out more about the issue and found most individuals will go along with your views on this website.
Greetings! Very helpful advice in this particular post! It is the little changes that produce the most significant changes. Thanks a lot for sharing!
After looking at a handful of the articles on your website, I seriously like your way of blogging. I saved it to my bookmark site list and will be checking back in the near future. Please check out my web site too and let me know what you think.
I absolutely love your blog.. Very nice colors & theme. Did you develop this amazing site yourself? Please reply back as I’m hoping to create my own site and want to learn where you got this from or what the theme is called. Kudos!
You're so awesome! I don't suppose I have read through a single thing like that before. So good to find someone with some unique thoughts on this issue. Really.. thank you for starting this up. This website is something that is needed on the web, someone with a bit of originality!
You're so interesting! I do not believe I've read through something like that before. So great to find another person with some genuine thoughts on this subject. Really.. many thanks for starting this up. This website is something that's needed on the internet, someone with some originality!
Next time I read a blog, I hope that it won't disappoint me just as much as this one. I mean, I know it was my choice to read through, however I truly thought you would have something useful to say. All I hear is a bunch of complaining about something you could fix if you were not too busy seeking attention.
I seriously love your site.. Great colors & theme. Did you create this site yourself? Please reply back as Iím trying to create my own blog and want to learn where you got this from or just what the theme is called. Appreciate it!
This is a topic that is close to my heart... Thank you! Exactly where are your contact details though?
This excellent website definitely has all of the information I needed about this subject and didnít know who to ask.
Best view i have ever seen !
what is tadalafil cialis tadalafil side effects
May I simply just say what a comfort to find someone who actually knows what they're discussing online. You actually understand how to bring a problem to light and make it important. More and more people really need to read this and understand this side of the story. I was surprised you are not more popular because you surely possess the gift.
Iím impressed, I must say. Seldom do I encounter a blog thatís equally educative and entertaining, and let me tell you, you've hit the nail on the head. The issue is an issue that too few people are speaking intelligently about. I am very happy I stumbled across this during my search for something concerning this.
I would like to thank you for the efforts you have put in writing this blog. I'm hoping to see the same high-grade blog posts by you later on as well. In fact, your creative writing abilities has inspired me to get my own, personal blog now 😉
Hi there, I think your site might be having browser compatibility problems. When I look at your site in Safari, it looks fine however, when opening in Internet Explorer, it's got some overlapping issues. I just wanted to provide you with a quick heads up! Other than that, great blog!
Pretty! This has been a really wonderful post. Many thanks for supplying these details.
An outstanding share! I've just forwarded this onto a colleague who had been doing a little homework on this. And he actually ordered me lunch because I stumbled upon it for him... lol. So allow me to reword this.... Thanks for the meal!! But yeah, thanx for spending some time to talk about this matter here on your web site.
After looking over a handful of the blog posts on your web site, I honestly appreciate your way of writing a blog. I bookmarked it to my bookmark website list and will be checking back in the near future. Take a look at my web site as well and tell me your opinion.
Howdy! I could have sworn Iíve been to your blog before but after browsing through a few of the articles I realized itís new to me. Anyhow, Iím certainly pleased I found it and Iíll be bookmarking it and checking back frequently!
I need to to thank you for this great read!! I absolutely enjoyed every bit of it. I've got you saved as a favorite to check out new stuff you postÖ
Good web site you have here.. Itís hard to find high quality writing like yours these days. I truly appreciate people like you! Take care!!
Way cool! Some very valid points! I appreciate you writing this article and the rest of the site is also very good.
chloraquine latest news on hydroxychloroquine chloroquine phosphate vs chloroquine sulphate
Excellent article! We are linking to this particularly great post on our site. Keep up the good writing.
I really like reading an article that can make people think. Also, thank you for permitting me to comment!
After I originally commented I appear to have clicked the -Notify me when new comments are added- checkbox and now whenever a comment is added I recieve four emails with the exact same comment. Perhaps there is a way you are able to remove me from that service? Cheers!