Posts Tagged ‘ DNA ’

Genetically Engineered Babies: Good Or Bad Idea?

Wednesday, February 20th, 2013

Would you want the option of harnessing the power of genetics to alter the DNA of your unborn child? Would you want this to prevent disease? Select physical characteristics? Or “design” your baby by changing the genetic code? 

Such was the topic of an Intelligence Squared debate held in New York City on February 13. Two experts argued that genetic engineering should be banned; two experts argued that it should be supported. The audience – of which I was a part – had a chance to vote both before, and after, the arguments were made. Prior to the debate, I was in favor of supporting genetic engineering – with many caveats. After listening to both sides present their point of view, I pondered three points to help me come to a final decision:

Is genetic engineering feasible?

The science of genetics is fast paced. Although we don’t have much in the way of actual examples, it is worth assuming that it would be feasible at some point in the future. That said, my position is that it will only be worth considering for diseases or traits that are shaped by a single gene. There are certainly many diseases for which this is the case, such as cystic fibrosis and Huntington Disease. I certainly think there may come a time when it would be possible to try to intervene biologically to correct the mutations that underlie these conditions. However, bear in mind that most diseases and traits are believed to be due to the effects of many genes (polygenic) as well as environmental influences (multifactorial). Even height, which we think of as being “genetic”, is due to the combined effects of many genes as well as environment, and hence is multifactorial. Eye color is not as straightforward in terms of genetics as you might think. So … I think we can have the conversation about those more rare diseases and traits that are due to the “necessary and sufficient” effects of a single gene which can be identified along with the gene product. Having the debate about polygenic and multifactorial traits (more on this below) seems to be morphing into science fiction rather than science (unless science proves that wrong).

Why should we pursue it?

The primary reason would be to eradicate disease, especially disorders that are known to cause premature death. Certainly think about the life of a kid with cystic fibrosis – who wouldn’t want to spare a child that? Huntington Disease is an interesting example because it reveals that genes don’t just express themselves at birth – they can have a deleterious effect in adulthood. If we could alter that gene and prevent Huntington Disease, shouldn’t we do that? Some cases of breast cancer involve the primary (though not fully deterministic) effects of a single gene – again, if we could alter that mutation, wouldn’t we do that?

Why shouldn’t we pursue it?

Many feel that there are ethical considerations. For example, some do not like the idea of changing DNA – in essence, the thought is that it should be left alone. However, in terms of disease treatment, it’s worth noting that we do have examples of changing what a mutation does, and in the process keeping people healthy. A great example is a type of lymphoma caused by the “Philadelphia Chromosome” (so named because the mutation was discovered by scientists at the University of Pennsylvania). While the discovery was made in 1960, it took about 40 years to discover a genetically tailored drug that keeps the disease in check and allows people with this mutation to lead healthy lives. Although this isn’t genetic engineering in the strict sense, the principle is the same – alter the effects of DNA to change the likelihood of disease.

Less clarity surrounds the use of  genetic engineering to try to give parents the opportunity to control a variety of traits in their child to be – their appearance, personality, intelligence. As discussed by Melanie Abrahams, the pregnancy editor at Parents.com, the issue is would you want to create a Super Baby if you were given the choice? Again, my two cents to throw into this part of the debate is that it’s hard for me to imagine genetic engineering for polygenic, multifactorial traits – which includes appearance, personality, and intelligence. But then again, we don’t really know, do we?

Where do I land on this issue?

Bottom line, I support the idea of genetic engineering for well-defined diseases that are known to cause suffering and death. I don’t see any difference between designing a drug that is tailored to counter the biological effects of a mutation, and in principle directly altering the mutation. I don’t like the idea of applying genetic engineering principles to anything other than disease. Even “black or white” questions have their gray area.

DNA Structure via Shutterstock.com

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A (Very Brief) Primer On Genetics And Behavioral/Emotional/Developmental Disorders

Wednesday, November 28th, 2012

This will be brief.

There continues to be loads of information on the role of genetics on behavioral/emotional/developmental disorders. This pace will continue. But the big picture for parents can be elusive. So here is a primer.

Some disorders  are “genetic” in the classic sense—meaning they primarily have a genetic foundation. They tend to be very rare and distinctive. Examples are Fragile-X syndrome, and Down syndrome.

That said, most disorders these days are assumed to be “complex”—meaning that they arise from a combination of risk factors, both genetic and non-genetic in origin. In many cases, there may not be “one” definitive etiology but rather a range of causes that can vary from kid to kid. For example, it is believed that some cases of autism are due to rare genetic mutations (some of which may be associated with paternal age). But this type of causation may only account for a small fraction of the cases in the population. There may be a number of genes (some suggest it could be in the hundreds) that convey some level of risk for autism. And for these cases, the environment can also be a potent influence, as evidenced by recent twin studies. That said, the actual environmental factors remain elusive.

This idea of “complex” causation probably applies to the vast majority of behavioral/emotional/developmental disorders. ADHD is believed to be highly heritable—but there are no genetic markers that distinguish normative levels of inattention and hyperactivity from problematic ones. And just because ADHD is heritable, that doesn’t mean that the environment doesn’t matter. Biological environments (such as prenatal exposures) may play a role. The psychosocial environment is also very important in terms of shaping how ADHD gets expressed. In the case of “complex” disorders, genetics is often described as influencing “what is,” but not “what can be”—which is another way of saying that psychosocial interventions can be powerful approaches for altering behaviors that are “genetic” in origin.

We’ve learned a lot about genetics over the past few decades. We will continue to learn even more. But the reality right now is that, with the exception of rare “genetic” disorders, there is still more unknown than known about the role that genes play in the evolution of behavioral/emotional/developmental disorders. What we do know, though, is that environment matters. So whether we are talking about autism or ADHD or conduct problems or other issues, a parent’s best line of action is to get reputable psychosocial interventions that have been shown to work. Remember, genetics is, more times than not, more about “what is” rather than “what can be.”

Lab Experiment via Shutterstock.com

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Should Parents Get Their Kids Genome Sequenced?

Wednesday, October 31st, 2012

I just read a terrific series at Time.com about kids and DNA. One of the more intriguing questions posed was: Should you get your child’s genome sequenced? 

The idea might not seem far-fetched. We hear more and more about how genes predict whether or not we will get a disease. So why not have your child’s genome screened for disease genes?

Well, there are a few key considerations to keep in mind (without even thinking about cost or ethics):

Your child’s DNA was probably already screened for major disease genes (really big ones that have severe effects on development) when they were born.

Outside of those genes (there’s probably less than 100 of them), most genetic markers are really not that informative. They give you some sense of increased risk for a disease – but a whole host of environmental factors undoubtedly contribute as well. This is especially true for “common” diseases – like most of the behavioral and emotional disorders of childhood. The fact is for common disorders a fairly high proportion of the population carries some risk genes. So without the ability to offer more specific prediction (as is the case with some of the more rare genes that convey risk for breast cancer, the gene responsible for Huntington’s Disease, etc), it’s not really clear that DNA – right now – holds that much information on your child’s future in terms of common diseases that are influenced by both genes and environment.

Of course, the most important piece of information you would hope to get is not just if your child carries a gene, but what you could do to prevent disease onset. Outside of trying to reduce obvious risk factors that you would want to reduce anyway (e.g., if your child is at risk for diabetes, you would want to monitor their diet very carefully – but you want to do that anyway), there’s not much “genome-tailored” intervention out there.

The fact is that the more we learn about DNA, the more we realize that the landscape is even more complicated than we thought. Unless you think your child is at genetic risk for a disease, and unless there is a powerful genetic screen that carries real information that can inform and direct future behavior, there’s not much practical utility right now to sequencing your child’s genome.

DNA Fingerprinting via Shutterstock.com

 

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Same Genes, Different People: A Tale Of Two Twins

Friday, October 5th, 2012

I’ve been writing a lot about the complexities of determining how genes influence our behavior. The latest view from the genetics field is that the picture is getting more and more murky with increasing attention given to the multitude of ways in which DNA gets expressed. Despite that, we continue to get bombarded with suggestions that single genes are completely deterministic for highly complex human behaviors, like for example wanting to be a mom (click here for my take on the “mom gene”). The reality is that DNA is important and can be influential – but it is typically far from deterministic and all kinds of experiences can shape how DNA is expressed and have effects that go beyond what resides in an individual’s genome. There is no greater example of that than considering how identical twins can end being very different people even though they have the same DNA. To that end, blogger/editor Heather Morgan Shott (from High Chair Times, one of my personal favorite blogs out there) and her twin sister Erin Diebert graciously agreed to answer some questions on their experiences growing up as twins – and their recognition that they were, in fact, different people.

Note: Not Heather and Erin

1) Were you guys very similar when you were young? Did people confuse you? Were you dressed alike?

ERIN: Heather and I played together a lot before we entered elementary school. My mom dressed Heather and I exactly the same through first grade. After first grade, we chose to dress differently. Some people confused Heather and I.

HEATHER: We had very different personalities from birth. I was very impatient and wanted things the way I wanted them immediately, and Erin was more patient. I was the extrovert, she was the introvert. She worried a lot, and I was more carefree. As we grew older, some similarities did emerge; I suspect it’s a nature vs. nurture thing. Our differences as babies and toddlers were our natural personalities, whereas traits emerged as we got older based on how we were parented. We’re both worrywarts who try too hard to please other people (our mom is impossible to please and very highly strung).  We’re both ambitious (we were raised by a single mother who worked two jobs to support the family).

Our mom did dress us alike until first grade—that’s when we started Catholic school and were forced to wear uniforms. I suspect that she just decided to let us wear what we wanted when we weren’t in the classroom. And indeed we developed our own styles. Erin dresses for comfort, I dress for style.

People have confused us and excessively compared us. In college, we have totally different majors (and therefore different classes) and it wasn’t unusual for a professor to mistake one for the other out on campus. (We went to the same college.) The comparisons started around puberty when Erin became the “chubby” twin. It was awful. She struggled with her weight for some reason, whereas I didn’t and people always brought it up.

2) Did your parents make a point of raising you differently? Did you have different teachers?

ERIN: When Heather and I entered Fourth grade, we were put in separate classes.

HEATHER: We also had very different interest emerge, and those led us in separate directions. I was super immersed in the tennis team and the school paper. Erin was more introverted and spent her time studying. I excelled in English, Erin was excellent at science and math. And frankly our parents were so steeped in marital troubles for most of our childhood, even beyond the time they divorced (we were 8) that I don’t think they gave much thought to the importance of raising us to be individuals.

3) When did you start to notice (or looking back see now) that you were different people (different interests, abilities)?

ERIN: Heather and I knew that we were different very young, however, we enjoyed playing together when we were young. We felt very fortunate to have an instant “play date.”

HEATHER: Our differences were very well defined by the time we hit middle school. I was perceived as the mischievous one (and, OK, I was) whereas Erin was the one who always followed along. For example, one time Erin and I were preparing to be spanked. I decided that we’d both put a book down our pants so that the whacks didn’t hurt. My mom took Erin to spank, my dad took me. Fortunately for me, my dad thought my little trick was hilarious and he removed the book and hugged me. Erin, on the other hand, got whacked twice as hard. I was also the one who was in charge of setting up all the social plans, while Erin followed along. Erin, on the other hand, made sure that we signed up for ACT prep classes, etc. She kept me on track academically—or, at least, much more on track than I would have been at that age left to my own devices. I just wanted to write, I didn’t care about most of the subjects in school!

4) Did you guys try to “deidentify” when you were young? Or during your teens? (Some twins deliberately try to carve out individual paths)

ERIN: We tried to deidentify from fourth grade and older.

HEATHER: Agreed—especially me. I was the rebellious twin.

5) Any other insights on why you are different?

ERIN: Heather is very outgoing and confident. She joined a sorority in college. I’m also outgoing, but can be introverted at times. Heather likes to stay up late. I usually go to bed earlier. I have a medium group of close knit friends. Heather has many friends, some  of which are close friends.

HEATHER: At this point, a lot of our differences have to do with nurture. Erin still lives in the town where we grew up (Columbus, Ohio); I’ve lived on the East Coast for over 14 years.  I like big city life, and she prefers a more quiet existence.

6) How do you think you are very similar?

ERIN: We are both very compassionate and have had to deal with some very difficult issues going up. Our parents got divorced when we were 8. Our father chose to be out of our lives starting when we were in our early pre-teen years.

HEATHER: Agreed, along with a couple of points that I made above.

Thanks to Heather and Erin for sharing their stories and insights! 

Image of identical twins (not Heather and Erin) via Shutterstock.com

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Red-Hot Parenting Recap (Sept 2012): Play, DNA, And Sleep

Sunday, September 30th, 2012

Three big themes in the world of parenting stimulated discussion this past month. Here’s a recap of these along with links to posts that take them on. 

(1) The critical role of pretend play – long cherished in the academic literature and embedded in childhood education – was, to a degree, challenged by a somewhat provocative review paper. To some, it seemed like the article’s primary goal was to suggest that pretend play may be overrated as a promoter of cognitive development in general and creativity in particular, and hence should be reconsidered in a school’s curriculum. My take was a little different.  I thought the paper did a good job of highlighting the aspects of development that are positively influenced by pretend play – especially social skills – while suggesting that the cognitive aspects may in fact not be the primary benefit:

“Is Pretend Play Overrated?: The Take-Home Messages From The New Provocative Review”

The big thing for me was that, contrary to what you might have read about this paper, there was support for different types of play in the educational (and home) lives of young children (rather than suggesting to eliminate play). To wit, I also discussed a new study which revealed how drawing (particularly copying shapes) in toddlerhood predicts reading achievement in kindergarten even after accounting for traditional indicators of cognitive maturity:

Try This With Your Toddler: How A Particular Type of Drawing Is Associated With Reading Achievement In Kindergarten” 

(2) DNA was in the news in a number of ways. There was lots of interest in the recent link made between paternal age and risk for autism in offspring. Much was made of the idea that men, as well as women, have a biological clock. In response, I described what that may mean biologically, and how men (like women) may have to factor in rather inconclusive probabilities when making complex choices about having children at different ages:

Dads, DNA, And Choices

DNA and moms was also a hot topic. A study was characterized in the media as identifying “the mom gene” – implying that a woman either has, or hasn’t, a gene which would make her want to be a mom. I pointed out that genetics doesn’t typically work like this in humans, along with the, um, difficulties in making the jump from a study about female mice who had the function of a gene experimentally disabled to the human female:

Is There A Mom Gene?

(3) Sleep was also a big topic. While you may have read that a new study showed that it’s okay to let your baby “cry-it-out” the actual take-home messages were more fine-grained. In particular, the study was really about 2 types of sleep training methods, their utility in reducing infant sleep problems, and their lack of effects – positive or negative – 5 years later:

That “Cry-It-Out” Study: 5 Important Take-Home Messages You Should Know

I especially encourage you to check this out because we are finally seeing actual scientific studies on sleep training, rather than just debate. And the implications for parents are quite reasonable and, to my way of thinking, very important to know, given that all parents wrestle with figuring out how to get their babies to sleep.

 

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