DNA and You

If You Think Wired Is a Good Place to Go for Medical Advice, Think Again...

Andrew Yates at Think Gene wrote today about the new Wired Wiki home genomics how-to guide, "Check Yourself for Genomic Abnormalities."  Check out Andrew's post for a great discussion of the maturity, or, rather, the lack thereof, of the personal genomics market.

Something caught my eye though as I read through "Check Yourself for Genomic Abnormalities" at the Wired Wiki site.  The wiki post describes several options for "checking yourself for genomic abnormalities": 1) Visit a Genetic Counselor; 2) Scan Your Whole Genome; and 3) Perform Lab Tests at Home. 

Interestingly, the author(s), who otherwise did an ok job of briefly explaining what genetic counselors do, utilized consideration of a diagnosis of celiac sprue as an example of a situation in which someone would want to see a genetic counselor rather than "scanning their whole genome" or "performing lab tests at home."

I think the world of Wired, but in case it is not clear to the early adopters out there...

Wired is probably not where you want to get your medical advice.

Celiac disease (aka gluten-sensitive enteropathy or non-tropical sprue), the condition mentioned in the hypothetical scenario, is diagnosed via a blood antibody test and small intestinal biopsies.  Thus, rather than seeing your local genetic counselor if you think you might have CD, you would do well to discuss it with your primary care doctor and a gastroenterologist. 

The wiki writer's confusion likely stems from the fact that genetic factors do play a role in risk for Celiac disease; however, the genetics are complex, and the genes involved are not deterministic.  For example, risk of Celiac disease is higher if you have certain forms ("alleles") of HLA genes.  About 30% of the population has one of the Celiac disease-associated HLA alleles; however, only 3% of individuals with the Celiac disease-associated allele develop CD.

Music and Your Genes: One Step Closer to Understanding the Biological Basis of Musical Ability

We've all come across certain people who seem to have a particularly high ability to play and/or appreciate music.  As a geneticist, my assumption has always been that this is inherent and heritable to some degree.  Nevertheless, it could certainly be argued that it is environmental. 

The literature provides some support for the concept that musical ability is genetic.  For example, musical talent has been noted to cluster in some families.  Additionally, the ability to identify pitch in the absence of a reference pitch clusters in families, as well.  Conversely, tone deafness, also known as congenital amusia, also seems to be genetic on the basis of strong familial clustering.  Lastly, in a formal study of pitch recognition in twins, the heritability of scores on the so-called Distorted Tunes Test were estimated to be more than 70%.

Now, a Finnish research group has demonstrated that it is highly likely that a gene on chromosome 4 (located in the vicinity of chromosome band 4q22) influences musical aptitude.  They utilized three different measures of musical aptitude in coming to this conclusion and performed a "genome-wide linkage test."  This study has narrowed the region containing the gene to a segment of the chromosome containing ~50 genes, so further studies will be necessary to find the precise genetic change influencing musical aptitude in these families. The authors also noted other regions of the genome in which there was suggestive linkage, suggesting that musical aptitude is likely to be affected by multiple genes.  It will be interesting to watch as these are hopefully identified in future studies.

Reference

K Pulli et al.  Genome-wide linkage scan for loci of musical aptitude in Finnish families: evidence for a major locus at 4q22.  Journal of Medical Genetics 45: 451-6, 2008. 

Is it heritable? Twin study evidence suggests acne can be inherited

Have you ever wondered whether acne risk can be inherited?  Twin studies can shed light on this question.

In a previous post, I discussed twin studies which are the genetic gold standard to determine whether the liklihood of developing a given medical condition (or trait) is subject to heritable (i.e., genetic) influences.  The concept is fairly simple: Identical twins share essentially 100% of their genetic material while fraternal twins share 50%.  If genetics plays a strong role in risk for a disease, when twin pairs in which one member has the disease are studied, both twins will have the same disease in a larger percentage of the identical twin pairs as compared to the fraternal twin pairs. 

One study applied this concept to the study of acne.  The results were clear: in this study, approximately 80% of the degree to which acne severity varied was due to genetic effects. 

Although the underlying causative genes are not known, the fact that genetics plays such a large role in the development of acne suggests that future efforts to find the underlying genes are likely to reveal new drug targets.

High Throughput Sequencing, Moore's Law, The Next Generation, and Storage Options

It will be interesting to see if DNA sequencing technology continues to follow a Moore's law-like trajectory over the coming decades.  Clearly, next generation technologies are going to have a massive impact both in the research setting and on medical resequencing. 

Alexis Madrigal at Wired Science wrote a nice piece on the technological advances leading to the current generation of high-throughput sequencers and also the next generation: Pacific Biosciences and Helicos.

Also notable is a post from the always excellent Daniel MacArthur at Genetic Future on options for storage of personal genome sequences.