DNA and You

Steven Pinker of the PGP in the NY Times Magazine

Very interesting article by Steven Pinker of the Personal Genome Project in the NY Times Magazine.  Check it out here.

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. 

Mandatory Waistline Measurement in Japan: Good Public Health Social Policy? Or Genetic Discrimination Against Fat People?

The NY Times has a really interesting piece on a new policy of mandatory waistline measurement in Japan.  With a goal of improving the public health, the government has established a state prescribed limit on male waistlines of 33.5 inches along with a limit of 35.4 inches for women...

No...I'm really not kidding.

Companies and local governments will apparently be required - under this new national law - to measure waistlines of those 40-74 years old during annual checkups.  Apparently, those not meeting the country's standard will be given dieting guidance if they do not meet the standard and do not lose the weight over 3 months (with subsequent escalation of the scrutiny and advice if folks are still too rotund at 6 months). 

Interestingly, the Japanese government intends to impose monetary penalties on entities (local governments and companies that fail to meet specific targets).

Although I am sure that the Japanese government has good intentions, this is a very interesting policy in light of the fact that obesity is a trait that can only be partially modified by behavioral change.  In other words, it is clear that obesity risk is to some extent a heritable trait, determined to some extent by one's genetic background, that can be difficult for some individuals to overcome.

Although this is an interesting and aggressive experiment aimed at reducing healthcare costs, it has the potential to result in further stigmatization of those affected by the obesity epidemic (something that is, no doubt, intended by the rule since it may result in public health benefits).  By imposing penalties on local governments and companies, the government is avoiding the appearance of discriminating against those with generous waistlines; however, this will create tremendous incentives on these entities to exert considerable pressure on individuals whose waists are over the limits. 

In sum, it's a bold social policy.  It may help with healthcare costs in the long-run, but is it genetic discrimination? 

What do you think?

Is it heritable? A new series on twin studies.

Twin studies are one of the foundations of modern human genetics.  Researchers take advantage of a basic biological fact (that identical or monozygotic twins share essentially 100% of their genomes while fraternal or dizygotic twins share 50%) to study to what degree certain traits (disease risk, etc.) are heritable (i.e., how much of the disease risk is conferred by the genes versus the environment or just random events). 

Twin studies offer a very interesting window into human genetics and can often be extremely thought-provoking.  Here at DNA and You, I will periodically point out an interesting twin study as food for thought.

For example, it is commonly assumed that any familial effect on political party choice is environmental in nature, but these authors set out to look into this in further detail.  Basically the results suggest that although there is a modest effect of genetics on political party choice, this is probably conferred through intermediate genetic influences on attitudes about key political debates and other things like church attendance and social class.