On a related note, the results of this study are similar to the findings of earlier studies showing that disclosure of genetic test results does not lead to increased anxiety. Read more about this…

“It could be the perfect excuse for those who find exercise something of a chore: ‘I’m not lazy, it’s my genes.’ Scientists have discovered why some of us have the energy to work out for hours while others can barely summon the get-up-and-go to reach for the TV remote. They believe they have pinpointed the genes that produce an enzyme in our muscles during exercise called AMP kinase, which controls the way we turn food into energy. Those who generate large quantities of AMPK have more energy, whereas those with lesser amounts are likely to tire almost immediately. Dr Gregory Steinberg, who led the research, said the discovery could lead to treatments for those who find it difficult to exercise, including the obese and those with asthma. His team found dramatic results in tests on two groups of mice, one bred without the two suspected genes behind AMPK production.” – from “Gene that makes you a couch potato: Scientists discover why some people have all the energy… and others don’t” by Tamara Cohen, Mail Online. Read more…

If you’re interested in this article, you might also be interested in the DNAction blog post, “The Genetic Connection: Athletic Performance” by contributing author and Pathway scientist Dan Zhu.

“A new national survey of 800 American voters conducted by the Biotechnology Industry Organization shows that a majority of people — 53 percent — want the federal government to financially support the biotechnology industry, a BIO press release says. Even in a time of economic hardship, the survey respondents said the government should financially support the industry — either through tax incentives or direct funding — in order to cure disease, produce alternative energy sources, and create abundant food sources, BIO says. ‘The survey found that the key biotechnology industry issues are ranked by voters as either extremely or very important — behind only the economy, education, reducing the deficit/government spending — and alongside of issues such as combating terrorism and reducing taxes,’ the press release adds.”

Click here to download the survey results (PDF).
Click here to read the BIO press release.

The sugar known as lactose is the main carbohydrate component of milk, which is the only food source for newborns. The enzyme lactase is found in the small intestine, and is responsible for cleaving lactose into glucose and galactose, which can be absorbed into the bloodstream and used as a source of energy. An estimated 65% of adults are lactase non-persistent (or lactose intolerant) and downregulate the production of intestinal lactase after weaning (PMID 19034520, PMID 14616060). In others, lactase activity persists throughout adult life. Those who are lactose persistent (or lactose tolerant) are able to drink milk without any of the side effects experienced by people who are lactose intolerant.

It is not surprising that lactose intolerance results in the avoidance of dairy products. The fermentation of undigested lactose by bacteria in the colon can cause diarrhea, abdominal pain, flatulence, bloating and cramps. It is thought that variation in the gut flora may account for some of the differences in symptoms between people (PMID 19034520).

Family and twin studies have shown that genetics plays a role in lactose intolerance. In recent years, the rs4988235 (13910C>T) variant has been associated with lactase persistence as well as lactase enzyme activity in Caucasians (PMID 11788828, PMID 17659699, PMID 17311063, PMID 17706627, PMID 12914565).  The rs4988235 variant, in the MCM6 gene, has been proposed to act as a switch regulating expression of the nearby lactase gene (PMID 12915462, PMID 14724821). Individuals with one or two T alleles make sufficient lactase to digest lactose. Thus, people with the C/T or T/T genotype at rs4988235 are more likely to be lactose tolerant, while those with the C/C genotype are more likely to be lactose intolerant.

While rs4988235 almost completely explains the frequency of lactase persistence in Caucasians, it does not account for the frequency of lactase persistence worldwide, including populations in sub-Saharan Africa and Asia. In those populations, other variants have been found to be associated with this trait (PMID 20144208, PMID 17159977, PMID 19947896).

Your Pathway Fit® test can help you determine your genotype at the rs4988235 variant, and if you are lactose intolerant, you should make sure that you are getting enough calcium from non-dairy or lactose-free sources (PMID 20225268). On the other hand, if you are lactose tolerant, be aware that dairy products can be high in calories, fat, or both. A recent study of 17,374 Finnish people showed that those with the lactose tolerant genotypes (C/T or T/T) were more likely to have a higher BMI (body mass index) than those with the C/C genotype (PMID 20015952). Thus, you should manage your dairy intake appropriately.

“The movement comes in part from the feeling among some people that things aren’t moving fast enough in the life sciences. ‘We’re not curing cancer, we’re not moving ahead fast enough with things like biofuels’ and part of the problem is that the biotech world, in both academia and the corporate world, is too big, too slow and too closed,” says Marcus Wohlsen, author of Biopunk: DIY Scientists Hack the Software of Life.

Click here to read the full article…

Common wisdom holds that a marathoner is unlikely to excel in a 100-meter race, and vice versa. While it is easy to imagine that genetic variation is a major source of such differences in athletic ability, identifying the actual genetic causes requires careful characterization of athletic traits and in-depth data analysis.

The ACE (angiotensin-converting enzyme) gene is one of the earliest and most widely studied genes in sports genetics (PMID 19696508). Everyone carries two copies of the ACE gene and each copy of it is either an I allele or a D allele. In the I (insertion) allele, there is an extra 287-base pair fragment of DNA that is absent in the D (deletion) allele.

Both alleles are common and each person has one of the three possible ACE genotypes — I/I, I/D or D/D.

A number of studies have found that the frequency of the I allele is higher in elite endurance athletes than in non-endurance athletes or non-athletes. For instance, in a study involving Caucasian athletes who completed either the 2000 or 2001 South African Ironman Triathlons, there was an excess of the I allele in the 100 fastest finishers as compared to the 100 slowest finishers or to non-athletic individuals (PMID 15292738). In another study of elite runners selected by the British Olympic Association as potential members of the national Olympic team, the I allele was present at a higher frequency in long-distance runners than in short-distance runners (PMID 10517757). Similar findings have also been reported in other sport disciplines, such as high-altitude mountaineering (PMID 18081503, PMID 9607758) and rowing (PMID 9737775).

There is a clear negative correlation between the I allele and the ACE protein activity in Caucasians. The ACE protein is a key regulator of blood pressure and many other aspects of cardiac and vascular physiology. However, the role of ACE in athletic performance is still not well understood.

Unlike genetic studies of common diseases involving large patient cohorts, association studies of athletic performance typically have small sample sizes and limited statistical power. This is also true for studies that demonstrated the association of ACE with endurance performance. This association should be considered preliminary because there have been studies that failed to show this association (PMID 19696508). It is also notable that this genetic association has been documented mostly in Caucasians, while data from African subjects did not show the same genetic effect (PMID 15950509).

ACE alone is not enough to ace it, because based on the preponderance of data from the scientific literature, it is likely that, on average, athletes with one or two I alleles have a better chance to achieve top performance in endurance sports than those with the D/D genotype. However, this genetic effect should be kept in perspective because athletic performance is a complex trait and ACE is only one of the many contributing genetic factors. ACE is among a very small number of genes that have so far been studied for association with athletic performance; also the whole field of sports genetics is still at a rudimentary stage. Therefore, we cannot predict a person’s athletic potential based on his or her ACE genotype alone. Indeed, in all the studies mentioned above, there were individuals with the DD genotype who were elite endurance athletes.

Athletic performance is a perfect example of gene-environment interaction. In order to develop sporting prowess, even the most talented athletes need to train consistently and properly. The ACE genotypes have only a slight physiological effect that is largely unnoticed in non-athletes, but I allele carriers are likely to gain more benefit from endurance training than non-carriers (PMID 19696508); this enhanced training response may explain why athletes carrying the I allele have better endurance performance. In other words, both good genes and hard work are necessary ingredients for successful athletic achievement.

How does Pathway identify the genetic markers to include in its tests?

Pathway employs an army of geneticists whose primary responsibility is to read genetic studies to identify reportable genotype-phenotype associations that can be added to Pathway’s tests.  This curation process seeks rigorous scientific evidence that specific traits or conditions (phenotype) can be associated with specific changes in the DNA sequence of a gene (genotype).

You might have heard of museum curators, whose job it is to acquire artwork or historical items for museums.  Genetics curators at Pathway have the job of acquiring genetic data from the available literature.  The most widely used (and freely available) database of literature is PubMed, which is maintained by the National Library of Medicine.  PubMed contains information on over 20 million studies, and is growing at an astonishing rate of 1 paper per minute. The curators spend hours poring over studies in PubMed and in other databases to identify new markers with high scientific validity that can be added to Pathway’s tests. For any phenotype (for example, satiety in Pathway Fit®, or warfarin sensitivity in our drug response test) that is reported, a curator may read between 3 to 50 scientific papers.

A commitment to high scientific validity

The curation team at Pathway establishes criteria for identifying genotype-phenotype associations that can be reported.  For complex traits tested in Pathway Fit, drug response, and Health Insight, these criteria include study characteristics such as population size, statistical significance, and ethnicity.  Many of these items are included in guidelines sponsored by the U.S. Centers for Disease Control (CDC) for strengthening the reporting of genetic prediction studies (PMID 21434890).  For our Pre-Pregnancy Planning Insight™, we include mutations recommended  for carrier status screening by the American College of Medical Genetics and the American College of Obstetricians and Gynecologists.  For our drug response product, we look at recommendations for genetic testing that are approved by the Food and Drug Administration.

One universal criteria across all products is that the genotype-phenotype association must be found in human studies. Animal or in vitro studies are insufficient for reportability, although they may be additional support for a genotype-phenotype correlation found in humans.

Each genotype-phenotype association that is reported has passed a rigorous review process

For each genotype-phenotype association that is selected for reporting, the scientific evidence is reviewed by at least 4 Ph.D.-level geneticists. The initial curator identifies the genotype-phenotype association, and puts together a body of evidence (supporting documentation) to support the addition of the marker-trait to a particular test.  This literature is passed on to a second curator, who rereads the supporting documentation and looks for reasons that a marker-trait association cannot be reported.  For example, the trait may not be statistically significant or there may be studies showing conflicting results.  If the marker-trait passes this stage, the supporting documentation is delivered to the head of curation and chief scientific officer for approval.  If any assays need to be developed, scientists in research and development may also review the supporting documentation.  Thus, any new marker-trait association has been subjected to rigorous review.

Delivery of scientific valid test results with actionable recommendations

Curators write the initial draft of content for each test result.  This includes the description of the trait or condition, what each genotype result means, as well as some recommendations for lifestyle changes (if any).  For example, the C/C genotype at the rs4988235 marker in the MCM6 gene is associated with lactose intolerance (Pathway FIT). Non-dairy sources of calcium are recommended for people with this genotype.

The content for each test result is reviewed and edited by genetic counselors, physicians, and nutritionists.  A final review by the curation team ensures the validity of the test result.  Pathway’s intent is to deliver scientifically valid test results with actionable recommendations.