So far in this course we have dealt entirely with the evolution of characters that are controlled by simple Mendelian inheritance at a single locus. There are notes on the course website about gametic disequilibrium and how allele frequencies change at two loci simultaneously, but we didn’t discuss them. In every example we’ve considered we’ve imagined that we could understand something about evolution by examining the evolution of a single gene. That’s the domain of classical population genetics. For the next few weeks we’re going to be exploring a field that’s actually older than classical population genetics, although the approach we’ll be taking to it involves the use of population genetic machinery. If you know a little about the history of evolutionary biology, you may know that after the rediscovery of Mendel’s work in 1900 there was a heated debate between the “biometricians” (e.g., Galton and Pearson) and the “Mendelians” (e.g., de Vries, Correns, Bateson, and Morgan). Biometricians asserted that the really important variation in evolution didn’t follow Mendelian rules. Height, weight, skin color, and similar traits seemed to

Human biochemical genetics

We studied physical fitness and risk of all-cause and cause-specific mortality in 10 224 men and 3120 women who were given a preventive medical examination. Physical fitness was measured by a maximal treadmill exercise test. Average follow-up was slightly more than 8 years, for a total of 110 482 person-years of observation. There were 240 deaths in men and 43 deaths in women. Age-adjusted all-cause mortality rates declined across physical fitness quintiles from 64.0 per 10 000 person-years in the least-fit men to 18.6 per 10 000 person-years in the most-fit men (slope, —4.5). Corresponding values for women were 39.5 per 10 000 person-years to 8.5 per 10 000 person-years (slope, —5.5). These trends remained after statistical adjustment for age, smoking habit, cholesterol level, systolic blood pressure, fasting blood glucose level, parental history of coronary heart disease, and follow-up interval. Lower mortality rates in higher fitness categories also were seen for cardiovascular disease and cancer of combined sites. Attributable risk estimates for all-cause mortality indicated that low physical fitness was an important risk factor in both men and women. Higher levels of physical fitness appear to delay all-cause mortality primarily due to lowered rates of cardiovascular disease and cancer. ( JAMA . 1989;262:2395-2401)

Physical Fitness and All-Cause Mortality: A Prospective Study of Healthy Men and Women

SUMMARYACSM Position Stand on The Recommended Quantity and Quality of Exercise for Developing and Maintaining Cardiorespiratory and Muscular Fitness, and Flexibility in Adults. Med. Sci. Sports Exerc., Vol. 30, No. 6, pp. 975-991, 1998. The combination of frequency, intensity, and duration of chr

http://myweb.facstaff.wwu.edu/chalmers/pdfs/acsm position stand - quantity and quality of exercise.pdf

ACSM Position Stand: The Recommended Quantity and Quality of Exercise for Developing and Maintaining Cardiorespiratory and Muscular Fitness, and Flexibility in Healthy Adults

Chronic diseases are major killers in the modern era. Physical inactivity is a primary cause of most chronic diseases. The initial third of the article considers: activity and prevention definitions; historical evidence showing physical inactivity is detrimental to health and normal organ functional capacities; cause vs. treatment; physical activity and inactivity mechanisms differ; gene-environment interaction [including aerobic training adaptations, personalized medicine, and co-twin physical activity]; and specificity of adaptations to type of training. Next, physical activity/exercise is examined as primary prevention against 35 chronic conditions [Accelerated biological aging/premature death, low cardiorespiratory fitness (VO2max), sarcopenia, metabolic syndrome, obesity, insulin resistance, prediabetes, type 2 diabetes, non-alcoholic fatty liver disease, coronary heart disease, peripheral artery disease, hypertension, stroke, congestive heart failure, endothelial dysfunction, arterial dyslipidemia, hemostasis, deep vein thrombosis, cognitive dysfunction, depression and anxiety, osteoporosis, osteoarthritis, balance, bone fracture/falls, rheumatoid arthritis, colon cancer, breast cancer, endometrial cancer, gestational diabetes, preeclampsia, polycystic ovary syndrome, erectile dysfunction, pain, diverticulitis, constipation, and gallbladder diseases]. The article ends with consideration of deterioration of risk factors in longer-term sedentary groups; clinical consequences of inactive childhood/adolescence; and public policy. In summary, the body rapidly maladapts to insufficient physical activity, and if continued, results in substantial decreases in both total and quality years of life. Taken together, conclusive evidence exists that physical inactivity is one important cause of most chronic diseases. In addition, physical activity primarily prevents, or delays, chronic diseases, implying that chronic disease need not be an inevitable outcome during life.

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Lack of exercise is a major cause of chronic diseases

Objectives—Although the effects of exercise on neurocognition have been the subject of several previous reviews and meta-analyses, they have been hampered by methodological shortcomings and are now outdated as a result of the recent publication of several large-scale randomized controlled trials (RCTs). Methods—We conducted a systematic literature review of RCTs examining the association between aerobic exercise training on neurocognitive performance conducted between January, 1966 and July, 2009. Suitable studies were selected for inclusion according to the following criteria: randomized treatment allocation, mean age ≥ 18 years of age, duration of treatment > 1 month, incorporated aerobic exercise components, exercise training was supervised, the presence of a nonaerobic-exercise control group, and sufficient information to derive effect size (ES) data. Results—Twenty-nine studies met inclusion criteria and were included in our analyses, representing data from 2,049 participants and 234 effect sizes. Individuals randomly assigned to receive aerobic exercise training demonstrated modest improvements in attention and processing speed (g = .158 [95% CI: .055 to .260], P = .003), executive function (g = .123 [95% CI: .021 to . 225], P = .018), and memory (g = .128 [95% CI: .015 - .241], P = .026). Conclusions—Aerobic exercise training is associated with modest improvements in attention and processing speed, executive function, and memory, although the effects of exercise on working memory are less consistent. Rigorous RCTs are needed with larger samples, appropriate controls, and longer follow-up periods.

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Aerobic exercise and neurocognitive performance: a meta-analytic review of randomized controlled trials.

Heritability of adaptive variation.

EUROFIT - European test of physical fitness

Adaptation to maximal effort: genetics and age.

Identical male twins (four sets aged 10 yr, four sets aged 13 yr, and four sets aged 16 yr) were divided so that one twin underwent strenuos endurance training for 10 wk, while his brother served as a control without training. Intrapair comparisons of the training-period changes in aerobic, anaerobic, and cardiorespiratory responses to maximum work on a bicycle ergometer disclosed that 1) 10-yr-old trained twins improved more than untrained twins did in VO2max,2) 16-yr-old trained twins increased their VO2max, O2 pulse, blood lactate, ventilation, and respiratory rate and decreased their maximal heart rates more than their untrained counterparts did, and 3) the trained and the untrained 13-yr-old twins changed commensurately. Further, interage comparisons of the intrapair differences showed that both the 10- and 16-yr olds improved their VO2max more than did the 13-yr olds. In view of this evidence, the old hypothesis that more may be gained by introducing extra exercise at the time when the rate of growth is greatest is not tenable.

Growth and physical training with reference to heredity

The general consensus among sport and exercise genetics researchers is that genetic tests have no role to play in talent identification or the individualised prescription of training to maximise performance. Despite the lack of evidence, recent years have witnessed the rise of an emerging market of direct-to-consumer marketing (DTC) tests that claim to be able to identify children's athletic talents. Targeted consumers include mainly coaches and parents. There is concern among the scientific community that the current level of knowledge is being misrepresented for commercial purposes. There remains a lack of universally accepted guidelines and legislation for DTC testing in relation to all forms of genetic testing and not just for talent identification. There is concern over the lack of clarity of information over which specific genes or variants are being tested and the almost universal lack of appropriate genetic counselling for the interpretation of the genetic data to consumers. Furthermore independent studies have identified issues relating to quality control by DTC laboratories with different results being reported from samples from the same individual. Consequently, in the current state of knowledge, no child or young athlete should be exposed to DTC genetic testing to define or alter training or for talent identification aimed at selecting gifted children or adolescents. Large scale collaborative projects, may help to develop a stronger scientific foundation on these issues in the future.

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Vassilis Klissouras

Papers

Heritability of adaptive variation.

EUROFIT - European test of physical fitness

Adaptation to maximal effort: genetics and age.

Growth and physical training with reference to heredity

Direct-to-consumer genetic testing for predicting sports performance and talent identification: Consensus statement.