Posts Tagged: Genetic determinism

Standing the test of time

Tall 3If as a woman you have ever taken the metro in Asia, you may have found to your delight you can actually hold the handles hanging down from the bar without dislocating your shoulder. Western men may have to slouch on crowded public transport in Beijing if they wish to hold onto them. However, some retrofitting may soon be necessary on public transport in many Asian cities, since people – and men in particular – are getting taller. Perhaps as handles adapt, some will be left that women can use.
Likewise visitors to Southern Europe who are of Northern European stock may have noticed that they can now look most people in the eye. “The midgets are dying out,” laughed Teresa, a Portuguese woman. “Those extremely short, stocky men are almost nowhere to be seen; I was afraid for my son but he’s nearly 6 foot.”
It was assumed by many that Asians and Southern Europeans were genetically smaller, but there has been a spontaneous evolution in the space of a couple of generations. The average Chinese male is now 5 foot 8 (177cm) and the average American male 5 foot 9 (179cm). Women are the same height on both continents. The assumption is that good diet has caused this sudden growth spurt, although the Chinese eat few dairy products so the explanation for the tall Dutch doesn’t seem to apply. Is there a specific genotype for tall people? Or is it all diet and living conditions?

Tall 2There are of course areas of Asia where people are still significantly shorter. Interesting is the comparison between South and North Koreans, the former being 8cm taller than their Northern counterparts. This seems to be a direct result of the famines of the 1990s. The Chinese may have been bigger in the past too, to judge by the height of the Terracotta Warriors – all tall even by Western standards, standing at over 6ft (183cm), though perhaps warriors were selected because of their height. Conversely, the suits of armour in European castles seem to be made for rather short men, which correlates with the poor nutrition from which people in the Middle Ages so often suffered. Severe malnutrition is known to lead to stunted growth. Being tall has always been seen as an advantage, and today leg lengthening surgery is becoming popular in Asia, since tall people are expected to get better jobs.

Genetic determinism as far as height is concerned is therefore far from absolute. It has been observed that the heights of mother and son and of father and daughter correlate, but that is not the whole story. Height is determined by the complex interaction of genes and our environment – inner and outer. Our height depends not only on our own health during childhood, but also on that of our mother’s during pregnancy, and whether we suffered from neglect. Stress, once again, affects the body. If the stress is removed before adulthood, catch-up growth can occur, and can be significant. Diet, exercise, fitness, pollution exposure, sleep patterns, climate and even happiness are other factors that can affect growth and final height. Essentially, the developing body devotes energy to growth after other bodily and psychological functions are satisfied.

Even as adults, it is possible to change our height. The spine shortens and becomes compressed due to poor posture and gravitational pull (we are taller in the morning). It is possible to add up to 3 inches (7cm) to our height simply by stretching the spine. There are plenty of websites demonstrating what exercises help us to grow.

Tall 4The changes in average heights we are observing in populations we thought were short and stocky by nature show how quickly something we thought was a genetic factor can change given the right environment.

Genetic determinism is on its way out.

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Photo Credit: yushimoto_02 [christian] via Compfight cc
Photo Credit: Heaven`s Gate (John) via Compfight cc
Photo Credit: Gerard Kingma via Compfight cc

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Seven Ways to Change Your DNA

Is there anyone left who still believes in genetic determinism?
It is now accepted that DNA is not our destiny. While anyone claiming you can change your DNA would have been laughed out of the room a few years ago, once again science fiction has turned out to be fact, and the science of epigenetics shows that more than anything the environment – inner and outer – determines our health and longevity.
DNA change 2Obviously we are all born with a DNA sequence. Our general appearance is dictated at birth. However, lifestyle, our emotional world and what happens to us greatly affect how we look. These external factors to our DNA switch genes on and off all the time. The science of switching on genes is known as epigenetics.
Since the discovery of genes, a creeping victim mentality has overtaken the world. If we can do nothing about our genetic heritage then why bother trying to live longer and more healthily? Genetic determinism created a culture of irresponsibility and recklessness about our health. When your time’s up, your time’s up went the saying.
Not so fast. Even if a disease runs in a family, and even if we have inherited the gene for it, through lifestyle and mindfulness there is a huge amount we can do to prevent triggering that gene. Research (at the University of Bologna) is beginning to show that DNA can be altered through magnetic fields, positive mental states and – crucially though this is still controversial – intention.
Since all cells contain the same DNA, but differentiate to form skin, organs or bone for example, research is being done to reprogram cells back to a state where they can redifferentiate into any cell in the body.
So far it has been shown we can change our DNA expression in the following ways:

• Meditation. The relaxation response was studied in groups of individuals in the US, France and Spain. After just eight hours of meditation, the individuals showed molecular differences, altered levels of gene-regulation and reduced levels of pro-inflammatory genes, which promotes rapid recovery from stress.
“To the best of our knowledge, this is the first paper that shows rapid alterations in gene expression associated with mindfulness meditation practice,” says study author Richard J. Davidson, founder of the Center for Investigating Healthy Minds and the William James and Vilas Professor of Psychology and Psychiatry at the University of Wisconsin-Madison.
“Most interestingly, the changes were observed in genes that are the current targets of anti-inflammatory and analgesic drugs,” says Perla Kaliman, a researcher at the Institute of Biomedical Research of Barcelona, Spain where the molecular analyses were conducted.

• Therapy and changing learned behaviour. Eric Kandel the Austrian-American neuropsychiatrist and Nobel Prize winner has claimed that psychotherapy produces changes in gene expression that alter the anatomical pattern of nerve cells in the brain.

• Stress reduction techniques (leisure activities, changing negative thoughts etc..) These ‘psychosocial’ techniques are thought to change gene expression and alter brain structure.

• Intentionality. At the Institute of HeartMath in Boulder Creek, an experienced meditator was given three DNA samples and was instructed to unwind two through intentional visualisation. By creating a calm state of emotional and physical harmony the meditator succeeded in unwinding two samples and left the third unchanged. If further experiments confirm that this is possible, then DNA visualisation techniques in meditation are a powerful way of controlling our ageing and our health (see meditation blog entries).

• Exercise. Researchers compared activity in muscle-related genes before and after exercise. After a single 20 minute workout the participants’ DNA showed less methylation (a molecular process involved in ageing). Methylation is a process in which chemicals called methyl groups land on the DNA and limit the cells’ ability to access, or switch on, certain genes.

• Beliefs. Eric Kandel concluded that many genetic differences between us are due to conditioning and the society we grew up in, rather than fixed in the raw material we inherited from our parents. However, there is growing evidence that these epigenetic changes can be included in the DNA passed on to the next generation, a theory known as Lamarckism which until recently was discredited as an old wives’ tale.

• Diet. The following foods reduce DNA methylation:
– cruciferous vegetables, e.g. broccoli, cauliflower.
– foods high in folic acid, e.g. liver, egg yolk, dried beans.
– foods high in antioxidants, e.g. berries.
– foods high in vitamin B12, e.g. liver, meat, eggs.
– foods high in amino acids and B complex vitamins, e.g. spinach, eggs.

DNA change 399.9% of our genes are the same. The differences between us depend on which genes are switched on. This in turn depends on the environment and social conditioning of certain beliefs and behaviours.

So, good news again. We can control our destiny.

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