Friday, June 20, 2008

Genes are not destiny

Way back, Art Devany had a post about two twins who, while having very similar genes ended up looking very different. One trained as a long distance runner and one in field events. One looked, well like a marathon runner and the other like a bodybuilder.

He explains:
Genes are not destiny; they are if/then off/on switches capable of enormous variation in output (proteins) when combined in signal cascades;
Rob Wolf commented on this idea Exercise and Gene Expression

We are not only born into this world with genes wired for certain types and ratios of foods but our genes are also best expressed when we are active. VERY active.

I recalled these posts today when I saw this story:

Lifestyle Can Alter Gene Activity, Lead To Insulin Resistance

A Finnish study of identical twins has found that physical inactivity and acquired obesity can impair expression of the genes which help the cells produce energy. The findings suggest that lifestyle, more than heredity, contributes to insulin resistance in people who are obese.

The story refers to this new article:

Acquired obesity and poor physical fitness impair expression of genes of mitochondrial oxidative phosphorylation in monozygotic twins discordant for obesity

Defects in expression of genes of oxidative phosphorylation in mitochondria have been suggested to be a key pathophysiological feature in familial insulin resistance. We examined whether such defect can arise from lifestyle-related factors alone. Fourteen obesity-discordant (BMI difference 5.2 ± 1.8 kg/m2) and 10 concordant (1.0 ± 0.7 kg/m2) MZ twin pairs aged 24-27 yr were identified among 658 MZ pairs in the population-based FinnTwin16 study. Whole body insulin sensitivity was measured using the euglycemic hyperinsulinemic clamp technique. Transcript profiles of mitochondrial genes were compared using microarray data of fat biopsies from discordant twins. Body composition of twins was determined using DEXA and maximal oxygen uptake (VO2max) and working capacity (Wmax) using a bicycle ergometer exercise test with gas exchange analysis. The obese co-twins had lower insulin sensitivity than their non-obese counterparts (M-value 6.1 ± 2.0 mg/kgLBM·min vs. 9.2 ± 3.2 mg/kgLBM·min, P<0.01). Transcript levels of genes involved in the oxidative phophorylation pathway (GO:0006119) in adipose tissue were lower (P<0.05) in the obese as compared to the non-obese co-twins. The obese co-twins were also less fit, as measured by VO2max (50.6 ± 6.5 ml/kgLBM·min vs. 54.2 ± 6.4 ml/kgLBM·min, for obese vs. non-obese, P<0.05), Wmax (3.9 ± 0.5 W/kgLBM vs. 4.4 ± 0.7 W/kgLBM, P<0.01) and also less active, by the Baecke leisure-time physical activity index (2.8 ± 0.5 vs. 3.3 ± 0.6, P<0.01). This would imply that acquired poor physical fitness is associated with defective expression of the oxidative pathway components in adipose tissue mitochondria.

"These data suggest that physical inactivity may have contributed to the defects in mitochondrial oxidative phosphorylation described in type 2 diabetic patients and prediabetic subjects," the authors wrote. The authors also noted that, although environment plays a role in how these genes work, there still may be a hereditary component.

You can't blame it all on your genes.....


Mark Sisson said...


On the other hand, you CAN blame it all on your genes, since they are just responding to the environment you choose to provide. Everything we do affects gene expression every second of every day. The only real differences among us are simply the ranges or degrees of possible gene expression for any one particular gene locus or set of related loci. That means that a 5′10″ person with “perfect mesomorphic tendencies” can still range in weight from 110 to 500 pounds depending on environmental influences on gene expression…or an ectomorph from 85 to 275 pounds, etc. Not all women with BRCA1 or BRCA2 get breast cancer even though their risk is far greater, etc etc. I posted on this recently at my site

Chris said...

Thanks Mark that is helpful.

I suppose what I was trying to highlight was the idea that it is often wrong for people to say that they are fat/unfit/unhealthy due to their genes alone.

Their behaviour is the key thing. It is like you say in that post:

"we are not at the mercy of our genes. How we play our genetic hand can matter as much as the cards we hold."

Thanks for the comment - I have huge respect for you and your writings.

Mark Sisson said...

Sorry if it sounded at all like I was disagreeing :-) I was agreeing wholeheartedly. Everything you talk about on your site here only works BECAUSE of gene expression (or else it doesn't work because of a different version of expression).

Seems my new goal in educating these days is to get people to see that we all have IMMENSE control over how we recreate ourselves through understanding gene expression and that using sites like conditioningresearch is the best way to "figure out" how to make your genes work for you instead of against you.

Keep up the great work.

Chris said...

Thanks Mark

Fredric Abramson said...

The changes in gene expression aren't random either. Not only do our genes respond to things like exercise, they respond often with pinpoint precision to specific chemical components of our diet. This specificity opens the door to think about calibrating our gene expression in a purposeful, goal oriented way.

This can be the ultimate in empowerment and control.

Dr. B G said...

Wonderful compilation of your insights and articles! I didn't know that DeVany wrote about these twins!

I did too... (but he gives them due discussion on mTOR -- love that pathway...Mmhhhh does Crossfit 'hit' it... I do believe so!!! Magnificently!!)

Gene expression is amazing -- we ticker with it by just eating and intensely moving... Our bodies are so fascinating aren't they? They have the capacity to heal and be whole, as they were meant to be. Whole mind, soul, and body... Often with a synergy with everything and everyone around (even those continents away! ;D)

Thanks for all your posts and ideas! Keep rockin' dude...


Chris said...

Thansk Doc

Anonymous said...

To keep your body healthy you have to reduce your body weight and ensure that it is with in the BMI range (BMI between 18.5 and 24.9). Exercise and well balanced diet are the best ways to prevent many diseases caused by over weight. Weight control methods can help you to keep your weight within normal BMI range.

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