Tuesday, May 8, 2007

Dani's New & Hot :: New Theory of Environmental Inheritance

I see Lamarck written all over this....

The "Children of the 90s" research group, in collaboration with Bristol University found data that supported the theory that not only are genetic information and environmental influences important factors in how people grow as adults, but that a grandfather's and father's experiences can also affect a child's growth. The paper entitled, "Sex-specific, Male-line Transgenerational Responses in Humans" was published in the European Journal of Human Genetics in February 2006. The entire paper can be found here, or you can find a nice summary here.

The researchers found the following correlations:
1. Children whose grandfathers had limited access to food during his slow growth period (9-12 years old before puberty) lived longer.*

2. Sons whose fathers began smoking before 11 years of age had a higher BMI at 9 years old than sons whose fathers had started smoking later on in life.

3. Granddaughter mortality rates are linked to grandmother's access to food during her fetus/infant stage whereas grandson mortality rates are linked to grandfather's access to food during his slow growth stage.*

*The cross-generational data was collected from Overkalix, a community in Northern Sweden.

If the results of this study is valid (correlation may not mean causation), then it means that genes that are turned on/off during our lifetime due to certain experiences, remain so as we pass them onto our offspring. That is to say, our life experiences affects not only our somatic genome, but our germ line genome as well. This theory, if true, would have HUGE implications on our understanding of genetic inheritance. It also implies that our behavior now will have longterm effects on future generations, putting greater responsibility on us to live "better." And finally, it presents that possibility that evolution can be directed by our actions.

My Voyage of the Beagle review can be found here.

Beagle Quotes

"The character of the higher and more educated classes, who reside in the towns, partakes, but perhaps in a lesser degree, of the good parts of the Gaucho, but is I fear stained by many vices of which he is free. Sensuality, mockery of all religion, and the grossest corruption, are far from uncommon. Nearly every public officer can be bribed." (144)

"While in the boats I got to hate the very sound of their voices." (182)

"The perfect equality among the individuals composing these tribes, must for a long time retard their civilization. As we see those animals, whose instinct compels them to live in society and obey a chief, are most capable of improvement, so is it with the races of mankind." (183)

"I frequently got on their backs, and then, upon giving a few raps on the hinder part of the shell, they would rise up and walk away, but I found it very difficult to keep my balance." (279)


chickenpox said...

While these results are certainly interesting, it seems to me that there are far too many confounds to even begin to think about causation. Particularly for the smoking example, it's impossible to tell if there were certain genetic risk factors that made the fathers more likely to start smoking early and whether those factors that somehow led to smoking might be linked to the BMI results rather than the smoking itself. Or maybe, fathers that smoked earlier had less healthy behavior, and that's why their sons are heavier. The food examples seem slightly more legit, but still dubious.

In other words, I agree that these gene-environment interactions are important, they are also very complicated, and I think it's way too soon to start claiming that these modified genes could be passed down in the germ line.

chickenpox said...

oops, forgot to sign that!