Lamarckism is the theory that organisms evolve not through survival of the fittest as Darwin argued, but by passing on acquired traits to their descendants.  For example,  you might naturally have a very scrawny body build, but if you spend all your time lifting weights, not only will you become more muscular, but you will biologically pass those muscles on to your son, and if he too lifts weights, he’ll pass on even more muscle to his sons, and in many generations, we’ll evolve into a race of incredible hulks.

Lamarckists believed that giraffes evolved long necks, not because only the longest necked giraffes survived (as Darwinists believe) but because by stretching their neck to reach food, they made them longer, and that extra length was somehow biologically inherited by the next generation, who would in turn stretch their necks even further, etc.

Lamarckism was famously discredited when a scientist chopped off the tails of mice for multiple generations and the mice were still born with tails.  This convinced scientists that you could not biologically pass acquired traits down to your children.  Lifting weights everyday might turn a scrawny nerd into a hulking  power lifter, however his son will still be born with the same scrawny build dad had before he started lifting weights, and the only way we would evolve into a race of hulks would be for the most naturally muscular people to have the most kids each generation, as Darwinists argue.

However with the rise of epigenetics, many people, including our very own Race Realist, have been arguing that Lamarck was somewhat right after all.  To oversimplify, epigenetics refers to chemical tags that are placed on the letters of our DNA sequence, that turn certain genes on or off, and some believe that not only can these tags be influenced by our life experience, but they can be passed on for many generations.

However when Race Realist tried to push this view at the West Hunter blog, scientist Greg Cochran would have none of it.  This is not surprising because Cochran’s skepticism towards such theories is well documented (see the 15 min mark in the below video):

Also expressing skepticism is scientist Richard Dawkins (see 2:40 mark in below video), though Race Realist feels this is largely because epigenetics undermines his “selfish gene” theory.

A major 2014 article by  Edith Heard and Robert Martienssen, published in the journal Cell, was every bit as skeptical as Cochran and Dawkins.  According to a summary of the Cell article by science writer Alex B. Berezow:

…characteristics many researchers assume to be the result of epigenetic inheritance are actually caused by something else. The authors list four possibilities: Undetected mutations in the letters of the DNA sequence, behavioral changes (which themselves can trigger epigenetic tags), alterations in the microbiome, or transmission of metabolites from one generation to the next. The authors claim that most epigenetic research, particularly when it involves human health, fails to eliminate these possibilities.

It is true that environmental factors can influence epigenetic tags in children and developing fetuses in utero. What is far less clear, however, is whether or not these modifications truly are passed on to multiple generations. Even if we assume that epigenetic tags can be transmitted to children or even grandchildren, it is very unlikely that they are passed on to great-grandchildren and subsequent generations. The mammalian epigenetic “reprogramming” mechanisms are simply too robust.

Therefore, be very skeptical of studies which claim to have detected health effects due to epigenetic inheritance. The hype may soon fade, and the concept of Lamarckian evolution may once again return to the grave.

 

Advertisements