David Shenk’s book, ‘The Genius in All of Us’ infers lifestyle influences hereditary.
The epigenome is the protective package of proteins around which genetic material – strands of DNA – is wrapped. The epigenome plays a crucial role in determining which genes actually express themselves in a creature’s traits: in effect, it switches certain genes on or off, or turns them up or down in intensity.
Shenk refers to experiments with chickens. His conclusion is that the environment can alter the epigenome, but what’s news is that those changes can be inherited.
Evolution says - In each generation, genes undergo random mutations, making offspring subtly different from their parents; those mutations that enhance an organism’s abilities to thrive and reproduce in its own particular environment will tend to spread through populations, while those that make successful breeding less likely will eventually peter out.
According to Shenk the environment also plays a role in creating those traits in future generations.
Likewise, Jerry Fodor’s book ‘What Darwin Got Wrong’, Natural selection, simply "cannot be the primary engine of evolution.
Could Shenk’s view explain Aurelius Augustine view that our sin nature is inherited?
I don’t think this claim has held up. Evidence for epigenetic inheritance of long-lasting traits is very thin, and some would say nonexistent. Epigenomic influences on gene expression are well known (for decades), and the idea that the environment influences the epigenome is well established, also not disputed. What remains unclear is whether such influences can span multiple generations.
I admit I laughed to think that the “sin nature” could be carried by histone modifications. Theologians would have to learn about enzymes!
Always good to hear from you. Hope this new year is good for you and yours.
My understanding of the research is that some epigenetic changes can span some generations. However, there is no evidence that epigenetics play any role in long-term changes. Instead, epigenetics provide a population with the ability to adapt to some transitory changes in the environment.
Am I on the right track?
Best,
Chris
P.S. @Paul_Allen1 Thanks for bringing the interesting issue to the forum! Given the limited, short-term role that epigenetics play in human inheritance, it does not seem to map very well to Augustine’s doctrine, in my opinion.
Nearly by definition, epigenetic processes are not thought to affect mutation rate, but in principle we can picture some of those processes having an impact. Last year a paper addressed this experimentally and found an association between epigenetic modifications and adaptive change. I have read only the abstract but it seems they did not study mutation rate, and they seem to suggest a model that doesn’t involve mutation rate. That’s the closest I have seen to anyone showing that “epigenetics affects the rates of mutation” but maybe it’s out there somewhere.
This is going to be very gene specific and species specific. There are known cases of transgenerational epigenetic inheritance in some species, most notably in nematodes and some plants. However, it is thought to be exceedingly rare to non-existent in complex vertebrates.
There are some basic questions that should be asked when looking at epigenetics:
What is the cellular mechanism that causes change in epigenetic markers? Very rarely do environmental factors directly influence epigenetics. Rather, there are cellular intermediates that sense the change in the environment and then cause changes in the epigenome further down a chain of cellular interactions. Therefore, epigenetic change is still dependent on the gene sequences of those intermediates, and is therefore still influenced by classic evolutionary mechanisms.
Which cells are being studied? One simple thing that many people forget is that if it doesn’t happen in egg or sperm then it isn’t heritable. Epigenetic changes that influence how brain or kidney cells function is interesting, but those cells aren’t used for reproduction. Any CpG methylation or histone packaging that happens in a kidney cell won’t be passed on.
Correlation does not prove causation. Unfortunately, many of the studies purporting to have discovered transgenerational epigenetic inheritance, especially in humans, are based on little more than correlation. They simply look for statistical anomalies, which will naturally happen in any data set, and then claim epigenetics is the cause. They need more than that. Specifically, they need a mechanism. They need to map epigenetic markers, show that those markers are present in gametes, and show how these markers influence offspring.
That was my question: Can such influences span multiple generations based on Shenk’s chicken and chick experiments to complex vertebrates when looking at research of separated human twins
Humans do many of the same things as animals. Good and bad. What separates us is emotional intelligence and abstract thought and ect…
Scripturally speaking though sin nature is not inherited. Sin is the choice to do what God said not to do. Many of our basic instincts, the same ones animals have, God told us to keep in control and use discipline. What made it a sin though was God calling it as such. That’s why even when a cat murders its own kittens, it did not sin because God had not govern it a moral codex. It’s free to pursue its own instincts and can learn what we as their owners want them to learn such as to stay off the counter and ect… they can seem to understand doing wrong. It’s not naturally evil for a dog to get on a chair. But we can teach them that it’s wrong and if they do they can even shy away showing guilt or
Fear of being sprayed by a water bottle and ect… it’s like a sin between a covenant they can grasp from us to them.
But as far as God goes, there is no covenant concerning morality with animals. So I don’t see any reason to believe that a sin nature is any more than a choice.