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Epigentics and Heredity

This is from the science section of the New York Times, 3 Dec 2015. The heading reads: "Fathers May Pass Down More Than Just Genes, Study Suggests."

Epigentics according to my dictionary means "Biology relating to or arising from nongenetic influences".

In Denmark, scientists are investigating the hypothesis that a man's experiences can alter his sperm, and that those changes in turn may alter his children. The standard view is that people inherit genes that predispose them to various conditions, like maybe obesity, stress, cancer or none of these. According to the article, animal experiments in recent years have challenged conventional thinking on heredity, suggesting that something more is at work.

Genes are regulated by swarms of molecules. These molecules can respond to environmental influences by silencing some genes and activating others as needed. Some studies suggest the changes in epigenetic factors can be handed down to offspring via sperm. The question remains, for example, whether a father's obesity can make his offspring more inclined to be obese. An epigenetics expert, Dr. John M Greally, at the Albert Einstein College of Medicine, in New York, has expressed doubt, saying, "Honestly, I think a lot of what they have is noise"

Another article on this subject appears in Science Daily on July 17 2017. It summarizes research at the Max Planck Institute of Immunobiology and Epigenetics in Freiburg, Germany:

Our study indicates that we inherit more than just genes from our parents. It seems to be that we also get a fine-tuned as well as important gene regulation machinery that can be influenced by our environment and individual lifestyle. These insights can provide new ground for the observation that at least in some cases acquired environmental adaptations can be passed over the germ line to our offspring," explains Nicola Iovino. Further, since the disruption of epigenetic mechanisms may cause diseases such as cancer, diabetes and autoimmune disorders, these new findings could have implications for human health.

There is the old Lamarck theory of biological inheritance from the last 1700s involving physiological changes acquired over the life of an organism, like muscle enlargement, being transmitted to offspring. This was before Gregor Mendel (1822-84) and his genetics. Darwin didn't know genetics but was interested in biological inheritances — creatures giving birth to offspring that were mutant in ways that allowed survival and these mutations being passed on to their offspring. Joseph Stalin was a Darwinist who disputed the existence of genes. He supported a Soviet agrobiologist named Lysenko who disputed gene theory in favor his theory of environmentally acquired inheritance. Scientists in the Soviet Union in 1948 were not allowed to dissent from Lysenko's theory, and in the West there was ridicule describing many generations of acquired characterists and progress that cows could be taught to work complex math problems.

I gather that none of the studies I'm reading are describing acquired characteristics that could eventually allow us to teach cows to do astounding things. But are those people who have grown bigger because of better eating passing their bigger size to their offspring genetically? And if so, will humanity eventually become giants? Or will environmental factors limit growth — like bigger people needing more food?

What role do acquired characteristics play in our immune system, for better or worse?

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