Epigenetics Is Well Worth Learning
Once at dinner my son and I discussed homosexuality. I said sexual orientation is set in the womb, determined by genes; Xq28, FucM, Wnt-4, and Sphinx are among the so-called gay genes found so far. My son said that, per epigenetics, acquired environmental events can also turn a non-homosexual person homosexual.
I knew too little about epigenetics to judge, so I decided to understand it before continuing. My generation has no concept of it; my son, just a high-school freshman, has already learned it in biology.
It has been over twenty years since my school days; our textbooks had no epigenetics, and biology was not even on the college entrance exam. Back then epigenetics had not yet drawn general attention.
A biology postdoc had recommended Epigenetics and Precision Medicine, which I bought but have not read; I am still studying basic biology step by step and reading The Biology of Cancer he recommended.
But I have fragments of time, like before sleep on my Kindle, and to understand epigenetics I bought Lamarck's Revenge: How Epigenetics Is Revolutionizing Our Understanding of Evolution.
It is accessible; within half an hour I was hooked. It clearly explains epigenetics' past and present, its main content, and its impact on modern precision medicine. Anyone interested in life science will be drawn in.
The concept remains debated. Briefly, epigenetics refers to heritable changes in gene function without altering the DNA sequence, ultimately changing the phenotype and presenting diverse traits.
The acquired environment affects organisms: a lab mouse made slovenly in a dirty environment begets slovenly pups. Such environmental factors can alter and heritably transmit traits. Human and animal traits—height, skin color, blood type, enzyme activity, drug tolerance, even personality—depend not only on inborn genes but greatly on upbringing and major life events.
Before Darwin, the French naturalist Lamarck proposed an evolutionary theory distinct from Darwin's: organs used frequently develop, unused ones degenerate—the famous use-it-or-lose-it. Lamarck held such acquired traits are heritable; a drunkard's descendants may be alcoholics, a studious person's descendants may become scholars. Darwin disagreed, holding evolution slow and gradual, with life experiences not inherited.
Lamarck's famous example, later a scientific laughingstock: giraffe ancestors had short necks but stretched them to reach high leaves, evolving into today's giraffes. Though wrong, his basic idea has merit; his theory explains many phenomena Darwin's cannot.
In recent years biology has seen neo-Lamarckism, and epigenetics emerged. Especially as gene editing matured, people realized Lamarck was right. In his lifetime he was ridiculed; scientists cut mice's tails and mocked him that tailless mice bore tailed young. He died in poverty; his daughter wrote on his tombstone: 'One day the world will find you were right, and someone will avenge you.' This has now come true.
Epigenetics has hugely influenced modern precision medicine, and we can find echoes in TCM's basic theory. TCM holism holds human and environment as one; the Huangdi Neijing chapters on regulating spirit by the four qi and on resonance with life qi all discuss environmental influence. Studying TCM with modern epigenetics may reveal much; comparing ancient and modern thought inspires new discoveries, and Tu Youyou is a fine example.
Limited by its era, the Huangdi Neijing is far less precise than epigenetics and does not mention heritable environmental changes. But modern Japanese Kampo physicians have realized TCM body constitution can be inherited; Otani Keisetsu noted a father with a Guizhi Tang pattern often has a son with the same.
Epigenetics also reveals drug side effects should not be underestimated; some alter traits and cause teratogenic effects in offspring of patients.
Such side effects are not limited to Western medicine. The methyl group in banmao (cantharis) attaches to human DNA, causing adverse reactions; modern firms use norcantharidin instead, because even traditional processing cannot remove the highly toxic methyl. Cantharis causes irreversible, epigentic damage. Knowing this, we no longer recklessly use raw cantharis; I have seen many poisoning cases.
Safety and efficacy are medicine's highest pursuit. Medical students should range widely across life science, study deeply, and think carefully to avoid inadvertently taking lives.