Today we are going to wander through a brief discussion of two theories of the very French, Jean Baptiste Lamark and the other, the more popular but less flashy Charles Darwin.
So. what about these two and the concept that flora and fauna change in response to environmental pressures.? The fact that the idea of species change was thought to be a revolutionary idea should catch you up straight. Humans have been modifying their plants and animals for millennia. There are two ears of corn on my kitchen counter right now that can be traced to a simple meso-American grass, teosinte, which was selectively grown over many hundreds if not thousands of years to produce what now fills most of the fields in Central New York. Take a look at the many breeds of dog, all of which are the descendants of wolves. Pekingese didn’t develop into lap dogs without human intervention.
The idea that living organisms changed their phenotype (what you see, hear, can touch, smell, taste,etc) because of pressure from the environment (including other flora and fauna, climate, etc) without human intervention was revelatory and also the source of much contention. Natural selection, the general terms used by Darwin to encapsulate all of the forces that instigate change, was and for some still is, wildly heretical. If you only read about the Scopes “Monkey Trial” or saw the movie “Inherit the Wind”, you would be aware of the dichotomy that arose between those who saw the idea of evolution as a denial of the bible vs. those who saw evolution as an explanation of scientific facts. The differences are still fodder for some rather spirited discussion.
Still, the two men in question, Lamark and Darwin, offered proof that evolution is a fact of life. How that occurred, outside the hand of man, separated the two. I should step back and note that Darwin had no proof of the mechanisms that drove evolution. No one was aware of genes or how they functioned. He even accepted the long-ridiculed theory offered by Lamark that evolution occurred because of acquired characteristics for a time. What is an acquired characteristic? If you are a blacksmith and use your right arm for work, it will develop greater strength than the left and according to Lamarck, that physical strength will be passed on to succeeding generations. Another often used example is that of the length of the neck of a giraffe. Lamark said that as the giraffe foraged for food in the trees, each generation grew a longer neck that was passed on to succeeding generations. He also said that disuse and the changes that grew from disuse could be passed on to future generations.
Gregor Mendel, an Austrian Monk, unknowingly discovered the basic mechanisms of inheritance and Watson and Crick, who were not monks, demonstrated how genes were made of four bases which wound around each other in a double helix. Voila … genes, or DNA, the blueprints of life told us how we were constructed and by changes in genes, how we change. By “WE”, I mean all living organisms.
Then came epigenetics, a discovery that the mechanisms that control the expression of DNA, the stuff that holds the blueprints of life, our genes, can be changed during the lifetime of an individual and that change, not in the genes, but in the chemistry (histones and methylation … I’ve spent a lot of time looking up these terms) surrounding them, can be passed on to succeeding generations.
The term epigenetics crept into a casual conversation on our porch one afternoon while we were discussing genealogy with a guy who has traced his family practically back to the Middle Ages and he, an artist, noted that many of his predecessors were also artists of sorts. Did he inherit a predilection to art? Is there more to epigenetics than a lot of looking up scientific terminology? Did he inherit his talent from his ancestors? Did the fact that most of my father’s Irish relatives identified themselves as tailors explain why my sister can recover a sofa or design and make and Irish dancing costume?
I can’t do either, so what did I inherit from my grandparents, my great grandparents? Well, both of my grandmothers and my paternal great grandmother would never have been called slim. Epigenetics might be the explanation of why I am forever on Weight Watchers.
My paternal grandparents passed before I was born, so seeking clues to other epigenetic inheritance had to be done among my father’s sisters and brothers. The were all musical. That would not be me either, although I love music as an afficianato. My brother … absolutely. He could play a tombone and a bass without lessons and front several bands when he was young. We had no trombones or bass fiddles hanging around our house. He had what seemed to be a natural proclivity for music.
As musical as they were, they all seemed to be able to hold dissonant views. For a group that were devote Catholics, they all had mystical leanings to fortune tellers and belief in reincarnation. I don’t frequent fortune tellers and believing that one of my cats is the reincarnation of another relative is a bit much for me, but I do have this idea that there is more to our relationships with the wider world, worlds that we cannot see .. and OK, I am not surrounding myself with crystals but there is something… Most of these things can attributed to where and with whom you grew up.
We come back to the question of nature vs. nurture. Epigenetics, as it now exists, tells us that inheritance is more complicated than we knew. Inheritance of things like immunity, susceptibility, etc., maybe even individual preferences are on the table. In the meantime, I am concerned about what I may be passing on to my grandchildren and their offspring. Will musical ability skip a generation? Will stray cats follow them home? And then, I did eat those Drake’s cupcakes, drink diet soda, stay up late to watch movies, get angry at people who were unkind to animals…I lose patience with those who aren’t patient. I am a grouch when I am tired. Are these traits going to be my contribution to my posterity?