Genome complexity; epigenetics: Lamarck is back (Introduction)

by David Turell , Thursday, August 30, 2018, 00:58 (2279 days ago) @ Balance_Maintained

Peter Ward in a new book:

http://nautil.us/issue/63/horizons/why-the-earth-has-fewer-species-than-we-think

"More and more, biologists are discovering that organisms thought to be different species are, in fact, but one. A recent example is that the formerly accepted two species of giant North American mammoths (the Columbian mammoth and the woolly mammoth) were genetically the same but the two had phenotypes determined by environment.

"Epigenetics (or heritable epigenetics, or neo-Lamarckism) is a series of different processes that can cause evolutionary changes as well as dictate how organisms develop from a single fertilized egg (in the case of sexually reproducing organisms, at least) to what we look like as adults. Some say it’s just a minor tweak of already understood processes and that it’s of little importance in the broader scheme of evolutionary change or the past or even future history of life. But to others epigenetics, while still poorly understood, is potentially of far greater importance than mainstream evolutionary theory, and mainstream evolutionists have heretofore accepted that. To a few, its ongoing discovery is causing an unfolding scientific revolution. But the discoveries have not happened evenly among the many fields within what we call “biology.” The great breakthroughs have mainly been studies looking at cells, and the molecules within cells, including DNA and RNA and other aspects of genetics. But to date there has been little if any progress in tying epigenetic change to the many events evidenced by fossils and the fossil record."

Here’s where epigenetics differs from traditional Darwinian evolution:

"The second kind of epigenetic change causes unforeseen modification to an organism without altering the genetic coding for specific genes, but it also passes on these changes. It can cause change ranging from minor to profound, and can be heritable. “Lamarckian” change is where something encountered in its environment, and not necessarily expected in the life of an organism, causes chemical changes to the DNA through the addition of tiny molecules, or through a shape change of the scaffolding that holds the twisted DNA molecules in specific shapes. Other kinds of epigenetic change can also be caused by the actions of small RNA molecules responding to some kind of external environmental change. Peter Ward, “Why the Earth Has Fewer Species Than We Think”

DAvid: Comment: This fits Tony's idea about species.

Tony: It would explain point eggs...

If only an epigenetic change in DNA can do it.