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The dynamic interactions between cellular-molecular physiology and the environment - The unicellular state as the level of selection - epigenetics

Part 2 of 4
Published on October 20, 2016   10 min

A selection of talks on Cell Biology

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0:00
My name is John Torday. I'm a Professor of Evolutionary Medicine at UCLA. This is a lecture in a lecture series entitled "Evolutionary Physiology". This lecture is entitled "The Unicellular State as the Level of Selection-Epigenetics".
0:16
It had long been thought that epigenetic marks that are acquired during the life cycle by the ovaries and testes, DNA methylation, ubiquitination, phosphorylation, acetylation, ribosylation were erased during meiosis. It is now known that some of those marks are retained during meiosis and further tested for their functional fidelity, during embryogenesis and during the life cycle of the organism.
0:42
Inheritance of epigenetic marks can occur via the germline, shown on the right. Or via effects of the environment on hypothalamic DNA methylation affecting maternal behavior, being passed onto the next several generations.
0:57
For example, an odorant in the environment can methylate sperm cells causing a startle response in the offspring.
1:06
Similarly, it has been shown that a physiologic stress to the pregnant mother rat can be passed on transgenerationally due to epigenetic modification of both somatic and germ cells.
1:17
There are several ways in which epigenetic marks are generated to modify DNA readout. Methylation, acetylation, phosphorylation, and ubiquitination are all depicted in this slide.
1:30
Only about 3% of human genetic disease is Mendelian. Therefore, 97% of human genetic disease is epigenetic. Epigenetic inheritance affects the offspring, not the adults. The significance of this to evolution theory is that it represents Lamarckian inheritance.
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The dynamic interactions between cellular-molecular physiology and the environment - The unicellular state as the level of selection - epigenetics

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