Oliver Rando and epigenetic inheritance
Oliver Rando came by to talk at another theory lunch. It was hard for me to follow this one, but I understood a bit of it.
He talked about epigenetic inheritance, which refers to traits that are inherited by a cell's offspring but are not part of the DNA. Although our cells all have the same DNA, or genotype, they express this genotype in different ways, called the phenotype. I had thought that only DNA is inherited when a cell reproduces, but of course some non-DNA must be inherited so that the phenotype is transmitted. Liver cells, for example, generate more liver cells; they don't generate skin cells. Liver and skin cells have the same DNA, so something else must be transmitted to the offspring to keep them the same phenotype as the parents.
A change in the epigenetically inherited stuff causes changes in the type of cell. These changes occur due to mutation, but sometimes they seem intentional; part of a larger adaptation system. An organism might occasionally switch to a different phenotype, perhaps to see if the new phenotype will have a better chance of surviving in a given environment. And this might happen more often when the organism is under stress, in other words, not adapting well to its environment.
He talked about epigenetic inheritance, which refers to traits that are inherited by a cell's offspring but are not part of the DNA. Although our cells all have the same DNA, or genotype, they express this genotype in different ways, called the phenotype. I had thought that only DNA is inherited when a cell reproduces, but of course some non-DNA must be inherited so that the phenotype is transmitted. Liver cells, for example, generate more liver cells; they don't generate skin cells. Liver and skin cells have the same DNA, so something else must be transmitted to the offspring to keep them the same phenotype as the parents.
A change in the epigenetically inherited stuff causes changes in the type of cell. These changes occur due to mutation, but sometimes they seem intentional; part of a larger adaptation system. An organism might occasionally switch to a different phenotype, perhaps to see if the new phenotype will have a better chance of surviving in a given environment. And this might happen more often when the organism is under stress, in other words, not adapting well to its environment.
