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How Dad's Stresses Get Passed Along To Offspring (scientificamerican.com)
An anonymous reader quotes a report from Scientific American: A stressed-out and traumatized father can leave scars in his children. New research suggests this happens because sperm "learn" paternal experiences via a mysterious mode of intercellular communication in which small blebs break off one cell and fuse with another. Carrying proteins, lipids and nucleic acids, these particles ejected from a cell act like a postal system that extends to all parts of the body, releasing little packages known as extracellular vesicles. Their contents seem carefully chosen. "The cargo inside the vesicle determines not just where it came from but where it's going and what it's doing when it gets there," says Tracy Bale, a neurobiologist at the University of Maryland School of Medicine. To probe the inheritance of such changes at the cellular level, Bale and co-workers performed a series of mouse experiments.
In one set of experiments [Jennifer Chan, a former PhD student that was part of the study] stressed a group of male mice, let them mate and looked at stress responses in the pups. The clincher was a set of in vitro fertilization -- like experiments in which she collected sperm from a male mouse that had never experienced induced stress. Half his sperm went into a lab dish with vesicles previously exposed to stress hormones. The other half was cultured with vesicles that had no contact with stress hormones. Chan injected sperm cells from each batch into eggs from a non-stressed female, then implanted the fertilized eggs -- zygotes -- into the same foster mom. The pups from non-stressed zygotes developed normally. Pups from stress-exposed zygotes, however, showed the same abnormal stress response as those whose dads had experienced stress before mating. That showed extracellular vesicles act as the conduit for transmitting paternal stress signals to the offspring, Chan says.
In one set of experiments [Jennifer Chan, a former PhD student that was part of the study] stressed a group of male mice, let them mate and looked at stress responses in the pups. The clincher was a set of in vitro fertilization -- like experiments in which she collected sperm from a male mouse that had never experienced induced stress. Half his sperm went into a lab dish with vesicles previously exposed to stress hormones. The other half was cultured with vesicles that had no contact with stress hormones. Chan injected sperm cells from each batch into eggs from a non-stressed female, then implanted the fertilized eggs -- zygotes -- into the same foster mom. The pups from non-stressed zygotes developed normally. Pups from stress-exposed zygotes, however, showed the same abnormal stress response as those whose dads had experienced stress before mating. That showed extracellular vesicles act as the conduit for transmitting paternal stress signals to the offspring, Chan says.
Lamarck is wrong and epigenetic does not salvage Lamarck in any way. What Darwin's Theory is not about is where sources of variation come from, but how they persist. Epigenetic traits do not last more than a few generations and cannot contribute to speciation. It is still the genes that are selected on.
The rest of what you write is just dribble. Part obvious - raise children well, who would have thought - and part nonsense, "therefore epi-genetics and evolution".
Those who do not learn from commit history are doomed to regress it.
You make it sound as if this is the full explanation for how homosexuality occurs. It's far more complicated than that. For instance, with each subsequent son a woman gives birth to, the likelihood of that son being gay goes up. To the point that a 14th son has a 50% chance of being gay. That's postulated to be the mother's immune system learning to clear out androgens and the cells that produce them.
Another confounding factor is that women who have 2 or more gay brothers have more offspring than women with only straight brothers. Which directly contradicts your postulate that a "pause in further offspring" is somehow the justification for homosexuality resulting from parental stress.
Implied in your post is the thought that homosexuality is an undesirable condition that would go away if "things were perfect". You forget that the higher a person's IQ is, the more likely they are to be gay or bisexual. The more creative a person is, the more likely they are to be gay or bi also. Gee, maybe there is more value to gays than just "they don't reproduce" or even "they stick around & help raise their sister's kids" (another theory trying to explain gays in Darwinian terms without considering them to have any value beyond their sexual actions.)
You are trying to use science to excuse your culturally induced prejudices.
On the one hand you take life too seriously, and on the other, you do not take playful existence seriously enough. Seth
So can this account for why hysterical drama queen parents have hysterical, drama queen children?
That might account for the growth of the Leftist population.