Christopherscience

EDITED: I'm sorry, I've been taking liberties and taking for granted certain pieces of knowledge. So... You can affect the "epigenetics" of your genes... Epigenetics are things that are "above, on, over, nearby, upon; outer; besides, in addition to; among; attached to; or toward." the DNA - which can still affect gene expression. Say, for instance you're a woman; you have two X chromosomes, but you could survive with only one (like how a man can survive with only one)... Were you you express exactly double the genes of your X chromosome, then you would get sick. You don't need all those genes all the time, and if you had them on all the time, then you would be very unhealthy because you might be over producing some proteins and under-producing other proteins... So women have an epigenetic thing called a Barr Body - where the second X chromosome is, more or less, inactive (though recent research shows that x-inactivation is not as pronounced as once thought). Basically, the entire X chromosome is regulated (which affects phenotype - the "look" of an organism... for instance, in cats, fur pigment is on the "X" chromosome... a "tortoiseshell cat" is a phenotypic look that you can see because of x-inactivation, and only occurs in female cats... All of the pigment genes still exists in all of the cells of the cat - the x-inactivation is something that happens "above" the genes... the splotches of color on a tortoiseshell cat are because of the epigentics of the cat's Barr Body [inactive x-chromosome]... this is the most visible example of epigenetics, with the most genetic material [an entire chromosome] that I could think of). Epigenetics has a lot to do with how a gene gets expressed, not all genes are on all of the time. When you eat a piece of cake - you might up-regulate your insulin gene-expression. To express the insulin gene - it needs to get copied. To get copied it needs to be fairly accessible to the "copy machine" called a polymerase. Normally, your genes are packed in tight. You've got 3 billion base pairs and they take up a lot of room. To pack them in - there are things called histones - that are kind of like spools that the strings of DNA wind-up around. There are more proteins than just histones that spool your DNA, and, collectively, these DNA-associated proteins are called chromatin (not to be confused with chromosomes, which is the whole string, of the 46 "strings" of DNA packed into each of your cells [this is an oversimplification, and, if you want to split hairs, there is also DNA in your mitochondria, but just focus on the spools of thread for now]). So you've got these things that wind up your DNA and make your DNA's genes inaccessible... but you just ate cake and you need your insulin gene, and you need it now! So you unpack that DNA. There are proteins that unpack that DNA... and that's very important to epigenetics... You have all the genes that your mother passed down to you... but you might not have all of your genes unpacked in the same way as hers were... Some genes might be tightly coiled and too inaccessible for you to express them. But how your genes are packed and unpacked is subject to change (some changes are more permanent than spooling the thread... some changes are hard to change back, such as chemically modifying the DNA itself... this is typically done in your cells to switch off genes on a more permanent time-scale, for instance your neurons don't need muscle-specific proteins - so your neurons might methylate the "muscle growth factor" gene to shut it off.) In fact... you can affect some of the unpacking by certain nurturing events (like if you eat way too much cake your insulin unpacking system might get messed up by chance; when your mother, who didn't eat as much cake and has the same insulin gene as you, -she has a perfectly fine epigenetic system surrounding her insulin expression. While the genes are shared in this hypothetical - the epi-genes are different [DNA packing, methylation, miRNAs, etc]). Interestingly, The genes you get passed down to you are not a blank slate in epigenetic terms - the level of expression of genes (due to epigenetics) are passed down, too, to some degree (this is what biochemists informally call Lamarkian evolution - the idea that you, as a parent, can affect the genes of your children beyond the fact that you just give them your raw genes). You get some of your mom and dad's epigenetics in addition to their plain-ol' genetics. [/anchor][anchor=bbib3]You can't inherit, let's say, a broken bone from your dad, but there are things that you can inherit beyond genes (things affected by "nurture" or epigenetics). There are studies which shows that parental smoking (even if a man stopped smoking, but smoked as a teenager, for instance) can lead to heritable epigenetic shifts in their children (methylation of DNA is one kind of epigenetic factor that was studied... methylation affect the accessibility of a gene being copied) (Hillemacher et al., 2008 Pembrey et al., 2006 and Chong et al., 2007)... I can get you copies of the full texts if you want to read more than just the abstracts. So while you can't change the underlying genes - you may be able to affect how those genes are expressed; this is the intersection of nature and nurture on some level... Nurturing affects nature (to some degree), and vice versa. To some degree nurturing is heritable... though I don't know what the degree is (it's still being studied) - which is why I'd be curious to see what "unspooling" of a gene for a brain chemical called oxytocin occurs in abused mothers' epigenetics. Oxytocin is, colloquially, called the loyalty neurotransmitter. It's a hormone that is important in imprinting as a child. I believe there was a study done with blocking oxytocin in ducks - and it shut off the behavior of the ducks following their "mother" (I believe it was a wooden surrogate in the study). Oxytocin might be important in autism - I don't know. But I'd be curious to see... and since there is already a population that the experiment has been done on (by circumstance) - these people might teach us all something about the epigenetics of abuse and autism, and I think that would be good to know about. ... I hope that clarifies what I meant by putting nurturing in quotations, while referring to epigenetics. Epigenetics can be heritable, epigenetics is also affected by nurturing.

I'm sorry, I've been taking liberties and taking for granted certain pieces of knowledge. So... You can affect the "epigenetics" of your genes... Epigenetics are things that are "above, on, over, nearby, upon; outer; besides, in addition to; among; attached to; or toward." the DNA - which can still affect gene expression. Say, for instance you're a woman; you have two X chromosomes, but you could survive with only one (like how a man can survive with only one)... Were you you express exactly double the genes of your X chromosome, then you would be sick. You don't need all those genes all the time and if you had them on all the time, then you wouldn't be very healthy because you might be over producing some proteins and under-producing other proteins... So women have an epigenetic thing called a Barr Body - where the second X chromosome is, more or less, inactive (though recent research shows that x-inactivation is not as pronounced as once thought). Basically, the entire chromosome is regulated (which affects phenotype - the "look" of an organism... for instance, in cats fur pigment is on the "X" chromosome... a "tortoiseshell cat" is a phenotypic look that you can see because of x-inactivation... this is the most visible example of epigenetics, with the most genetic material that I could think of). Epigenetics has a lot to do with how a gene gets expressed, not all genes are on all of the time. When you eat a piece of cake - you might up-regulate your insulin gene-expression. To express the insulin gene it needs to get copied. To get copied it needs to be fairly accessible to the "copy machine" called a polymerase. Normally your genes are packed in tight. You've got 3 billion base pairs and they take up a lot of room. To pack them in - there are things called histones that are kind of like spools that the strings of DNA wind-up around. There are more proteins than just histones that spool your DNA, and, collectively, these DNA-associated proteins are called chromatin (not to be confused with chromosomes, which is the whole string, of the 46 "strings" of DNA packed into each of your cells [this is an oversimplification, and, if you want to split hairs, there is also DNA in your mitochondria, but just focus on the spools of thread for now]). So you've got these things that wind up your DNA and make your DNA's gene inaccessible... but you just ate cake and you need your insulin gene, and you need it now! So you unpack that DNA. There are proteins that unpack that DNA... and that's very important to epigenetics... Because you might have all the genes that your mother passed down to you... but you might not have all of your genes unpacked in the same way... In fact... you can affect some of the unpacking by certain nurturing events (like if you eat way too much cake you insulin unpacking system might get messed up, when your mother, who didn't eat as much cake and has the same insulin gene as you, -she has a perfectly fine epigenetic system surrounding her insulin expression). Interestingly, The genes you get passed down to you are not a blank slate. You get some of your mom and dad's epigenetics in addition to their plain-ol' genetics. So while you can't change the underlying genes - you may be able to affect how those genes are expressed; this is the intersection of nature and nurture on some level... Nurturing affects nature (to some degree), and vice versa. To some degree nurturing is heritable... though I don't know what the degree is - which is why I'd be curious to see what "unspooling" of a brain chemical called oxytocin occurs in abused mothers' epigenetics. Oxytocin is, colloquially, called the loyalty neurotransmitter. It's a hormone that is important in imprinting as a child. I believe there was a study done with blocking oxytocin in ducks - and it shut off the behavior of the ducks following their "mother" (I believe it was a wooden surrogate in the study). Oxytocin might be important in autism - I don't know. But I'd be curious to see... and since there is already a population that the experiment has been done on (by circumstance) - these people might teach us all something about the epigenetics of abuse and autism, and I think that would be good to know about. ... I hope that clarifies what I meant by putting nurturing in quotations, while referring to epigenetics. Epigenetics can be heritable, epigenetics is also affected by nurturing.

Epigenetics is heavily influenced by "nurture". Lamarckian evolution used to be cast off because people thought Darwinian evolution was the only kind of evolution... Now we know more about gene silencing (small interfering mircoRNAs, for instance, that can regulate ~30% of human genes) and chromatin packing, etc., and it turns out you could hypothetically affect your children's phenotype (however slightly) through your own actions, and even the actions of grandparents have an effect on their grandchildren. Nothing is purely nurture when one considers that we're biological systems. There is a continuum and we're still learning the scale of nature vs nurture. The fact that there is a strong correlation to previous abuse means autism is probably more on the nurture side - but the fact that it occurs in the "nurturing" of mothers means it appears to be heritable, which points to an epigenetic link (like smoking during the teen years, or being a mother in a polish famine in WW2, methylates HDACs, which re-pack DNA-protein chromatin structures or whatnot [still an emerging field of study, the discovery of miRNA is less than 20 years old, for instance, and there's a lot left to study]). I just think it'd be interesting to study the DNA packing of oxytocin precursour genes in these mothers and children. Beyond that - this is just another article that supports the "a person shouldn't abuse their kids" hypothesis.

That's fair - I'm no historian, I don't know what counted as abuse and what the delicate interplay of development and autism spectrum diseases (as well as environment) was. Were families less abusive in the past? I was under the impression that families used to be more cohesive and caring (but the dissolution of the family in recent times lead to harsher childhoods - despite less starvation and disease)... But again - I am not a historian. I'm just curious if there was a lamarkian evolution marked by epigenetic shifts in something like an HDAC that lead to autism because of the abuse.That would be a a good empirical study vs self reporting, I think, maybe. Also I don't know if this fits, but I have a sneaking suspicion that there might be a different form of abuse in the form of negligence - since I think with larger families (siblings that interact with other siblings) and fewer two parent bread-winners in the past - maybe that would mean more emotional "abuse" nowadays in the form of negligence...? But, again, this is pure conjecture.

It's never a good idea to infer causality from correlation. All I was was pointing out was that the epigenetic hypothesis might help explain the findings - to test this you'd have to do a study of the histones and methylation of different regions of the child's chromatin (which is doable, but it would be expensive). Lamarkian evolution, while not as pronounced as Darwinian evolution, has been shown to affect humans (I believe some of the earliest and strongest evidence was from studies from the polish famine during WWII, though, it's been two years since I took biochemistry of human disease at my alma mater). I suspect the girls who are abused have methylation/demethylation of their histones and such - it'd be interesting to measure it - I'd look at the genes that regulate oxytocin if I were to study it, since that might be a good starting point... But regardless of how it happens - it's still unfortunate, and a sign of the power of development. If that accounts for a rise in autism in government data - I don't know, maybe. Whatever the case this seems to be proof that someone abusing children not only hobbles those children, but also their children's children.

Study: Women Abused As Kids More Likely To Have Children With Autism: http://healthland.time.com/2013/03/21/study-women-abused-as-kids-are-more-likely-to-have-children-with-autism/ Methinks epigenetics is at play here.