Saturday, July 02, 2011
Grandma was right about this too
As honest biologists explore genetics in new ways, they're finding that earlier generations were right about most things, while the post-1920 modernist and egalitarian consensus is wrong about most things.
Until recently, one exception to this vindication was the universal set of old 'superstitions' claiming that children are partly shaped by events the mother experiences before the baby's birth.
Now it turns out that the basic theme of Grandma's 'superstition' was right, though the specific connections of exact events to exact characteristics in the kid are fanciful.
This makes beautiful sense. Think of a flower opening when the plant starts to dry out: "This may be my last chance to spread genes while I'm alive, so I'd better spread them now." Similarly, the chromatin responds to stress by opening up normally unused parts of the genome, blooming a wider range of genes to be more adaptable in harder situations. ¶ 11:55 AM
Until recently, one exception to this vindication was the universal set of old 'superstitions' claiming that children are partly shaped by events the mother experiences before the baby's birth.
Now it turns out that the basic theme of Grandma's 'superstition' was right, though the specific connections of exact events to exact characteristics in the kid are fanciful.
Stress is thought to cause "epigenetic" changes that do not alter the sequence of DNA but leave chemical marks on genes that dictate how active they are. Previous studies have shown that if mice are stressed for two weeks after birth, their offspring will show signs of depression and anxiety, despite enjoying the usual levels of maternal care. And there is mounting evidence that common health problems including diabetes, obesity, mental illness and even fear could be the result of stress on parents and grandparents. . . .
Now, Shunsuke Ishii ... has shown that chemical or environmental stress detaches a protein called activating transcription factor 2 (ATF-2) from chromatin, the densely packed DNA that makes up chromosomes.
ATF-2 serves as a kind of zipper, keeping the chromatin tightly bound. Once it is detached, the chromatin structure physically opens up, enabling otherwise hidden genes to become active.
Crucially, the unzipped chromatin is inherited in all descendants of the original "stressed" cell. If the stressed cell is an egg or sperm, the altered chromatin will pass to all cells in any offspring.
This makes beautiful sense. Think of a flower opening when the plant starts to dry out: "This may be my last chance to spread genes while I'm alive, so I'd better spread them now." Similarly, the chromatin responds to stress by opening up normally unused parts of the genome, blooming a wider range of genes to be more adaptable in harder situations. ¶ 11:55 AM
