After you die, these genes come to life + Was Darwin's idea right after all?

After you die, these genes come to life

EXCERPT: . . . Peter Noble, a former professor at the University of Alabama ... helped [to] discover that long-dormant genes can spring into action hours or even days after an organism dies. The idea that genes would activate after an organism’s death was unheard of, so the researchers wrote it off as a mistake with their instrumentation. But repeated tests, in fish and then in mice, continued to bear out the impossible: genes activating hours, or even days, after an organism died.

[...] The scientists’ findings were met with skepticism, until a group of researchers led by Roderic Guigó at Barcelona’s Centre for Genomic Regulation also found post-mortem gene activity, this time in humans. “We were saved when the group from the Barcelona genome institute covered the paper on humans, because they … proved the same thing,” says Noble. Guigó and his team were studying gene regulation by analyzing tissues from people who donated their bodies after death. Their work was already underway when Noble’s paper was published, so they weren’t surprised by his team’s findings. “It was more or less what we were seeing,” says Guigó.

[...] But while this discovery opens up new possibilities for medical science, the biggest question posed by the research—why some of our genes activate after we die—remains a mystery. Noble thinks clues may lie in the kinds of genes that are reanimating. Though none of the zombie genes seem to make any physical changes after death, many of them are related to activities that are normally closely regulated or inhibited. This includes the gene that tells cells to produce the beginnings of a spinal column — once you’ve already got a spine, you no longer need to grow a new one. Other genes that activate after death are related to cancers. Perhaps in the absence of other genes that normally inhibit them, these genes seize the opportunity to reactivate, like teens throwing a party when their parents are out of town. (MORE)

Darwin’s Ideas About How Life Arose on Earth May Be Right After All

EXCERPT: In a new book titled Assembling Life: How Can Life Begin on Earth and Other Habitable Planets, David Deamer from the University of California in Santa Cruz argues that the critical chemical reactions that led to life’s appearance on Earth required fresh water rather than seawater. [...] In other words, Charles Darwin’s notion of a “little warm pond” as the cradle of life may be true after all.

[...] Even if we can’t yet answer how life originated, it would help a lot to know what environmental conditions were necessary, because that would tell us where else to search in the solar system. If life begins more easily in deep oceans, we should explore the ice-covered oceans of Europa or Enceladus. If it originated in hydrothermal pools on land, as Deamer proposes, then continents are required, and life is more likely to have developed on Mars and perhaps Venus. If, in addition, strong tidal forces—which our own Moon must have exerted on our young Earth—are needed, then Earth may actually be the only planet in our Solar System where conditions were right for biology. (MORE)
The idea of genes that are only active during death raises some interesting questions.

1. What is 'death' exactly?

Breath ceasing or the heart ceasing beating? These are old historical criteria that aren't used any more, since heartbeats and breathing can be restored by CPR or whatever. "Brain death" defined as the flatline cessation of neural activity? That's a currently popular one. Of course the same potential recovery proviso applies there, if a way is found to reboot the brain.

I'm personally interested in cell biology, hence I'm inclined to define 'life' in terms of the physiology of cells. And many cells in a "dead" person's body are still physiologically active (and hence 'alive') for some time after cessation of higher organismic functions like breathing, heartbeat or brain function. That's why organ transplants from deceased donors are possible. It makes no sense to transplant a dead rotting organ into a living recipient, but if the organ is still physiologically alive and functional, then it does.

So I'm inclined to think that death is a gradual biological process where functions cease, from the 'top' down. Cellular physiology lasts a lot longer than higher organismic functions.

Hence it makes sense that genes are still expressing themselves in the cells of individuals undergoing this process.

2. I'll preface #2 by saying that I think that Noble's hypothesis is probably right, that it might just be the failure of epigenetic gene-silencing in cells that are themselves failing due to lack of circulation or whatever.

But... the question does suggest itself: Could there possibly be some evolutionary selective advantage in genes that only express themselves during death? At first glance one might be inclined to say 'no', since if the person is "dead" (embarked on the death-process), then it's hard to imagine what these genes' advantage to that individual could possibly be. And "dead" people don't pass on their genes.

But suppose that the genetic control mechanism that causes this exists earlier in life and can be passed on by younger sexually active people. And suppose that activating these zombie-genes during the death process might prevent some kind of dangerous decomposition of the corpse that might endanger living individuals around it by spreading disease or something. Populations whose corpses don't decompose dangerously might have a selective advantage over those whose corpses do.

It's all just speculation, but it's interesting.

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