From Joshua A. Krisch at The Scientist:
Ninety-six hours after 43 zebrafish were frozen to death and 48 hours after 20 mice had their necks snapped, specific cells within their bodies were still hard at work. Gene transcription continued apace, and occasionally increased, according to a study published today (January 25) in Royal Society Open Biology. Genes linked to embryonic development, stress, and cancer were among those increasingly transcribed into RNA, researchers at the University of Washington and their colleagues reported. The results suggest that organismal death is an orderly, predictable process, and could help forensic scientists pinpoint time of death, plus help explain why organs from recently deceased donors seem to be more prone to cancer.
“Death is a time-dependent process,” said coauthor Peter Noble, whose group studies the postmortem transcriptome and microbiome. “We define the window between the time of organismal death and the time when not all cells are dead as ‘the twilight of death,’” he explained. “We found that there was a successional pattern to this time—more or less waves of transcription abundances. The shutdown is not random, it’s step-wise.”
Most surprising to the team was that developmental genes necessary for embryogenesis, which are normally silenced in adulthood, appeared to increase in abundance throughout the “twilight of death” in both fish and mice. “It could be that the genome unwinds as DNA degrades through postmortem time, allowing access to sites that have been previously silenced,” Noble said. “But we don’t know.”More.
What theory predicted this? And what to make of it?
Follow UD News at Twitter!