Clues to the existence of a post-mortem transcriptome existed at least since the beginning of the 21st century,  but the word thanatotranscriptome (from (thanatos-, Greek for "death") seems to have been first used in the scientific literature by Javan et al. in 2015, following the introduction of the concept of the human thanatomicrobiome in 2014 at the 66th Annual Meeting of the American Academy of Forensic Sciences in Seattle, Washington.
In 2016, researchers at the University of Washington confirmed that up to 2 days (48 hours) after the death of mice and zebrafish, many genes still functioned. Changes in the quantities of mRNA in the bodies of the dead animals proved that hundreds of genes with very different functions awoke just after death. The researchers detected 548 genes that awoke after death in zebrafish and 515 in laboratory mice. Among these were genes involved in development of the organism, including genes that are normally activated only in utero or in ovo (in the egg) during fetal development.
The thanatomicrobiome is characterized by a diverse assortment of microorganisms located in internal organs (brain, heart, liver, and spleen) and blood samples collected after a human dies. It is defined as the microbial community of internal body sites, created by a successional process whereby trillions of microorganisms populate, proliferate, and/or die within the dead body, resulting in temporal modifications in the community composition over time.