Thanatotranscriptome

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DNA microarray used to analyze the expression of human (left) and mouse genes. Affymetrix-microarray.jpg
DNA microarray used to analyze the expression of human (left) and mouse genes.

The thanatotranscriptome denotes all RNA transcripts produced from the portions of the genome still active or awakened in the internal organs of a body following its death. It is relevant to the study of the biochemistry, microbiology, and biophysics of thanatology, in particular within forensic science. Some genes may continue to be expressed in cells for up to 48 hours after death, producing new mRNA. Certain genes that are generally inhibited since the end of fetal development may be expressed again at this time. [1] [2] [3]

Contents

Scientific history

Clues to the existence of a post-mortem transcriptome existed at least since the beginning of the 21st century, [4] 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, [2] 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. [5]

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. [1] [3] 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.

Thanatotranscriptomic analysis

Characterization and quantification of the transcriptome in a given "dead" tissue can identify genetic assets, which can be used to determine the regulatory mechanisms and set networks of gene expression.

The techniques commonly used for simultaneously measuring the concentration of a large number of different types of mRNA include microarrays and high-throughput sequencing via RNA-Seq.

Analysis from a serology postmortem can characterize the transcriptome of a particular tissue cell type, or compare the transcriptomes between various experimental conditions. Such analysis can be complementary to the analysis of thanatomicrobiome to better understand the process of transformation of the necromass in the hours and days following death. [6]

Applications

Future applications of this information could include:

See also

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References

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