Jack the Ripper Identified Through Mitochondrial DNA

The identity of Jack the Ripper may have finally been determined as one Aaron Kosminski, a sadomasochistic hairdresser living in Whitechapel at the time of the murders. 

A shawl, bought at auction by amateur sleuth Russell Edwards, is believed to have been taken from the 1888 crime scene of Catherine Eddowes' murder. 

Mr. Edwards enlisted the help of forensic scientists to have DNA extracted from the shawl. 

As the integrity of nuclear (genomic) DNA was long since compromised, mitochondrial DNA was used for identification.

To confirm the blood was that of Ms. Eddowes, they tracked down one of her descendants, collected samples and determined it was a match. 

While examining the shawl under uv light, traces of semen were also found. 

It was through the extraction of viable mitochondrial DNA from the semen and its subsequent match to a female descendant that Aaron Kosminski was identified as the man believed to be Jack the Ripper.

WHAT IS MITOCHONDRIAL DNA? 

Transmission electron micrograph showing mitochondria (M)

MITOCHONDRIA (the organelles within our cells where glucose is converted to usable energy), have their own genetic material, as well as the machinery to manufacture their own RNAs and proteins. 

Human Mitochondrial DNA 

MITOCHONDRIAL DNA forms closed circular molecules that contain 16,569 DNA base pairs, with each such molecule normally containing a full set of the mitochondrial genes.

Each human mitochondrion contains, on average, approximately 5 such DNA molecules, with the quantity ranging between 1 and 15.

Each human cell contains approximately 100 mitochondria, giving a total number of mitochondrial DNA molecules/human cell of approximately 500.



In humans, mitochondrial DNA is inherited only from the mother's egg. 

It is passed to both sons and daughters. But only the daughters will continue to pass it on down the familial line through subsequent generations. 

And because it changes very little as it is passed down the line, it is an excellent source for both ancestry tracing and, as in this case, identification.






SOURCES

http://chemistry.umeche.maine.edu/CHY431/MitoDNA.html

Satoh, M.; Kuroiwa, T. (1991). "Organization of multiple nucleoids and DNA molecules in mitochondria of a human cell". Experimental Cell Research 196 (1): 137–140. doi:10.1016/0014-4827(91)90467-9. PMID 1715276.

http://en.wikipedia.org/wiki/Jack_the_Ripper

http://en.wikipedia.org/wiki/Mitochondrion

Jack the Ripper Unmasked Daily Mail September 6, 2014

http://en.wikipedia.org/wiki/Human_mitochondrial_genetics

IMAGE CREDITS

"FromHellLetter" by Unknown (credited to Jack the Ripper) - Original in the Records of Metropolitan Police Service, National Archives, MEPO 3/142; this facsimile from http://www.casebook.org/ripper_letters/. Licensed under Public domain via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:FromHellLetter.jpg#mediaviewer/File:FromHellLetter.jpg

"Mitochondrial DNA en" by derivative work: Shanel (talk)Mitochondrial_DNA_de.svg: translation by Knopfkind; layout by jhc - Mitochondrial_DNA_de.svg. Licensed under Creative Commons Attribution-Share Alike 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Mitochondrial_DNA_en.svg#mediaviewer/File:Mitochondrial_DNA_en.svg

"Chondrocyte- calcium stain" by Robert M. Hunt - Own work. Licensed under Creative Commons Attribution-Share Alike 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Chondrocyte-_calcium_stain.jpg#mediaviewer/File:Chondrocyte-_calcium_stain.jpg