mitochondrial DNA, Jack the Ripper

• In 2002, crime novelist Patricia Cornwell, in Portrait of a Killer: Jack the Ripper—Case Closed, maintained that Sickert was Jack the Ripper.^[38] A psychological motivation for Sickert was said to be a congenital anomaly of his penis.^[39] Cornwell purchased 31 of Sickert's paintings, and some in the art world have said that she destroyed one of them in a search for Sickert's DNA, but Cornwell denies having done this.^[38][39] Cornwell claimed she was able to scientifically prove that Mitochondrial DNA from one of more than 600 Ripper-letters sent to Scotland Yard and mitochondrial DNA from a letter written by Sickert belong to only one percent of the population.^[40]

In 2004, the Oxford Dictionary of National Biography, in its article on Sickert, dismissed any claim that he was Jack the Ripper as "fantasy".^[41]

粒線體DNA（英語：mitochondrial DNA，縮寫作mtDNA）指一些位於粒線體內的DNA，與一般位於細胞核內的DNA有不同的演化起源，可能是源自早期細菌。雖然現存生物體中絕大多數作用於粒線體的蛋白質，是由細胞核DNA所製造，但這些基因中有一些可能是源於細菌，並於演化過程中轉移到細胞核中。

Mitochondrial DNA (mtDNA or mDNA)[2] is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, adenosine triphosphate (ATP). Mitochondrial DNA is only a small portion of the DNA in a eukaryotic cell; most of the DNA can be found in the cell nucleus and, in plants and algae, also in the plastids, like chloroplasts.