DNA
Deoxyribonucleic acid, or DNA, is the building block of most carbon-based lifeforms. It is the blueprint for a living organism and encodes amino acids for polypeptides which form proteins, which, when properly sequenced, form ular pathways that together form the physical structure and anatomical characteristics of an organic lifeform. If DNA is changed in some way, the host organism responds to the change by re-making itself in the form specified by the new DNA, often extremely rapidly. 

DNA samples were collected from all Vulcan children at birth and kept on file by the Vulcan government. ()

By matching DNA gene types, Starfleet was able to identify Jono as Jeremiah Rossa. ()

According to Geordi La Forge, over a hundred years of testing had proven that use of the transporter had no effect on DNA. ()

In 2256, Klingons harvested Lieutenant Ash Tyler's DNA in order to reconstruct his consciousness and rebuild his memory in preparation for grafting with Voq's psyche in the choH'a'. ()

During the mid-23rd century, Harcourt Fenton Mudd created androids thinly skinned with replicant DNA, which appeared to be him to scanners. ()

In the mid-2250s, Captain Maddox injected Barlow with the DNA of the Comtaxan parasite, which was known to not "mix well" with Human DNA. The injection resulted in the brutal vaporization of Barlow. ()

In 2367, Ishara Yar offered to have her DNA tested as a means of proving that she was Lieutenant Natasha Yar's sister. The test was administered by Doctor Beverly Crusher and proved that her claim was true. ()

In 2369, when Lieutenant Reginald Barclay was exposed to a high-energy plasma field in a transporter field, Dr. Crusher wanted to examine him using a base pair correlation to see if there was any sign of breakdown in his DNA. () 

Also in 2369, Dr. Crusher investigated the cause of the age reversion of four crew members. She explained that unlike DNA, which never changed, RVN (rybo-viroxic-nucleic) took on additional varoxic sequences during puberty. ()

That same year, following clues developed by his mentor, Professor , Jean-Luc Picard discovered evidence that an ancient race of humanoids had seeded many planets with their DNA billions of years earlier. The evidence suggested that Humans, Romulans, Klingons, Cardassians, and others may have had far more in common than previously believed. ()

Changelings had DNA in their morphogenic matrix. In 2369, Constable Odo noted that traces of his DNA had been left at the scene of Ibudan's murder on Deep Space 9, intended to aid in framing him for the crime. ()

In 2370, a DNA test established that Rugal was the son of Kotan Pa'Dar. ()

The counter-insurgency program on Deep Space 9 employed a DNA scan to verify the identity of Gul Dukat, preventing Elim Garak from posing as him. ()

DNA extracted from a male could be used to impregnate a female. In 2372, Seska claimed she impregnated herself with DNA she had stolen from Commander Chakotay while he was her prisoner. ()

The missile Cardassian ATR-4107 ("Dreadnought") used a DNA scan on anyone visiting it to establish their identity. ()

Each cell of the DNA of a member of Species 8472 contained more than one hundred times the DNA of a Human cell, making them the most densely coded lifeform that The Doctor had ever seen. ()

In 2374, certain segments of the DNA of a number of  crew were hyper-stimulated as part of the experiments by the Srivani, resulting in dangerous mutations. ()

The DNA and psychological profile of Alpha Jem'Hadar were specifically designed for combat in the Alpha Quadrant. ()

In 2375, Commander Valerie Archer (secretly a member of Species 8472 in disguise) shared a kiss with Commander Chakotay to obtain his DNA, which she was then able to analyze to prove that he was Human. ()

In 2399, Commander William T. Riker stated to ex-Admiral Jean-Luc Picard "The kid's got Data in her DNA," regarding the android Soji Asha. The statement was metaphorical, as artificial lifeforms such as androids did not have DNA. ()

The Kobali used an extensive process that involved altering DNA of the dead from other races to create new members of their species. ()

A strand of DNA, presumably from an Earth species was seen in the resetting time stream after the end of the Temporal Cold War. ()

Background information 
As DNA research was relatively new in the 1960s (DNA structure was first established in 1953, with the first notable DNA sequencing research conducted in 1973),  has no mention of this rather significant piece of medical science, even though DNA would have been well known in the 2260s according to Star Trek canon. It is also for this reason that The Original Series episodes depended on other medical methods, whereas DNA samples would have been the preferred choice. Such examples include the voice print identification of Kodos, seen in , and a reference to "medical plates" during the examination of Peter Kirk in . By the time  started airing, DNA was a familiar-enough concept to the Star Trek audience that the show's creators felt it was acceptable for the series to refer to DNA. (Trek: Deepspace Nine, p. 55)

See also 
 Base pair
 Base pair correlation
 Base pair destabilizer
 Base pair sequencer
 Chromosome
 DNA acquisition sensor
 DNA code analyzer
 DNA probe
 DNA profile
 DNA reference scan
 DNA sequence
 DNA sequencing
 DNA sequencer
 DNA resequencing
 Deoxyribose suspension
 Gene
 Gene splicing
 Intron
 RNA
 mitochondrial DNA
 Selected DNA exchange

External link 
 

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Biochemical compounds