The Ancient Technology Activation gene or ATA gene for short, is a specific gene expression present within the DNA of the Ancients that was used as a sort of "genetic key", so only their kind can operate their technology.
According to Dr. Carson Beckett, who discovered its existence, the ATA gene is always on, instructing various cells in the body to produce a series of proteins and enzymes that interact with the skin, the nervous system and the brain, allowing gene carriers to operate Ancient technology by thought alone. The gene itself may be artificial in origin - created by an early generation of Ancients and passed down since. As the gene was introduced into the human population through interbreeding with the Ancients, a small percentage of humans from Earth already have this gene. However, since nearly 10,000 years have gone by since the Ancients ascended, the gene is exceedingly rare among humans, and rarer still for those who possess it to have much proficiency in its use. The same is true of some humans born in the Pegasus galaxy.
The gene is stronger in some than it is in others; the stronger the gene, the greater the ease with which the user can operate Ancient technology. Ancient handheld medical scanners can detect and measure the strength of the gene. The Atlantis expedition uses a ranking system called "Chair Interface Aptitude" (or CIA) that ranks people with the ATA gene in the order of their ability to use the Ancient Control chair, the single most sophisticated piece of technology requiring the gene as well as the one most dependent on the user's mental aptitude. The highest ranked person in Atlantis is Lt. Colonel John Sheppard, followed by Dr. Carson Beckett. It seems likely that people with greater familiarity with the technology, such as those who have used a Repository of knowledge, also have a much easier time using it. Colonel Jack O'Neill (who has an extremely strong ATA-gene) was able to use a Control chair with no apparent effort while under the influence of the repository, but has a much harder time activating a Puddle Jumper when he is no longer under its effects. This is simply because he rarely uses devices that requires the gene. However, O'Neill possesses a strong version of the gene even without the Repository to help him: he was able to override the Kinahhi control over the Sheh-fet and was able to fly the Time Jumper better than anyone at Area 51 who had the gene, with Lt. Colonel Samantha Carter saying that while the people at Area 51 could barely get the Time Jumper off the ground, he could fly it with ease once he figured it out. Indeed, his alternate timeline counterpart displayed a similar ease with using the Time Jumper without having encountered any sort of Ancient technology before. This indicates that Sheppard, Beckett and O'Neill are the strongest known carriers of the gene. It is later discovered that this was not a coincidence: all three men are from the same ATA gene cluster, and are likely related within eight generations. (SGA: "Legacy: Homecoming")
Starting in 2004, the Atlantis expedition team began to employ in vivo retroviral gene therapy (using a deactivated mouse retrovirus) to artificially implant the gene in humans; however, only 47 to 48% of those who undergo the procedure are rewarded with the ATA gene, and even then it is not always permanent. It is not clear how high those given the therapy would rank in the CIA test, though it should be noted that the two highest ranking individuals are natural carriers. The first one inoculated was Dr. Rodney McKay, on whom the treatment was successful. It has since allowed him to further his research on Ancient technology and fly Ancient ships. (SG1: "Lost City, Part 2", "It's Good to Be King", SGA: "Rising", "Hide and Seek", "Enemy at the Gate")
Its later suggested that the proficiency of the gene wielder doesn't have to do with the strength of their gene, but rather their ability to let go in the interface. John Sheppard is extremely good at this, hence his greater use of the gene while he suggests that Jack O'Neill lacks the ability to let go so much, resulting in his lesser use of the gene.
Usage in Ancient technology
Much of the Ancients' technology requires the gene in order to use some or all of its functionality. The technology possesses sensors which can detect the gene in any human, usually through physical contact. However, not all Ancient technology uses it in the same way. Certain technologies only need to be "activated" by someone possessing the gene, after which they remain active and usable by anyone, gene carrier or not. An example of this would be the Long-range communication stones. Other technology requires constant mental input from the user, and thus the gene is necessary for this technology to be used at all. Control chairs and Puddle Jumpers, for example, use a neural interface that necessitates the presence of the gene.
Ancient technology which uses the gene is often very sensitive to mental stimulus. For Ancients, this is not a problem, but for humans, their lack of mental discipline combined with limited understanding of Ancient technology can result in negative reactions. When Dr. Rodney McKay tested an Ancient Personal shield emitter, he was unable to remove it due to his subconscious fear of danger, which the shield interpreted as a desire for it to stay active. The shield prevented him from eating or drinking, as it is a full-body shield. Dr. Elizabeth Weir tricked McKay into deactivating it by presenting a scenario in which the shield's continued presence would put him in danger. Similarly, Dr. Carson Beckett accidentally fired a Drone weapon when he was pressured into sitting in a Control chair by McKay despite being afraid of it, nearly shooting down a nearby helicopter (the only viable target for the drone in the area). (SG1: "Avalon, Part 2", SGA: "Rising", "Hide and Seek")
- Arxanti (Ancient descendants) (SG1: "The Cost of Honor")
- Chosen (Dalerans, Ancient descendants) (SGA: "The Chosen")
- Lt. General Jack O'Neill (SG1: "Lost City, Part 2")
- Lt. Colonel John Sheppard (SGA: "Rising")
- Dr. Carson Beckett (SGA: "Rising")
- Sgt. Markham (SGA: "Thirty-Eight Minutes")
- Dr. Miko Kusanagi (SGA: "The Gift")
- Joe Spencer (SG1: "Citizen Joe")
- Major Evan Lorne (SGA: "Condemned")
- Harmony (SGA: "Harmony")
- Harmony's mother (SGA: "Harmony")
- Flora (SGA: "Harmony")
- Mardola (SGA: "Harmony")
- Lord Protector (SGA: "The Tower")
- Mara (SGA: "The Tower")
- Tavius (SGA: "The Tower")
- Captain Hugh Griffin (SGA: "Grace Under Pressure")
- Dr. Carolyn Lam (Stargate SG-1: Moebius Squared)
- Dr. Eva Robinson (SGA: "Legacy: Homecoming")
- Dr. Peter Grodin (SGA: "Rising")
By Tau'ri gene therapy
- Dr. Rodney McKay (SGA: "Hide and Seek")
- Colonel Dillon Everett (SGA: "The Siege, Part 2")
- Some of Col Everett's troops (SGA: "The Siege, Part 2")
- Lt. Morrison (SGA: "Misbegotten")
- Otho (SGA: "The Tower")
- Marie (SGA: "Legacy: Homecoming")
- Lt. Colonel Melissa Hocken (SGA: "Allegiance")
Unsuccessful gene therapy
- Dr. Abrams (SGA: "The Defiant One")
- Lt. Lou Miller (SGA: "The Siege, Part 1")
- Lt. Edison (SGA: "Coup D'etat")
- Bolton (SGA: "Adrift")
- Captain Frank Levine (SGA: "The Ark")
- Although he was never specifically stated to possess the Ancient gene, Anubis was able to use Ancient technology due to his part-Ascended status despite being originally a Goa'uld.
- Like Anubis, Dr. Daniel Jackson may possess some variant of the gene given his Ascension, but he was never seen using Ancient technology save for when he used Merlin's Repository of Knowledge, which may have been programmed to allow for less restricted access, and was once even attacked by an Ancient defence system that apparently attacked those without the gene (Although it may have been that the system simply didn't recognise him as an Ancient but would still have allowed him to control technology). When he and Dr. Rodney McKay was abducted by the Vanir during their attempt to activate the Attero device, the Vanir only used McKay to activate the technology, but this could have been because of McKay's superior scientific knowledge rather than because Jackson lacked the Ancient gene; any references to McKay alone possessing the gene could be taken as an ignorant assumption rather than a proven fact. (SG1: "The Cost of Honor", "The Quest, Part 2", "The Shroud", SGA: "First Contact", "The Lost Tribe")
- Jacob Carter may have it given that the Dakara superweapon activated when he touched the console, but it may have just been in response to someone touching it. (SG1: "Reckoning, Part 2")
- Jonas Quinn may also possess Ancient Activation Gene, because once he managed to turn on the Ancient device which caused hallucinations among SGC base staff and part of Colorado state residents (in fact it allows people to see entities from another dimension). Although Samantha Carter presumed this could have happened with anyone's touch. (SG1: "Sight Unseen")
- After a Puddle Jumper is stolen during the Battle of M2S-445, McKay suggests that Human-Wraith Hybrid Michael Kenmore may have created his own version of the gene therapy to enable himself to use Ancient technology. While this is unconfirmed, Michael later displayed the ability to fly the stolen Puddle Jumper, indicating that this is possibly correct. (SGA: "Search and Rescue", "The Seed", "The Prodigal")
- Neeva Casol may have it as she was able to activate a long-range communication stone, which must at least be initialized for someone to use. Dr. Jennifer Keller's was initialized by someone else. (SGA: "Identity")
- Lt. Colonel John Sheppard apparently has a very strong form of the gene, and can operate Ancient technology almost instinctively. Lt. General Jack O'Neill also posses the gene at a strength equal to that of Lt. Colonel John Sheppard, given the ease with which he's been able to use Ancient technology he's come across. Lt. Colonel Samantha Carter even commented on this once, saying that while the scientists at Area 51 could barely get the Time Jumper off the ground, O'Neill could fly it easily, similar to Sheppard with Atlantis' Jumpers.
- It is possible the ATA Gene-produced proteins and enzymes cause the synaptic pathways in the nervous system to generate minute electromagnetic fields that signals Ancient technology to work. However, this has yet to be confirmed.
- In "Hot Zone", Dr. Radek Zelenka said that the gene therapy only works for 48% of recipients. However, later in "Irresistible" Beckett told Lucius Lavin that the success rate is 47%. The change in percentage could simply be due to results from subsequent recipients.
- In Stargate Atlantis: Legacy: Homecoming, it was stated that the gene therapy only works on those who already have a dormant form of the gene in their system, rather than simply granting it to them out of nothing; as a result, McKay and others do have an Ancient ancestor, but the gene was simply dormant in their systems until the therapy activated it.
- In Stargate SG-1: Moebius Squared, a third generation Ancient who returned from Atlantis told SG-1 that the survivors divided themselves into 7 settlements, which will later form the largest clusters of humans whom express the strongest presence of the ATA gene. 5 of the 7 settlements include Mishihase, Hokkaido, southern Britain, the Horn of Africa, south Gulf of Aden, Yucatán Peninsula, and the Bulgarian Black Sea coast.
- According to Dr. Nicholas Rush the Ancient starship Destiny predates the necessity of the ATA gene. (SGU: "Darkness")
- GateWorld's article on