Metroid DNA refers to the DNA strand of Metroids in the advanced stages of their life cycle and an item in Metroid: Samus Returns. The areas on SR388 are blocked off by a toxic purple liquid, and to decrease the levels of the liquid so that Samus can safely access the next area, she must collect DNA from Metroids she kills and channel it into a Chozo Seal near the liquid. After killing each Metroid, Samus absorbs the DNA into her Power Suit, and then uploads it into the Seal using her Arm Cannon.
In Metroid II: Return of Samus, the next area was blocked off by the liquid until all Metroids in the current area were killed, which would instead initiate an earthquake, and thus Metroid DNA was never collected.
Samus Aran eventually has her genetic makeup altered with the injection of Metroid DNA into her body near the start of Metroid Fusion. She inherits the Metroid weakness to cold. It is unknown if this is the same "type" of DNA as what she collects in Samus Returns. This later becomes a liability during Metroid Dread, when the E.M.M.I. are hacked and ordered to forcibly extract Samus's Metroid DNA. After all E.M.M.I. are destroyed, Samus discovers she has inherited the Metroids' ability to siphon energy from creatures, which had previously been kept at bay by the Thoha portion of her Chozo DNA, but was activated when she was attacked by Raven Beak due to Metroids being programmed to react violently to Mawkin DNA, which she possessed. Her Metroid powers fully awaken when she defeats Raven Beak, culminating in her Power Suit mutating into a Metroid-like form that is later neutralized when she absorbs Quiet Robe's X Parasite.
- Current amount of Metroid DNA
- "Metroid DNA ([symbol of Metroid DNA]) can be obtained by defeating Metroids."
On-screen message when trying to deposit Metroid DNA without having any
"Metroid DNA data is required to unlock this seal. No Metroid DNA is detected."