Touch DNA can last up to 2 weeks outside and 6 weeks or longer inside.
This duration is influenced by several factors:
- Environmental Conditions: Sunlight, temperature, humidity, and other environmental factors affect the degradation rate of DNA.
- Surface Type: The type of surface onto which the DNA is deposited influences its persistence. Porous surfaces may absorb DNA, protecting it to some extent, while smooth surfaces may lead to faster degradation.
- Amount of DNA: The initial amount of DNA deposited (i.e., how much "touch" occurred) impacts how long it's detectable. More DNA generally lasts longer.
- Human Factors: Handling, cleaning, and exposure to chemicals can all degrade or remove DNA.
Therefore, the exact longevity of touch DNA is highly variable and context-dependent. While detectable DNA can persist for the periods mentioned above, it's not guaranteed.
