Yes, but not all parts of the hair contain the same type or amount of DNA. The answer depends on which part of the hair you're referring to.
Where is DNA Found in Hair?
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Hair Follicle: The hair follicle, located at the base of the hair where it emerges from the skin, contains both nuclear DNA (nDNA) and mitochondrial DNA (mtDNA). nDNA provides a complete genetic profile, while mtDNA offers a more limited profile, inherited only from the mother. This makes the hair follicle an ideal source for DNA testing.
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Hair Shaft: The hair shaft itself (the visible part of the hair) typically contains only mitochondrial DNA (mtDNA), and often a very small amount at that. Nuclear DNA, the preferred source for identification, is usually absent or significantly degraded in the hair shaft. While some methods can extract nuclear DNA from hair shafts, the amount is often limited and may be too degraded for reliable analysis. The success of this extraction depends on several factors, including the age of the hair and the preservation techniques used.
Several sources confirm this nuanced relationship between hair and DNA: One study highlights that while hair shafts are an important source of DNA in forensics, only a low amount is typically present [Efficient DNA extraction from hair shafts - ScienceDirect]. Another source clarifies that the hair root (part of the follicle) contains the DNA, while the hair shaft itself generally does not [TIL that when they test DNA from hair, they actually analyse the root ... - Reddit]. Other sources further emphasize that nuclear DNA is primarily found in the hair root, and extracting usable nuclear DNA from the shaft is challenging and often unsuccessful [No Nuclear DNA in Rootless Hair: Myth or Fact? - ISHI News], [Does hair contain DNA? - Quora], [Why This Scientist Keeps Receiving Packages of Serial Killers' Hair ... - New York Times].
In summary, while DNA can be found in hair, its presence and type vary considerably depending on the hair's part. The hair follicle is the primary source of readily-usable DNA, while the shaft's DNA content is typically limited and difficult to extract and analyze reliably for a full genetic profile.
