Sidestep: DNA from hair?
If we decide not to take bones samples it will be because there is something else available, something that provides access to DNA with the least disturbance - hair samples!
Typically, only the hair root in the hair follicle contains nuclear material suitable for DNA testing. The shaft contains abundant mitochondrial DNA. Nuclear DNA is best. So, if one rips out a hair from the scalp, some follicular tissue may be attached containing nuclear DNA.
If hair is available (which is should be because the cave is a sealed dry cave), then all we need are to pluck some samples that include the part from below the surface of the skin. Hair that is cut or shed does not unfortunately contain any nuclear DNA. For hair DNA testing to be successful the hairs must have the hair follicle attached. Hair DNA testing with freshly plucked hair is of course always better and a minimum of 5 hairs is recommended. If the hair is very old, one can opt to use advanced testing methods but these will come at an added, extra cost. Nevertheless, whether the hair is old or freshly plucked, you can still conduct your hair DNA test. Of course tue unknown is can you test a 1400 year old hair sample?
They need to be collected without contamination to ensure accuracy when sent or laboratory analysis. With hair DNA testing other than to carry out an MtDNA test, the success rate is 75%; thus, if the hairs contain the follicle, laboratories have a fairly high chance of extracting the necessary, undegraded DNA to conduct the test.
Challenges occur because people often assume hair samples make ideal samples for DNA testing. Whilst hair samples can be accurately used for the testing it depends very much on the part of the hair at hand. here we explain it in more detail. The hair fibers (sometimes referred to as the hair shaft) are actually formed by keratinocytes, types of skin cells which are responsible for the synthesis of the protein keratin. These cells naturally die and in the process get converted from cells into a horny, tough material such as hairs. This conversion process is known as cornification, and it involves the destruction and degradation of the cell nucleus (and thus, also of the genetic material enclosed within). As a consequence of cornification, the hair shaft, which is the part of the hair that protrudes out of the scalp, does not contain any nuclear DNA. Even when hairs do have the hair roots, the probability of successful extraction of a complete DNA profile using standard PCR technology is somewhere between 60-70%.
The success rate of hair samples is dependent on a number of factors: the age of the sample, the way the sample has been collected and stored, and any external forces that may have altered the state of the DNA.
New test breakthrough: Just recently, US government scientists say a new method of analysing genetic mutations in proteins in human hair could lead to the first forensic technique other than DNA profiling that could reliably match biological evidence to a single person with scientific precision. US Energy Department researchers at Lawrence Livermore National Laboratory in California said their early study - using hairs recovered from 76 living people and six sets of skeletal remains from London dating to the 1750s - shows the promise of hair “proteomics”, or the study of proteins that genes produce.
