Which of the following is not a potential source of DNA for forensic analysis:
Correct Answer: Red blood cells
Description: Ans: B (Red blood cells ) "Samples for DNA testing must contain nucleated cells e.g leucocytes, seminal fluids, brain, bone marrow, muscle, skin, dental pulp, hair with root sheath cells & dried stains"- Parikh 6th/7.8POTENTIAL SOURCE OF DNA FOR FORENSIC ANALYSISBlood is an excellent source of human DNA. DNA is present in white blood cells of humans, but not red blood cells which lack nuclei. A dime-sized spot of blood, approximately 50 pi in volume, is enough DNA for a typical VNTR analysis.DNA from sperm heads is usually the most important source of DNA evidence for sexual assault cases. Five pi of semen contains approximately the same amount of DNA as 50 pi ofblood. Special extraction methods are required to release DNA from sperm heads.Saliva contains cellular material. DNA can be extracted from bite marks, cigarette butts, postage stamps on envelopes, and envelope flaps for DNA analysis. In fact, the "Unabomber" was convicted partially on DNA evidence from a letter-bomb he mailed that did not explode.The hair follicle at the base of human hairs contains cellular material rich in DNA. In order to be used for DNA analysis, the hair must have been pulled from the body -- hairs that have been broken off do not contain DNA.Any body tissue that has not been degraded is a potential source of DNA.Bone is one of the best sources of DNA from decomposed human remains.Like bones, teeth can also be an excellent source of DNA, long after the rest of the body has decomposed.Urine itself does not contain DNA, but it may contain epithelial cells, which do contain DNA. Most healthy individuals, however, do not excrete epithelial cells in their urine.
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