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I have read that mature red blood cells (MRBs)do not have DNA. So I am curious why crime scene technicians collect blood. Is it to collect and amplify segments of white blood cells?

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closed as off-topic by Charles, David, Amory, kmm, The Last Word Jan 22 '18 at 16:42

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Homework questions are off-topic on Biology unless you have shown your attempt at an answer. For more information see our homework policy." – Charles, David, Amory, kmm, The Last Word
If this question can be reworded to fit the rules in the help center, please edit the question.

  • $\begingroup$ A simple Google search of "DNA in blood" immediately provides an answer to the OP. VTC. $\endgroup$ – Charles Jan 14 '18 at 14:27
  • $\begingroup$ Blood was collected and analyzed long before DNA techniques. E.g. blood typing could rule out suspects with a different blood typing, or the blood on a suspect's clothing could be from an animal... $\endgroup$ – jamesqf Jan 14 '18 at 20:44
  • $\begingroup$ I appreciate the comments. Just to be clear, I wasn't being lazy when I made the question. Of course I could use a search engine. I've been exposed to this StackExchange for maybe two weeks, and I find the questions and the depth of knowledge that contributors bring with their answers to be amazing. I plan to make a Toastmaster's speech on aspects of DNA later this month. No one in the speech club knows anything about cell biology. I'm sure they will be surprise to learn that MRBC's do not have DNA. The input given to me was just what I hoped for! $\endgroup$ – Mike Jan 15 '18 at 0:28
  • $\begingroup$ three words; white blood cells. $\endgroup$ – John Jan 19 '18 at 6:54
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There's still white blood cells with DNA.

Some forensic blood tests are:

Conventional serological analysis:

  • Analysis of the proteins, enzymes, and antigens present in the blood, for general doctor tests: (black/white/drunk/stoned/heroin addict/polio vaccinated/hiv pos...)

Restriction Fragment Length Polymorphism (RFLP) DNA :

  • Direct analysis of certain DNA sequences present in the white blood cells. This method also usually requires a "large" sample size to obtain significant results.

Polymerase Chain Reaction (PCR) DNA :

  • Analysis of certain DNA sequences that have been copied multiple times to a detectable level.
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