DNA testing.

Immature RBC's do have a nucleus while they're in the marrow, but lose it before they move into circulation. So what you say is correct for DNA testing purposes.

Definitely not a stupid question!

This is absolutely not a stupid question, I am looking forward to the responses because I know absolutely nothing about this subject. Thanks for a great question.

Ally: Blood contains RBC's and WBC's...white blood cells (WBC's) do contain DNA.

Blood is the most commonly used source of DNA for testing. Blood should be collected in a purple top tube or one containing EDTA preservative which inhibits DNA degradation during shipment. A few labs now accept blood spotted onto filter paper. Blood may be refrigerated but many labs ask that it not be frozen because this lyses all the cells and only white blood cells contain DNA in mammals. The first generation of parentage testing was based on blood typing (blood groups and protein polymorphisms), using a series of reliable, low-cost and technologically simple testing routines, now provided by laboratories worldwide. While these tests have been highly effective in providing solutions to paternity questions and sorting out switched foal scenarios, three limitations have occasionally, but repeatedly, provided frustrations. First, the tests can only be performed with fresh blood, thus excluding the possibility to use other kinds of samples, especially those that might be available from dead. Second, the requirement of a blood sample may necessitate the assistance (and expense) of a specialist, special shipping containers, handling conditions and difficulties in the international transport of samples. Third, if a solution could not be obtained from the available blood typing tests, no other effective tests were available to extend the test battery.