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Forensic entomology contains three aspects: medicocriminal entomology, urban entomology, and stored product entomology. This article focuses more on the medicocriminal aspect and how DNA is analyzed with various blood feeding insects. == Blood meal extraction == To extract a blood meal from the abdomen of an insect to isolate and analyze DNA, the insect must first be killed by placing it in 96% ethanol. The killed insect can be stored at -20°C until analysis. When it is time for analysis, the DNA must then be extracted by dissecting the posterior end of the abdomen and collecting 25 mg of tissue. The cut in the abdomen should be made with a razor blade as close to the posterior as possible to avoid the stomach.〔Pizarro, Juan et al. “A method for the identification of guinea pig blood meal in the Changas disease vector, Triatoma infestans” in Kinrtoplastid Biol Dis., V. 6, 2007.〕 Using a DNA extraction kit, the DNA is extracted from the tissue. If the DNA is mixed with samples from more than one individual, it is separated using a species specific primer. Once extracted and isolated, the DNA sample goes through a polymerase chain reaction (PCR), is amplified and identified. PCR works by analyzing species specific mitochondrial DNA. PCR is currently the most commonly used method of species identification. This results from the fact that it is very sensitive in that it requires only a small amount of biological material, and can also utilize material that is not particularly fresh. The sample can be frozen and stored while still remaining usable for later PCR. DNA requires one hour to reach the abdomen of an insect, so DNA can be amplified one to forty-four hours after an insect feeds. Some research suggests that the source of a blood meal can be determined up to two months post feeding. To amplify DNA, it must first be denatured by exposing it to a 95°C temperature for one minute, followed by thirty cycles of thirty-second 95°C exposures. Then denatured DNA is mixed with a specific primer. A chromatograph is conducted on 2% agarose gel, stained, and viewed with UV fluorescence. The DNA is identified by looking for genome specific repetitive elements and by comparing it with known examples. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Use of DNA in forensic entomology」の詳細全文を読む スポンサード リンク
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