Abstract:

Objective   To determinate the genome size of demodex by flow cytometry(FCM), which could lay the foundation for the construction of gene bank and the screening of functional genes of demodex. Methods   Clean mites washed with cleanser essence and selected under microscope were collected. After smashing the mites by combination of tissue grinder and ultrasonic wave, mites’ nuclei were extracted in citric acid solution. Chicken erythrocytes were served as an internal reference. The mixed sample of demodex and chicken erythrocytes was dyed by propidium iodide (PI). The peak values of the sample fluorescence intensities were measured by FCM. Comparing the multiple relationships between the two peak values, mites’ genome size was calculated. Results   The DNA content of demodex was about 1.05pg/2C determinated by FCM. 1pg converts to 978Mb, so the mite’s genome size was the equal of 512Mb. Conclusion   Flow cytometry could rapidly and accurately determinate the genome size of Demodex, which was the foundation work for the research of mite’s genomics.

Key words: Demodex; Genome size; Genomics; PI dyeing; Flow cytometry