The internal reproductive organs of a male Anopheles gambiae transgenic mosquito. The male accessory glands (M), in which seminal secretions containing proteins and peptides are produced, and the testes (T), where sperm cells develop, are indicated. The image is an overlay of a fluorescent and a transmission microphotograph. The fluorescence in the testes is derived from the expression of a green fluorescent protein egfp reporter gene driven by the testis-specific β2-tubulin promoter . The scale bar is indicated.