Drosophila melanogaster

Drosophila melanogaster (Black-bellied Dew-lover) a dipteran (two-winged) insect, is the species of fruit fly that is commonly used in genetic experiments; it is among the most important model organisms. In modern biological literature, it is often simply called Drosophila or (common) fruit fly. Students also nickname it Drozzy.

Development and embryogenesis

Main article: Drosophila embryogenesis

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Embryogenesis in Drosophila has been extensively studied, the small size, short generation time, and large brood size makes it ideal for genetic studies. It is also unique among model organisms in that cleavage occurs in a syncytium.

Related Topics:
Embryogenesis - Syncytium

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During oogenesis, cytoplasmic bridges connect the forming oocyte to nurse cells. Nutrients and developmental control molecules move from the nurse cells into the oocyte. In the figure to the left, the forming oocyte can be seen to be covered by follicular support cells.

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About 5000 nuclei accumulate in the unseparated cytoplasm of the oocyte before they migrate to the surface and are encompassed by plasma membranes to form cells surrounding the yolk sac. Early on, the germ line segregates from the somatic cells through the formation of pole cells at the posterior end of the embryo.

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Cell division in the early Drosophila embryo happens so quickly there are no proper checkpoints so mistakes may be made in division of the DNA. To get around this problem the nuclei which have made a mistake detatch from their centrosomes and fall into the centre of the embryo which will not form part of the fly.

Related Topics:
DNA - Centrosome

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