A winged affair

Insects are the first to evolve flight appendages,he informs and unlike in birds,the flight in insects is indirect. Wings do not have any muscles; instead,movement of muscles in the dorsal thorax helps wings to flap. “In the fruitfly,Drosophila Melanogaster,wings are the flight appendages proper. It is now widely accepted that evolution at the level of a family of highly conserved (from insects to human) genes popularly known as Hox genes has led to the diversity in animal body plan that we see now,” informs this Ph D from Cambridge University,who has specialised in genetics and developmental biology. The fruitfly Drosophila melanogaster is one of the most studied genetic systems,according to Prof Shashidharan. “Many genetic pathways have been well-characterised in this organism and it is accessible to a variety of genetic manipulations. Not only that,a large number of genes are highly conserved between flies and humans. Several developmental events,pathways,cell and tissue organisation are similar between the two systems. Using Drosophila as a model system,we are addressing two fundamental questions in biology,namely: What is the mechanism by which various cells/tissues/organs are positioned in their respective places in our body? How are shape and size of different organs determined?” says Shashidharan.

Asserting that his current and future work also involves functional genomics,using Drosophilaas a genetic system to study human genes,develop fly models of human diseases and study application of the same in drug screening,he says,“We have generated several transgenic flies expressing different truncated and mutant versions of human APC (normally found in colon cancer patients) to study structure-function relationship of various biochemical domains and to further improve drug-screening efficiency. In addition,we are working to determine ‘mode-of-action’ of certain drugs and plant-based insecticides using Drosophila genetics,” he adds.

Appendage means
An additional or subsidiary part existing on or added to an external body part such as antennae,mouthparts (including mandibles,maxillae and maxillipeds),wings,elytra,gills,walking legs (pereiopods),swimming legs (pleopods),sexual organs (gonopods) and parts of the tail (uropods). Typically,each body segment carries one pair of appendages.