Lecture 4 - Genes and flies
The best chance of Frankenstein understanding how genes control development comes from the study of the fruit fly because so much of its genetics is known. The genes appear as bands on its unusually large chromosomes and their activity can be seen directly when the larvae metamorphose into flies. The larva itself doesn't turn into a fly but carries the parts for the adult -the imaginal discs - like a DIY kit.
There is a remarkable group of genes (homeotic) which can change one structure into another. Instead of an antenna a leg may develop on the head. Flies with four wings (they cannot fly) can be constructed.
With a genetic trick one can make flies whose tissues have different genetic make-up - mosaics. This enables one to follow the development of a single cell and all its offspring. This leads to the discovery of compartments - groups of cells which will not cross an invisible line and which are under common genetic control.
The homeotic genes controlling the naming of the segments in the embryo have been isolated, and there is a small part - the homeobox - common to most of them, which codes for a protein. The coding region is highly conversed and is also found in man, mice, birds and worms. Is this the key to understanding development that Frankenstein is seeking?
About the 1986 CHRISTMAS LECTURES
In the 1986 CHRISTMAS LECTURES, Professor Lewis Wolpert (1929-2021) explores developmental biology in a series titled 'Frankenstein's Quest'. Quoting the fictional Dr Frankenstein: "After days and nights of incredible labour and fatigue, I succeeded in discovering the cause of generation and life..." These lectures will look at how life really is generated.
All life comes from cells and all the animals we see about us come from just one cell, the fertilized egg. How does the egg give rise to bats and boys, gnats and girls, eyes and arms? The egg divides and gives rise to many cells which move, multiply, change, and communicate, and from these activities animals emerge through embryonic development. Like an imaginary Frankenstein, we will explore what we need to know in order to control development in order to create not a monster, but an angel.