Dear Sciforumers,
as you might have read in another thread I recently was at a meeting on developmental biology and why not share my thoughts and experiences with you. After all, not everybody gets the chance to attend scientific meetings.
There was a very nice talk at this meeting by Susan Mango. She is quite a famous researcher in our field. She talked about several subjects, but one I found most interesting and that was 'combinatorial control'.
Combinatorial control deals with the problem of gene regulation. As you might realize it is essential that specific genes are switched on and off at specific moments during development. The expression of a gene at the wrong time or wrong place, or both can be disastrous for the developing embryo!
We all might have heard that a region of the DNA just before the actual gene regulates gene expression, and is called the ‘promotor’. On this promotor region DNA binding proteins can bind and actually determine if the gene is active or not. That is all old stuff.
And then came the idea of ‘control by combinatorial codes’ from the Drosophila field. The number of signalling pathways that actually regulate gene expression is tiny compared to the amount of different cell types. So how can these more or less general signals be translated into quite specific gene expression patterns? The idea of combinatorial codes is that gene expression regulation acts as some kind of computer where the quantity (amount of binding sites, amount of activators compared to repressors) and quality (strength of binding sites and activators and repressors) is sensed and calculated.
Short review: Nature (2000) vol 418, page 419-420
Susan Mango had another interesting twist on this idea that they actually had some algorithms looking for these short control elements in the DNA to which the regulators bind. They also noticed that by changing the DNA code of these elements slightly, for instance changing one nucleotide, the expression pattern of the target gene changed in time or location, or both.
Basically this is how evolution could manage to make chances fast. Genes do not change, but the promotor elements do, which has consequences for the temporal and spatial locations of certain genes, which can then influence shape and morphology.
as you might have read in another thread I recently was at a meeting on developmental biology and why not share my thoughts and experiences with you. After all, not everybody gets the chance to attend scientific meetings.
There was a very nice talk at this meeting by Susan Mango. She is quite a famous researcher in our field. She talked about several subjects, but one I found most interesting and that was 'combinatorial control'.
Combinatorial control deals with the problem of gene regulation. As you might realize it is essential that specific genes are switched on and off at specific moments during development. The expression of a gene at the wrong time or wrong place, or both can be disastrous for the developing embryo!
We all might have heard that a region of the DNA just before the actual gene regulates gene expression, and is called the ‘promotor’. On this promotor region DNA binding proteins can bind and actually determine if the gene is active or not. That is all old stuff.
And then came the idea of ‘control by combinatorial codes’ from the Drosophila field. The number of signalling pathways that actually regulate gene expression is tiny compared to the amount of different cell types. So how can these more or less general signals be translated into quite specific gene expression patterns? The idea of combinatorial codes is that gene expression regulation acts as some kind of computer where the quantity (amount of binding sites, amount of activators compared to repressors) and quality (strength of binding sites and activators and repressors) is sensed and calculated.
Short review: Nature (2000) vol 418, page 419-420
Susan Mango had another interesting twist on this idea that they actually had some algorithms looking for these short control elements in the DNA to which the regulators bind. They also noticed that by changing the DNA code of these elements slightly, for instance changing one nucleotide, the expression pattern of the target gene changed in time or location, or both.
Basically this is how evolution could manage to make chances fast. Genes do not change, but the promotor elements do, which has consequences for the temporal and spatial locations of certain genes, which can then influence shape and morphology.