Science Buddies: "Ask an Expert"

I have a question about salivary amylase. I'm doing an experiment measuring how fast it digests starch. That's easy enough, but I want to know how this information can be useful. I know that the salivary amylase protein expression positively correlates with the AMY1 gene copy number variation. I want to see if I could use the time it takes for a certain amount of saliva to digest starch to approximate how many copies of this gene you have. Is this possible and if it is, how can I test this?

Measuring the time it takes for salivary amylase to convert polysaccharides into disaccharides would be the easy part of the experiment. Determining how many copies of the AMY1 gene an individual has is difficult because it would require either DNA sequencing or thermocycling using primers specific for the AMY1 region.

You could test the saliva for the amount of amylase it contains, but that would require running salivary proteins on an acrylamide gel to separate them, transferring them to a blotting membrane and identifying the amylase band using an antibody raised against the amylase protein.

This is a common procedure in molecular biology labs that I have done hundreds of times, but it requires much more equipment, reagents and training than a high school lab has. If you have access to a university biomedical research lab, you could do this procedure. They would also have a thermocycler that should allow you to determine how many copies of the AMY1 gene are present in an individual's DNA.

You can run many saliva samples and determine the variation in time for conversion of a certain amount of starch to sugar but finding out the gene copy number will be impossible without access to a university lab.

Let me know if you have more questions.

Sybee