Measuring amount of DNA

helperMom · Post by **helperMom** » Fri Jan 20, 2006 11:42 am

My son's science project involves extracting DNA from four different sources and then weighing or measuring the DNA somehow to see which sample produced the most genetic material. Does anybody have an easy way for him to do that? Thanks for any help you can give him.

MaryB · Post by **MaryB** » Fri Jan 20, 2006 11:48 am

Hi there,

Does your son have access to a lab that has a spectrophotometer? He could quantitate the DNA this way for each sample and compare yields. If this is a possibility, let us know and we can give you more details on how to do this, it is a fairly simple procedure.

Mary

helperMom · Post by **helperMom** » Fri Jan 20, 2006 11:50 am

Unfortunately he doesn't have access to a spectrophotometer. Is there something else he can use?

MaryB · Post by **MaryB** » Fri Jan 20, 2006 12:07 pm

Hi again,

Does he have access to agarose gel running equipment? Concentrations can be determined this way also.

There is also a DipStick kit made by Invitrogen for DNA quantitation - see link. This is an expensive kit (~$200).

https://catalog.invitrogen.com/index.cf ... antitation

I hope this helps.

Mary

helperMom · Post by **helperMom** » Fri Jan 20, 2006 12:10 pm

In other words, even though we can easily extract the DNA at home, we don't have any easy way of determining which sample has the most DNA?

MaryB · Post by **MaryB** » Fri Jan 20, 2006 12:20 pm

I am trying to think of an easy way - it would depend on the how much DNA you will be ending up with. If it is quantities that you can easily weigh then maybe you could weigh the material that you are starting with (i.e. whatever you are extracting the DNA from) and then weigh the resulting DNA from your extraction and determine %yield for each sample. What are you extracting DNA from? and how?

helperMom · Post by **helperMom** » Fri Jan 20, 2006 12:33 pm

I'm not sure exactly which method he chose to use but there are several sources on the Internet that involve a blender, ethanol, detergent and salt, and heating and cooling. He was going to use cow's liver and strawberries as his sources. We were thinking of using 8 ounces of each.

MaryB · Post by **MaryB** » Fri Jan 20, 2006 2:54 pm

Hi again,

I did a google search to try and determine the yield of DNA from tissue samples - see page 3 of the link below:

http://www1.qiagen.com/literature/broch ... i_p5_7.pdf

From 25 mg of animal liver the yield is approx 10-30 ug (micro-grams) of DNA using the kit described in the link - so from 8 oz (=226000 mg) of animal liver you would expect about 90400-271200 ug or 90-270 mg of DNA (if my math is correct). So if you have an accurate way to measure mg quantities and your DNA isolation procedure works as well or better than the kit described then this may work for you.

I hope this helps.

Mary

helperMom · Post by **helperMom** » Fri Jan 20, 2006 3:01 pm

Thank you. You've been very helpful.