DNA testing

[chillygirl92]

I need a DNA testing kit that I can use to test the changes in the DNA of bacteria from separate generations. Do you know of any good ones I can use and explain to me how it works? I understand that it works with electrolysis, and I understand that it separates it by how large the molecules are, but I don't understand how the genes are separated. Thanks!

[deleted-71417]

Hi,

You have asked a very good question that would take a post graduate molecular biology course to adequately answer. I can give you a few approaches that you will have to develop on your own.

You asked how the separation methods work. Most approaches use electrophoresis on agarose or polyacrylamide gels to separate fragments of dna, often after amplifying the amount of dna using a PCR (polymerase chain reaction) method. Here are discussions about using electrophoresis on agarose gels:

http://en.wikipedia.org/wiki/Gel_electrophoresis

http://www.methodbook.net/dna/agarogel.html


Here are some papers describing approaches to dna fingerprinting:

http://www.natureprotocols.com/2007/05/ ... finger.php

http://www.accessexcellence.org/AE/AEC/ ... rs_dna.php

http://www.hindawi.com/getarticle.aspx? ... 4302206026

http://www.encyclopedia.com/doc/1E1-DNA-fing.html

One classical approach to monitoring SNPs/gene mutations in DNA uses the Southern Blot:

http://answers.yahoo.com/question/index ... 047AAFlBZK

http://www.bio.davidson.edu/COURSES/gen ... nblot.html

http://en.wikipedia.org/wiki/Southern_blot

http://www.piercenet.com/Proteomics/bro ... B9802A393D


Another approach is DNA micro arrays:

http://en.wikipedia.org/wiki/DNA_microarray


You asked for recommendations for DNA test kits. I cannot give any. If you have worked your way through this answer this far, several things should be obvious to you. 1) It would really help to have a skilled mentor to help you learn the lab techniques involved; 2) you will need access to chemicals and equipment that will be difficult and costly to get on your own, and will pose safety of handling and problems of safe disposal. I suggest you investigate whether you can get access to what will be needed through your high school or local college or university. A skilled local professor of molecular biology would be a godsend of a friend in a project like this.

This sounds like a fascinating project to attempt, and could provide invaluable experience and a good headstart toward a career in molecular biology. I wish you every possible success with it.

Best regards,

Barrett Tomlinson

[deleted-71710]

Hi chillygirl92, this is indeed a very challenging project for all the reasons listed above! Often times it's regulation of gene expression and the products of genes (RNAs and proteins) that provide more valuable information, not just the DNA sequence itself. Can you tell us more specifically what aspect of the genome you are interested in monitoring and the proposed experimental question? Knowing what information you're looking for would help determine what tools would be required to collect data.

If you want to study particular gene it's possible to choose one that does not require highly specialized equipment. For instance, you could pick one (or a group) that's responsible for a morphological feature that can be observed under a microscope. You could also choose a specific protein that is relatively easy to measure and see how it's expression changes over time when when subjected to different environmental conditions (this would be the more challenging of the two suggestions).

Good luck!
Ryan