Check Wikipdia. Best place to start is the American Constitution which if you're an American you should know backwards and forwards anyway. The Constitution is pretty clear, but lots of court rulings and infomal proceedures have generally expanded, in some cases restricted, his powers. Anyway too much to explain here.
There are two major types of DNA- Genomic DNA and Mitochondrial DNA; Genomic DNA / Nuclear DNA- This comprises the genome of an organism. This genomic DNA is spread across 46 chromosomes leading to an expression of genetic traits.The genomic DNA controls expression of the various traits in an organism.
1 Genetic testing is available from over 500 laboratories. 2  There are a number of different types of genetic tests available today, including:  Diagnostic testing - identifies a genetic condition or disease that is making or in the future will make a person ill.