RFLP “Restriction Fragment Length Polymorphism” Basic idea: Uses: If two DNA sequences have different numbers or locations of restriction sites, they will differ in their restriction enzyme digest pattern Uses: Paternity testing Criminal cases Locating disease genes

Criminal Case http://www.scientific.org/case-in-point/articles/thompson/

Paternity/Maternity testing Child 2 Child 1 Dad Mom

Recombinant DNA Engineered pieces of DNA inserted into the genomes of a target organisms Can be used to mass produce useful proteins “Humulin” – human insulin produced by bacteria (Eli Lilly company) Human growth hormone Also used to modify organisms All originally depends on restriction enzymes!

Gene cloning with restriction enzymes

GloFish

Why do bacteria not cut their own genomes? They protect their DNA with methylation http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.asp?JournalCode=OB&Year=2009&ManuscriptID=b813595a&Iss=1 Restriction enzymes can’t cut here

Optical Mapping Image of single molecule of DNA after being cut by restriction enzymes EagI & MluI Laboratory of David Schwartz, UW-Madison