Using an ALU Insertion Polymorphism to Study Human Populations
Although DNA from any two people is more alike than different, many chromosome regions exhibit sequence differences between individuals. Such variable sequences are termed “polymorphic” (meaning many forms) and are used in the study of human evolution, as well as for disease and identity testing. Many polymorphisms are located in the estimated 98% of the human genome that does not encode protein.
This experiment examines a polymorphism in the human genome that is caused by the insertion of an Alu transposon, or transposable element. Alu is a member of the family of short interspersed elements (SINEs) and is approximately 300 nucleotides in length. Alu owes its name to a recognition site for the endonuclease AluI in its middle. Although Alu is sometimes called a “jumping gene,” it is not properly a gene, because it does not produce a protein product.