Monday, November 24, 1997
Long before biotechnology discovered restriction enzymes, nature
devised a way for pieces of DNA to move directly from one spot in an organism's genome to
another, without any intermediate. These mobile elements, or transposons, were first
described by Barbara McClintock in the 1940s during her studies of corn genetics.
Transposons jump when an enzyme called transposase binds to specific sequences at the ends
of the transposon DNA, cuts out the DNA and inserts the transposon at a new site on the
same or different chromosome.
Transposons have been used in invertebrate, plant, and bacterial
systems to randomly insert genes or markers into the genome, or for the directed
incorporation of DNA into host organisms.