|Barbara McClintock. Public domain image. SOURCE.|
Transposons were first noticed in maize, which is sometimes mottled with different colors. The observed colors did not follow Mendelian genetics (Gregor Mendel was a friar, commonly called the Father of Genetics) which predicted colors based on the arrangement of chromosomes during meiosis (cell division). A new theory was required and it was developed by Barbara McClintock, who was consequently awarded the Nobel Prize in Medicine in 1983 for her work.
It was discovered that transposons are present in close to all living organisms and constitute 50% of human genes and 90% of maize genes. There are two major types of transposons: retrotransposons (which require RNA to be transcripted into DNA, using reverse transcriptase; they are the most common, making up over 98% of all transposons in the human genome) and DNA transposons (which do not require action from RNA). DNA transposons code for the protein transposase, which they use to remove and insert themselves along the genome. Autonomous transposons are capable of moving individually, but nonautonomous transposons need other transposons, since they don't code for transposase or reverse transcriptase on their own.
Transposons sometimes generate gene mutations. This can cause diseases, but can also be a way for an animal to respond to their environment, through adaptations.
There isn't a featured scientist this time. Instead:
Video of David Micklos and Susan Wessler of the Cold Spring Harbor Laboratory (where Barbara McClintock made her discoveries) explaining jumping genes:
Do you think the fact so many human genes can "jump" is a good thing or a bad thing?
-----The Golden Eagle