What is a "jumping gene"

What could happen if transposons "jump" into an organisms genes.
Could this affect an organism's fitness?

I'm trying to study for a Biology test but I can't even find this term in my book. If you happen to have the 'Indiana, Miller and Levine Biology book a chapter or page number would be super helpful! Please help!

Every few cell division, transposons will copy it self and simply pick up and move else where, jumping at random to a new location on the chromosomes taking the genes with it. To be frank, transposons effect genes when they move, or jump to a different location and cause mutations. If it doesn't cause a mutation, it inactivates the gene. For instance, in Indian Corn, some pigment genes are not expressed in some cells because they have been disrupted by jumping genes.

hopes this helps :)

They are defined as small, mobile DNA sequences that first replicate and then insert new copies at random sites.
http://www.biology-online.org/dictionary…

Transposons exist in recognized families based on length, method of insertion and method of replication if they have an RNA reverse transcription step.

Types of Transposons:
http://users.rcn.com/jkimball.ma.ultrane…
http://www.nature.com/scitable/topicpage…
http://transposons.tripod.com/id5.html

Look for SINEs like the Alu sequences in humans.
http://en.wikipedia.org/wiki/Retrotransp…

If a transposable element is inserted into a gene, it will most likely reduce or prevent transcription of that gene. If for example, the white gene in Drosophila is disrupted, the fly will develop white eyes and will be blind. This obviously has an effect on its fitness.