Washington, (Agencies): American Scientists have found  "jumping genes" in humans, which contain several pesky mobile elements that may help to explain why people have
such a variety of physical traits and disease risks.

A Johns Hopkins University team has revealed 1.016 new insertions of RIPs or retrotransposon insertion polymorphisms, thereby expanding the catalog of insertions that are present in some individuals and absent in others.

The standard assembly of genetic elements as outlined in the reference human genome to raw whole-genome data from 310 individuals made available by the 1000 Genomes Project.
Retrotransposons are travelling bits of DNA that replicate by copying and pasting themselves at new locations in the genome. Having duplicated themselves and accumulated over evolutionary history, transposable elements now make up about half of the human genome.
"In any individual, only between 80 to 100 retrotransposons are actively copying and inserting into new sites," said lead scientist Haig Kazazian.

"We're not only discovering where they are and who has which ones, but also finding out that they insert with a remarkable frequency -- on the order of one in every 50 individuals has a brand-new insertion that wasn't in their parents," he added.