b'31Team members on the jumping gene research (from left to right): Leon Lin, Lu Wang, Victoria Bonefont, Kun Dou, Sungjin Moon, and Zhao Zhang. Image courtesy Zhao ZhangSurprisingly, jumping genes barely moved in stemEgg developmentcells that produce developing egg cells, possibly(Stem cell gives rise to both Jumping gene-derivedbecause the stem cells would only have two copiesNurse cells and Oocyte ) virus-like particleof the genome for these jumping genes to use. Instead, the moving genes used the nurse cells, which could provide thousands of copies of the genome per cell. The nurse cells were used like factories to manufacture the virus-like particlesReproductivecapable of integration. Rather than integrating intoStem Cell Nurse cell Oocyte(Up to 2014nurse cells, they waited to be transported into ancopies of genome)interconnected egg cell, then added hundreds or more copies of themselves into the egg DNA. These parasitic genetic elements timed their activity andJumping genes, which mobilize around the genome, use nurse distinguished between different cell types to drivecells to manufacture invading products that preferentially integrate into the genome of developing egg cells called oocytes.evolutionary change and cause disease. Image courtesy Zhao Zhang'