We counted the number of times we saw a copy of a gene in normal tissue and then in the diseased one, says David Searls, SmithKlines director of bioinformatics.

FORBES: A hail of silver bullets

Minute quantities of abnormal a-syn from older diseased mice exhibiting neurological symptoms were injected into one mouse group.

WSJ: Exercise Benefits vs. Joint Concerns

"This chemical acts as the eyes and ears of the immune system, scouring the body for diseased cells, " said Heather Andrews, one of the researchers.

BBC: Breast cancer trigger investigated

The family left the hospital briefly in mid-January and then returned to Johns Hopkins for the bone marrow transplant that would replace Zoe's diseased immune system with Maxine's healthy one.

FORBES: Two Girls Two Countries One Cancer

For children born with a windpipe defect or without one, and for others with defective or diseased organs, manipulating stem cells to generate healthy tissues or organs could be their only chance at survival.

CNN: Toddler gets new windpipe from her own stem cells

Doctors hope to use this research one day to give people new cells to replace diseased or damaged ones.

CNN: NIH publishes draft guidelines for stem cell research