Scientists have brought us a step closer to stopping genetic diseases before they pass from one generation to the next. Researchers have figured out how to introduce corrected genes into sperm so that future generations inherit only healthy genes. The scientists conducted the experiment on mice but if the process works on humans, it could mean the end of many genetic disorders.

Genes work like an instruction book for the body. The human body has about 20,000 genes. Variations in these genes make each person unique, determining factors such as eye color and height.

People inherit their genes from their parents. Defects in the genes continue for many generations to cause a family history of illness. Currently, scientists are investigating ways to replace defective genes with healthy ones to interrupt the passage of genetic disorders from one generation to the next.

Researchers from The Royal Veterinary College in North Mimms, United Kingdom, inserted a brightly colored marker into the sperm of mice. This marker, known as green fluorescent protein or GFP, gives Aequorea Victoria jellyfish their ability to glow in the dark. Scientists use GFP in research because its luminescence makes the marker easy to see once it is inside an organism.

After inserting this marker into mouse sperm, Anil Chandrashekran, Ph.D., and her team of researchers looked for - and found - glowing bits of GFP in the tissue of the next generation. The scientists noted that as many as 42 percent of the mice with GFP-laced sperm passed the marker onto their offspring. What was even more remarkable was that the offspring actually passed on the GFP genetic marker onto the next generation of mice.

This discovery could someday help medical professionals end some types of genetic disorders, such as breast cancer, skin and colon cancer, Down syndrome, Parkinson’s disease, and sickle cell diseases. Scientists could simply replace defective genes with healthy ones in the father’s sperm. This protection from genetic disorders is transgenic, meaning it lasts from generation to generation.

Source: Chandrashekran, Anil “Efficient generation of transgenic mice by lentivirus-mediated modification of spermatozoa.” The Journal of the Federation of the American Societies for Experimental Biology 12. (2013). The FASEB Journal. Web. 10 Dec. 2013