Researcher shows eggs are eggs

A Harvard Medical School researcher's claim that women might someday be able to generate new eggs appears to have been exploded.

The work was done by another Boston scientist, the Boston Globe reported.

Jonathan Tilly's report that mice appear to have germ cells that can generate new eggs raised hopes that women's reproductive years could be extended with injections of stem cells. He had apparently disproved the theory that women are born with all the eggs they will ever have.

Amy Wagers, a scientist at the Joslin Diabetes Center, used a tool known as "parabiotic mice" to demonstrate that Tilly's work had problems. Those are mice genetically engineered so one has cells that glow green, and joined with another mouse without the engineering so the two share one circulatory system.

If Tilly's theory was right, each mouse would eventually have some eggs that had originally been germ cells in the other mouse and had been circulating in its blood. But that never happened, the Globe reported.

Copyright 2006 by United Press International

Related stories:

Location, location, location important for genes, too
Cells become cancerous mainly because they lose control of their growth. To better understand how this happens, a new study at Ohio State University's Comprehensive Cancer Center looks at four genes that help regulate cell growth in embryos and that contribute to cancer in adults.
Maelstrom quashes jumping genes
Scientists have known for decades that certain genes (called transposons) can jump around the genome in an individual cell. This activity can be dangerous, however, especially when it arises in cells that produce eggs and sperm. Such changes can threaten the offspring and the success of a species. To ensure the integrity of these cells, nature developed a mechanism to quash this genetic scrambling, but how it works has remained a mystery.
Scientists announce mouse sperm cryopreservation breakthrough
A team of Jackson Laboratory scientists have figured out a simple, cost-effective process to freeze mouse sperm and get it to achieve high fertilization rates with mouse eggs. The breakthrough will greatly reduce the cost of developing and distributing new mouse models of human disease.
Prevailing theory of aging challenged in Stanford worm study
Age may not be rust after all. Specific genetic instructions drive aging in worms, report researchers at the Stanford University School of Medicine. Their discovery contradicts the prevailing theory that aging is a buildup of tissue damage akin to rust, and implies science might eventually halt or even reverse the ravages of age.
Study points to cocktail therapy for Alzheimer's
A dietary cocktail that includes a type of omega-3 fatty acid can improve memory and learning in gerbils, according to the latest study from MIT researchers that points to a possible beverage-based treatment for Alzheimer's and other brain diseases.
Stem cell discovery sheds light on placenta development
Researchers studying embryonic stem cells have explored the first fork in the developmental road, getting a new look at what happens when fertilized eggs differentiate to build either an embryo or a placenta.
Caution on stem cell therapy
A single organ may contain more than one type of adult stem cell – a discovery that complicates prospects for using the versatile cells to replace damaged tissue as a treatment for disease, according to a new study from the laboratory of geneticist Mario Capecchi, the University of Utah's Nobel Laureate.
Disabling mouse enzyme increases fertility
Changing the sugars attached to a hormone produced in the pituitary gland increased fertility levels in mice nearly 50 percent, a research group at Washington University School of Medicine in St. Louis has found. The change appears to alter a reproductive "thermostat," unveiling part of an intricate regulatory system that may one day be used to enhance human fertility.

News discussion:

Medicine & Health news