FACTBOX-Road leads from cloning to regenerated cells

(Reuters) - Researchers have used a handful of genes and a virus to transform ordinary pancreas cells in living mice into useful insulin-making cells.

The experiment builds on more than a decade of work with cloning techniques and the earliest embryos to learn how an egg and a sperm give rise to all the tissues, organs and blood in the body. Following are some facts about the research.

-- July 1996 - Dolly the sheep is the first animal to be cloned, using a technique called somatic cell nuclear transfer to reprogram a sheep's egg and make it behave as if it had been fertilized by a sperm.

-- November 1998 - James Thomson of the University of Wisconsin derives embryonic stem cells from a frozen human embryo.

-- As excited scientists begin working with these cells in the hope of founding a new field of regenerative medicine, politicians, ethicists and religious leaders around the world debate whether it is legal or moral to experiment on human embryos.

-- August 2001 - U.S. President George W. Bush unfreezes a 1994 law that forbids federal funding of research on human embryos. But he limits funding to a few batches of human embryonic stem cells already in existence.

-- Congress repeatedly votes to change the law starting in 2005 but Bush vetoes legislation in 2006 -- his first-ever veto -- and 2007.

-- November 2007 - Dr. Shinya Yamanaka of Kyoto University in Japan and Junying Yu of Thomson's lab transform ordinary skin cells into embryonic-like cells that they call induced pluripotent stem cells, building on work done by Yamanaka the year before in mice.

-- August 2008 - Dr. Douglas Melton of Harvard Medical School and the Howard Hughes Medical Institute transforms ordinary pancreatic cells into insulin-producing cells in living mice, using gene therapy techniques.

(Compiled by Maggie Fox in Washington, editing by Sandra Maler)