WASHINGTON, Jan 17, 2008 (AFP) - A California company announced Thursday that it has created cloned human embyos from adult skin cells, a breakthrough which could ultimately lead to the development of cures for Alzheimer's disease, Parkinson's, and other untreatable ailments.

Stemagen Corp., a private company based in La Jolla, California, used a technique called somatic cell nuclear transfer (SCNT) to create the embryos.

In their experiements, the researchers removed the nuclei of mature egg cells from healthy young women who had previously donated eggs for successful infertility treatments.

Scientists then inserted DNA from an adult male donor into the eggs. DNA used in the experiment was retrieved from cells called fibroblasts, which are obtained from skin biopsies.

Several of the reconstructed eggs continued to develop as normal embryos, and three of the embryos were shown in genetic tests to have the same DNA as their male fibroblast donors.

'This study demonstrates, for the first time, that SCNT can be utilized to generate cloned human blastocysts using differentiated adult donor nuclei remodeled and reprogrammed by human oocytes,' the researchers wrote in the study, which appear Thursday in the online edition of the journal 'Stem Cells.'

They believe that some key technical factors contributed to their successful results, including the use of freshly donated oocytes from successful egg donors.

Researchers said the breakthrough could lead to the creation of patient-specific embryonic stem cells for the development of treatment for as yet uncurable illnesses.