A human-sheep chimera has been created by scientists at the University of Nevada-- 15% of the animal's cells are human. The goal of their experiments is to develop animal organs that can be successfully transplanted into humans. Read more at The Mail(1) and the Reno Gazette-Journal(2).

1. http://www.mailonsunday.co.uk/pages/live/articles/news/news.html?in_article_id=444436&in_page_id=1770&in_a_source=
2. http://www.rgj.com/news/stories/html/2005/03/30/95831.php