© 1994 Nature Publishing Group http://www.nature.com/naturegenetics
© 1994 Nature Publishing Group http://www.nature.com/naturegenetics
© 1994 Nature Publishing Group http://www.nature.com/naturegenetics
© 1994 Nature Publishing Group http://www.nature.com/naturegenetics
© 1994 Nature Publishing Group http://www.nature.com/naturegenetics
© 1994 Nature Publishing Group http://www.nature.com/naturegenetics