1962: Gurdon cloned frogs,
or did he?
John Gurdon of Oxford University announced in 1962 that he cloned South
African frogs with fully differentiated adult intestinal cells.
His experiment proved that cells retain the ability to form different
tissues even after they specialize. However,
certain flaws were found in his work.
Dennis Smith pointed out that there were some undifferentiated sex cells
in the intestines of South African frogs, so the tadpoles Gurdon cloned may very
well be cloned from those undifferentiated cells.
Marie A. Di Berardino also criticized Gurdonˇ¦s experiment.
She could not clone tadpoles using the nucleus of sperm cells.
Since sperm cells contained genetic information necessary to direct
an organismˇ¦s development, she speculated that nuclear transfer damaged the
nucleus and was a poor way to find out if a specialized cellˇ¦s genetic
information can develop an entire organism.
History of Cloning: Timeline