
                         Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: THURSDAY, April 12, 1990                   TAG: 9004120478
SECTION: NATIONAL/INTERNATIONAL                    PAGE: A13   EDITION: STATE 
SOURCE: Associated Press
DATELINE: NEW YORK                                LENGTH: Short

20-MILLION-YEAR-OLD LEAF REVEALS GENETIC DETAILS

Researchers say they have achieved a detailed analysis of genetic material from 20-million-year-old magnolia leaves, by far the oldest plant or animal tissue ever to yield such information.

Co-author Michael Clegg of the University of California, Riverside, reports the work in today's issue of the British journal Nature.

The leaf samples, from an excavation in the panhandle area of northern Idaho, were 17 million to 20 million years old. The oldest material that previously had yielded to similar genetic analysis was human brain tissue about 7,000 years old, recovered from a bog in Florida, Clegg said.

Genetic material, called deoxyribonucleic acid or DNA, was extracted from leaf samples and a portion of it was duplicated repeatedly using a technique called polymerase chain reaction.

"The fact that we could do it once probably means it can be done again" with materials from other sites, Clegg said.

But he acknowledged that the leaf samples were exceptionally well preserved, having originally fallen into a cold lake that rapidly silted in. The cold and the low amounts of oxygen available helped preserve the leaves, he said.

by CNB