50. In this passage, the writer mainly .
A.
describes two types of people
B.
laughs at the unhappy people
C.
suggests ways to help the unhappy
D.
tells people how to be happy in life
C
An
Australian-based scientist announced yesterday he had made a step forward in forensic (用于法庭的) DNA
testing so that an individual can be identified by a single cell.
Ian
Findlay, from the Australian Genome Research Facility at the University of Queensland,
said current DNA testing required 200 to 500 cells to gain a similar level of
accuracy. "What we have done has brought that down to one cell," Dr
Findlay said after releasing details of his DNA testing technique at a Sydney conference.
The
technology could allow investigators to pick up DNA identities from plastic
cards and even build up a complete history of the people who have handled a
paper document.
"You'd
have to wear a space suit to stop yourself from leaving traces. You can
identify cells on the paper, so you can work out where it's come from and who's
touched it,” he said.
The
technique could also be used to trace the thrower of a punch(打孔)from
cells left behind on the skin of their victim. Even the wearing of latex(橡胶)gloves
would not help: small cells can pass through the gloves, and the constant flow
of genetic material given off by the human body would leave further evidence.
"We
gained a skin cell from a document dating back 30 years and managed to gain a
DNA fingerprint. DNA evidence can remain fresh for decades, perhaps even
centuries," Dr Findlay said.
"The potential for this technology to solve unsolved crimes is
great, "he said.
But Dr
Findlay, named scientist of the year in 1998 by the European Society of Human
Genetics, said the new testing needed to be scientifically validated, which would take up to
five years.
He said,
"There are serious consequences taking on technologies too early. The
public has to be sure that they have the utmost confidence in the security and
court systems."