Page 164 - The Evolution Impasse 2

162 Pithecanthropus erec tus

di tion to the main DNA strands, or
chro mo somes. A plas mid is a small
DNA ring found out side the chro -
mo somes in many spe cies of bac te -
ria. A round ed DNA mol e cule of no
fun da men tal im por tance to the bac -
te ri um, a plas mid—ac cord ing to ev -
o lu tion ists—pro vides se lect ive ben -
e fits. This plas mid DNA's round
shape en a bles it to en ter or leave the
bac te ri um with ease. This fea ture of
plas mids led to DNA com bi na tion
A de pic tion of Piltdown Man, based on re search.
the fraud u lent fos sil
Plasmid trans fer is one of the
tech niques that sci en tists dis cov ered
"the ev i den ces of ar ti fi cial ab ra sion
for the pur pose of com bin ing DNA.
im me di ate ly sprang to the eye.
Research in to new ly com bined (re -
Indeed so ob vi ous did they seem it
com bi nant) DNA is per formed by
may well be asked—- how was it
com bin ing the DNAs of dif fer ent or -
that they had es caped no tice be -
gan isms to ob tain large enough
fore?" 184
quan ti ties of spe cif ic genes to be able
Piltdown Man, which had been
to study them. Many bi ol o gists re -
ex hib it ed for the pre vi ous 40 years
gard this meth od as one of the most
or so, was then hur ried ly re moved
val u a ble means of bi o log i cal re -
from the British Museum.
search yet dis cov ered. 185
One of the dis cov er ies re vealed
by this tech nique is bac te ria's an ti bi -
PITHECANTHROPUS EREC -
ot ic re sist ance. The genes of bac te ria
TUS
that have proved re sist ant in the past
—see Nebraska Man Fraud, The.
are trans mit ted to oth er bac te ria by
way of plas mids. Resistant genes are
gen er al ly found in plas mids. In this
PLASMID TRANSFER
way, a re sist ant gene ac quired by a
Bacteria con tain a small DNA non-re sist ant bac te ri um can eas i ly
mol e cule known as a plas mid in ad - be add ed on to its own DNA. This

The Evolution Impasse II