Evening star., 1949-09-14
100, 900 Mice to Be Used
In Radiation Experiments
Oak Ridge Scientists to Study
Ray Effects on Heredity
By Thomas r. Henry

OAK RIDGE Tenn. Sept 14.-More than
100000 mice will be used In 1O-year
experiment started at the Atomic Energy
Commissions laboratories here to determine
the effects of radiation on heredity OF warm
blooded animals.
The geneticists expect to obtain as much
information as could be gotten in 5000 years
from the study Of human beings who, follow
about the same hereditary laws as mice.
The little animals produce five or six gen.
erations a year. The average length OF
human generation is Is years.
At present, according to DR.. A. H Hol-
land jr., director of biological research at
Oak Ridge, very little is known Of human
or mammal genetics and much that Is
supposed to be known may be all wrong.
Very little actually is being learned from
study of the survivors Of the Japanese bomb
ings who were subjected to very heavy
radiation which theoretically might be ex-
pected to produce many abnormalities in
their descendants. Every birth in this group
is being watched carefully, but the japanese
birth rate normally is high and there is
tendency to destroy malformed children.
Thus bad effects of the bombings never
might become known.
ALI Types OF Radiation.
The mice will be subjected to all known
types OF radiation Of various intenSities.
Then they will be crossbred in different ways
and the effects Of each mating carefully
noted.
A great deal Of present information about
heredity, DR.. Holland points out, has been
obtained from studies of fruit flies which
have the advantage Of producing many gen.
erations each year. Thus the effects OF
any change in environment will be renected
almost at once in the new generations.
This has been an excellent procedure for
,loN FOL Of stressed
but there is increasing evidence that men do
not follow the same rules as fruit hies
They do, by and large, act genetically about
the same as mice.
The mice are of several strains which
carefully have been bred for many genera
tions. There are no unknown factors IN
their heredity so that any demonstrably
genetic changes logically can be attributed
to the radiation to which they are subject.
At the outset Of the experiment the Oak
Ridge biologists tend to somewhat optimis-
tic view of the danger that radiation seri-
ously damages the heredity of warm blooded
animals There doubtless will be some mon
sters" among the progeny and there may be
some beneficial changes.
Competitive Affair.
But, as DR.. Holland explains. mammal
conception Is competitive affair. First
there is what amounts to a race among the
sperm to reach the ovum and any that nave
been weakened or otherwise damaged by
radiation are almost certain to lose out.
Second, the ovum also usually dies when
damaged sufficiently for heredity to be af-
fected. Obstetrcians now believe that this
is the reason for most spontaneous abortlons.
Nature is highly conservative and has pro-
vided these safety factors against too rapid
change in the pattern of race.
The majority OF the genetlc changes
brought about by radiation, the Oak Ridge
experimenters believe, will be what are known
as "recessives" They will have no effect on
offspring unless the same changes are COM
mon to both parents, which is quite unlikely.
There is common opinion that all the
changes which may get foothold in the
race will be damaging. This is by no means
justified by past experience, the experiment.
ers claim, and it Is quite within the cards
that very superior breed OF mice will be
produced.
No definite conclusions will be formed.
1t is stressed, until the ten year period Of the
experiment Is over.