:. °
“.° Ve= BIOLOGY AND MEDICINE’
‘Btolowy~6ot
the accumulation of “many “metant characters. At the Universi
sota the effects of radioactive substances on plat pathogens
Taine the biological significance and usefulness of changes ind
.radioactive materials.
_One of the initialphases of this stimy was to make. a EBEneral sur-_
vey of representative species of fungi to determine the effectIiveness of |
uranium.
The organisms were selected on the basis of genetic btability
or instability, nuclear conditions, and suitability from ¢ithef scientific
‘or economic viewpoints, and were grown on solid culture media fFontaining
uranyl nitrate. -Approximately 15 species of those tested prod heed sector
variants with this technique.
Mammalian genetics.
Important resuits in the mammalian
program at the ORNL includes confirmation of the rather tigh fk*«
partial sterility, believed to be dve to induced chromosomal - hariges in
“wWice after radiation. While data are still not extensive eno
broad conclusions, it appears that the frequency ofpartial st
“rather higher than might be expected for a given dosage based [bn chromone greater
some interchange frequency in plants and drosophila. Perhaps
number of chromosomes per cell may be partially responsible {a for Droso-
‘phila, 4O for mice, 48 for man).
Studies of the embryological effects of radiation of deweloping
|
embryos are being continued. Recent evidence indicates that dpses of 2550r, which are in the human fluoroscopy range, may have effects upon
“embryological development of certain characteristics.
Results of a pilot experiment to determine feasibility [of the proposed large-scale study of radiation-induced mutation of specific genes
became available during the past quarter. Results, which are encouraging
from the viewpoint of success of the experiment but: disturbing from the
viewpoint of the genetic consequences in mammalian species of tilization
of atomic energy on a large scale, indicate that the sensitivity of genes
in mice at. least is as nigh as in Drosophila and possibly: 50 qo 100. times
higher.
art CHIVES