about 13 million mutation-bearing conceptions of the lethal variety.
A small but undetermined proportion of these will be expressed as
lethal dominants and will be eliminated in the first generation, many
as early miscarriages.
Approximately 4% of the recessive lethal genes
will also come to expression as genetic deaths in the firat generation
and these will amount to approximately 20,000 conceptions per year out
of the expected 2,700,000 births per year.
If we add to this the ex-
pected genetic deaths from the detrimental mutations, twice the number
of lethals with an assumed maximm of 4% for the detrimental factor,
there can be a total of 60,000 genetic deaths per year for the first
generation out of the expected 2,700,000 births per year.
This rate
will decrease with time until the total number of genetic deaths equals
approximately one-half to one-third of the 13 million lethal plus 26
mil1ion(detrimental)mutations.
It is worth pointing out that an informal exercise at RAND
which assumed 150 15 Mr
kreapons dropped over the
United States, east of the Mississippi, resulted in the delivery of
. approximately 86 r/person to the total population of that area, i.e. ,
east of the Mississippi, on the further assumption that shelter giving
90% protection was available and used by everyone.
This condition
would reduce the totals given in the example above by a factor of 2,
because of the fact that the immature germ cell mutation rate would
apply for the bulk of the radiation exposure.
The amount of additional
genetic damage caused by radiation after people leave their shelters
will depend on decontamination, weathering, gross terrain shielding, and
other factors.
It appears, therefore, that a large amount of radiation will
not present an inordinate genetic effect as long as the radiation is
applied to one generation only and is not repeated.
Repeating the
dose discussed above, generation after generation, would before
many
generations reach a new mutation rate which could be incompatible with
species survival.
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