a
Table 1 are presented graphically in Figure 1 to show the relationship
between the age at exposure and the isoleucine substitution frequency.
For some of the samples, sufficient globin remained to separate the
& and & chains and to determine the isoleucine substitution frequency in
the separated chains (Table 2).
A tracing of the chain separation of
sample 24R is shown in Figure 2.
The small peaks just ahead of the major
8 and a chain peaks are commonly observed (see Discussion) and for a few
samples these small peaks were analyzed separately (Table 2).
The average isoleucine substitution frequency as a function of
radiation exposure is plotted in Figure 3.
Discussion
A slight, but invignificant, increase in the isoleucine substitution
frequency was found is contrals between ages 20 and 51; the regression
line has a slope of 0.9234 ¥ 107°.
More data on older and younger persons
should be collected to determine whether the isoleucine substitution frequency
increases linearly with age; it has been suggested that the error rate in
protein synthesis shouid increase exponentially as a function of age’.
In
this regard, the high value obtained for sample 1547 is interesting because
she is a 60-year-old woman showing signs of senility.
Except in sample 1547,
the higher isoleucine substitution frequencies were in samples from exposed
individuals; however, some exposed persons had values in the control range
(Table 1).
T tests show that the 175 R and 69 R groups are not significantly
different, p>. 25; at the 95% confidence limits the former is significantly
different from controls, p<.03, but the latter is not, p>.08.
Figure 1 shows
weve
CI
as
co
Cry
that the higher isoleucine substitution frequencies were observed: more often