.
c
409994
[he beetle acquires a golden ap.!rtce (which is absent in strains
~re not au) that is evident even
c presence of body-color genes such
e[y (3).
I order to assess the effect of the
:cne. counts of setae were carried
.~n two parts of the body of ten
M derived from the au and ten
I the normal Texas stock, namely,
;entral portion of each visible abnal sternite and the distal portion
.Imputated
memand mounted
.ous wings which is free of veins.
‘w sternites, the setae were counted
a single area 0.01 mm: in the
NC of the sternite, with the aid of
(ic?e in a 1SX ocular in comhina\\,i[h a 10X objective. In the mem!Y.IS
wings the setae within five
. of each wing selected at random,
i 0.02 mm~. were recorded with a
ocular and 44x objective.
: the sternites of the normal beetles
:]Sean setal number in a sample of
>pecimens varied from 9.4 ti 0.2
‘~.7 & t).4 setae. In au these values
wd from 23.7 = 2.1 to 30.6 & 1.4
.’. or approximately
two to three
. as many as in the normal beetles.
.he membrwtous
wings the mean
:ber of setae in the sample of 50
\urements in each strain was I 0.84
~~ for the normal and 11.10 & 1.66
{he mutant. The difference in the
I means is not statistically significant
. .4).
‘he micrographs
obtained with the
nning electron microscope are shown
eig. 1. At the top, on the lefi is
w part of the head and the pro~tx of the normal beetle, and on
right that of the au mtitant. Clearly,
number of pits and associated brisicre greatly increased in these two
m of the body. The cervical
bristles
!he anterior” margin of the prorux are also greatly increased in
nber.
1he micrographs
of the abdominal
mites (in the middle of Fig. 1) show
what extent the number of pits and
.tles is increased in the mutant. ~lnal.
on the bottom of the figure are two
~rographs which contrast the commd eye of the normal and the mu! In the normal beetle (left) there
ordy single bristles between the omlidia, while in the mutant (right)
interornmatidial
bristles are often
:ibled.
rhe cytogenetic basis of most mu[s other than those from Drosophila
ii~
I[!LY 1967
Refesenee*
tnelanogaster
is not known. In Drosophila the sex-linked dominant Hairy-
1. T. L. Hayes,
wing (Hw) increases the number of
hairs present in the normal wing. For
exarnpl% in Hw/ + females the number is increased by about 17 hairs, in
Hw/Hw
by about 21 and, combined
with a duplication (Dp), in Hw/ Hwl Dp
by about 33 extra hairs. The increase
in hair number was less marked in
males.
Cytological examination and genetic
data revealed that the increase
in
hair number resulted from a duplication. The duplication essentially doubled
the number of extra hairs on the wing
(4). The autosomal recessive “hairy,”
which increases the numbers of hairs
on the wings and other parts of the
body, interacted with Hw to increase
the number of hairs on the wings even
further (5).
In Triboliurn the cytogenetic basis
of the aureate mutation has not been
investigated because, even with the most
powerful compound
microscope,
the
chromosomes are too small to detect
chromosoma[ aberrations such as duplications or deletions. As techniques are
developed in conjunction with the scanning electron microscope, it should be
possible to examine cytological material
and determine whether chromosomal
aberrations
(such as duplications
in
Drosophila)
are responsible
for the
modMcation of the phenotype of Triboliurn.
Be that as it may, our data indicate
that the aureate mutation in its effect
appears to be unique so far, not only
but for the
for the genus Tribolium
order Coleoptera (6). Furthermore,
because the scanning electron microscope
gives micrographs
of high resolving
power even at high magnifications,
it
has been possible to obtain a detailed
record of the phenotype of normal and
mutant to a degree not previously attainable.
A. SOKOLOFF
Department
of Genetics,
University
California, Berkeley, and Natural
Sciences Division, California State
College, San Bernardino
of
T. L. HAYES
Law’rence Radiation Laboratory,
University of California, Berkeley
R. F. W. PEASE
Electronics Research Laboratory,
University of California, Berkeley
M. ACKERMANN
Department of Genetics,
Univer.rity of California, Berkeley
Donald, Lab.
and
Notes
R. F. W. Pease,
L. W. Mc-