Title page for ETD etd-03132009-040450
|Type of Document
||Keil, Clifford B.
||Chromosome banding of German cockroach spermatocytes
|Ross, Mary H.
|Cochran, David G.
|Mullins, David E.
|West, David A.
|Date of Defense
A chromosome banding protocol for Blattella germanica
speramtocytes was developed to reveal locations of constitutive heterochromatin (C-bands). Normality of the
acid treatment used to denature basic (histone) proteins,
temperature of the salt solution used to extract DNA from
unhanded regions, and the components of the Romanowsky-type stain proved to be critical components in the C-banding process. The thiazine component of a standard Gieasa stain
had an absorbance maximum altered from that of methylene
blue, the putative major thiazine in this stain and was
ineffective in producing C-bands. Two samples of Leishman's
stain were examined chromatographically,
spectrophotometrically, and for their C-bandinq ability as
they aged. Banding failure was accompanied by a rounding of
the thiazine spectral peak and the appearance of unknowns
with cbromatographic mobility intermediate to azures A and
B, and an apparent increase in azure C content.
Experimental thermal and photo-degradation of Leishman's
stain shoved similar alterations of the thiazine components.
c-banded prop base II and diplotene kacyotypes revealed a
hiqhly heteroaorphic pattern of C-band distribution. Blocks
of constitutive heterochromatin were not soley associated
with centroaeres bat occurred interstitially and terminally
also. One chromosome was C-band negative, number 8, while
two others. 9 and the X, were almost completely
heterochromatic. Differential rates of condensation from
prophase I to prophase II for euchromatic and
heterochromatic regions were documented. The karyotype of B. germanica contained many gray bands that may indicate euchroaatin interspersed with heterochromatin.
Translocation heterozygote stocks were used to correlate the
banded karyotype with linkage groups. Translocation
multivalents frequently contained C-bands Dot resolved in
wild type chromosomes. A C-banded prophase II karyotype of
a closely related species, Blattella vaga, was prepared to
assess the variability of heterochromatin distribution. The
basic banding pattern was preserved in four of the twelve
chromosomes although the bands were larger in this species.
Tvo chromosomes, 11 and 8, had a single additional C-band in
each. The basic banding pattern was preserved in four of the twelve chromosomes although the bands larger in this species. Two chromosomes, 11 and 89, had a single additional C-band in each. The B. vaga X chromosome was about twice as large as
that in B. germanica. The mid-sized chromosomes were
Overall, B. vaga chromosomes were longer than those of
B. germanica. Increased
heterochromatin content appeared to be the cause of the
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