Title page for ETD etd-03132009-040445


Type of Document Master's Thesis
Author Keil, Clifford B
URN etd-03132009-040445
Title Basic studies of chiasma frequency in male Blattella germanica (L.)
Degree Master of Science
Department Entomology
Advisory Committee
Advisor Name Title
Ross, Mary H. Committee Chair
Cochran, David G. Committee Member
Grayson, James McD. Committee Member
West, David A. Committee Member
Keywords
  • Insects
Date of Defense 1979-05-05
Availability unrestricted
Abstract
This investigation represents the first thorough examination

of chiasma frequency in the primitive orthopteroid insect, Blattella

germanica (L.). The data obtained are useful both in advancing our

knowledge of cockroach genetics and in stimulating comparative cytogenetic

studies. A pilot study was conducted to ascertain appropriate

sample sizes and to assess the feasibility of more extensive investigations.

Experimental animals were reared in a constant temperature and

humidity chamber and segregated according to whether they emerged from

a first, second, or third ootheca. The testes of third to fourth

instar male nymphs were removed, stained with acetic orcein, and

examined for suitable numbers of cells at diplotene-diakinesis.

Analysis of the chiasma frequency data showed a decrease in mean

chiasmata per bivalent: 1.3325 ± 0.0184 for the first oothecal group,

1.2999 ± 0.0165 for the second oothecal group, and 1.2525 ± 0.0113 for

the third oothecal group. The variances decline with the means.

The chiasma frequency of a stock heterozygous for a reciprocal

translocation involving two mid-sized chromosomes, eight and nine,

was compared to the wild-type freq9encies. In comparison with the

first oothecal group, an elevated chiasma frequency, 1.4176 ± 0.0062

chiasma per bivalent, was found. The translocation had the effect of

raising chiasma frequency in the two bivalents involved. No interchromosomal

effect on chiasma frequency was observed, due to the

presence of the translocation. It was noted that in B. germanica,

chiasma frequency is probably not positively correlated with bivalent

length.

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