) ‫أنموذج ( أ ) الخاص برسائل الماجستير و اطاريح الدكتوراة ( اخر شهادة‬
University of Baghdad
College Name
Faculty of Science
Department
Department of Zoology
Full Name as written
in Passport
Nazar Aziz Auda
e-mail
Career
Thesis Title
nizarly@yahoo.com
Assistant
Assistant
‫٭‬
Lecturer
Professor PhD
Professor
Lecturer Master
‫٭‬
“Genetical and Irradiation Studies in Relation to Meiotic Drive in the
Mosquito Aedes aegypti (L.)”
Year
1979
The studies reported in this thesis refer to four aspects of genetics in
Aedes aegypti:
Abstract
1.The genetic basis of resistance to meiotic drive by the Y(M) – linked gene D
A resistance factor t (tolerance to MD) linked with re (red eye) on
chromosome 1 was isolated from the RED strain. t exerted its greatest
effect when in coupling with ms . However, even the t/t homozygote did not
entirely counteract sensitivity associated with ms .
Genes on the autosomes affected the expression of t. The CHIPEI
background genotype totally suppressed it (although the effect was lost in
a few generations) while autosomal genes inherited from Red, linked with
markers on chromosomes II and III, mostly enhanced it, a particularly
strong effect coming from a factor associated with the marker bw (brown
eye).
These conclusions have been derived from studies of T-30 and ACCRA
strains. Meiotic drive in the MWAMSABU strain seemed to have a
different basis although also causing excess male production. In the case
of MUAMSABU, t enhanced the sensitivity of the X- chromosome to Mlinked meiotic drive rather than suppressing it.
2.Variation in eye colour
An eye colour gene bw , causing brown eyes when homozygous, and
probably located on linkage group II close to y, has been investigated.
It shows good viability and penetrance and it has been kept as a pure
stock.
bw interact with re, the double homozygote being colourless, with a
pentrance of 87.0%. Colourless and white eye (w) showed no allelism
between re, bw and w although there did seem to be some complementation between bw and w.
) ‫أنموذج ( أ ) الخاص برسائل الماجستير و اطاريح الدكتوراة ( اخر شهادة‬
Effect of X- irradiation on meiotic drive at the D locus and on
recombination M – re Meiotic drive showed no sign of response to
2000 – 4000 r X-rays, no significant difference in sex ratio being
observed between the progeny of irradiated and control RD males.
Selection for low recombination between M and re in the progeny of
X-irradiated pupae, gave some response in one line but this was lost
because of associated low fertility. Such variation as was observed in
M-re recombination and sex ratio in the progenies of irradiated
males was also observed in the controls suggesting the effect could
not be due to the radiation but to natural variation or other factors.
Variation in recombination M/m-re Linkage distance between M/m
and re on chromosome 1 has been investigated. It varied between
strains being higher in an ACCRA line than in T-30 or MUAMSABU
lines. Considerably variation was observed between generations but
this seemed to be random. Recombination from T-30 single pair
mating was significantly lower than from mass mating but in ACCRA
there was no difference between the two kinds of mating. In
MWAMSABU there was significantly more male than female
recombinants but the other lines showed no such difference.
Recombination varied between families and the variation appeared
to be discontinuous falling into a Polymodal distribution.