INTRODUCTION ABOUT DROSOPHILA PHYSICAL APPEARANCE CELL BIOLOGY OF DROSOPHILA DEVELOPMENT LIFE CYCLE THE DROSOPHILA GENOME UNUSAL FEATURES OF DROSOPHILA SEX DETERMINATION GENETIC MARKERS DEVELOPMENT IN DROSOPHILA CLEAVAGE THE ORIGINS OF ANTERIOR-POSTERIOR POLORITY {GENES} CHROMOSOME ABERRATIONS CONCLUSIONS REFERENCES

1. SEMINAR ON
Development in Drosophila
By
KAUSHAL KUMAR SAHU
Assistant Professor (Ad Hoc)
Department of Biotechnology
Govt. Digvijay Autonomous P. G. College
Raj-Nandgaon ( C. G. )

2. SYNOPSIS:-
• INTRODUCTION
• ABOUT DROSOPHILA
• PHYSICAL APPEARANCE
• CELL BIOLOGY OF DROSOPHILA DEVELOPMENT
• LIFE CYCLE
• THE DROSOPHILA GENOME
• UNUSAL FEATURES OF DROSOPHILA
• SEX DETERMINATION
• GENETIC MARKERS
• DEVELOPMENT IN DROSOPHILA
• CLEAVAGE
• THE ORIGINS OF ANTERIOR-POSTERIOR POLORITY {GENES}
• CHROMOSOME ABERRATIONS
• CONCLUSIONS
• REFERENCES

3. INTRODUCTION:-
• Kingdom:Animalia
• Phylum:Arthropoda
• Class:Insecta
• Order:Diptera
• Family:Drosophilidae
• Genus:Drosophila
• Subgenus:Sophophora
• Species group:melanogaster group
• Species subgroup:melanogaster subgroup
• Species complex:melanogaster complex
• Species:D. melanogaster
• Binomial name:Drosophila melanogaster
•

4. ABOUT DROSOPHILA:-
• Drosophila melanogaster is a fruit fly a little insect
about 3mm long which accumulates around spoiled
fruits its is also one of the most valuable of organisms
in biological research , particularly in genetics and
developmental biology.
• Drosophila has been used as a model organism for
research for almost a century and today several
thousand scientists are working on many different
aspects of fruit fly.
• Thomas Hunt Morgan began using fruit flies in
experimental studies of heredity at Columbia
University in 1910.

5. PHYSICAL APPEARANCE:-
• Wildtype fruit flies are yellow-brown, with brick red
eyes and transverse black rings across the
abdomen(the part of the body containing digestive
organs.).
• They exhibit sexual dimorphism: females are about
2.5 millimeters (0.098 in) long; males are slightly
smaller with darker backs.
• Males are easily distinguished from females based on
color differences, with a distinct black patch at the
abdomen.

6. Males and females
XY or X0 male
X/A ratio 0.5
XX female
X/A ratio 1

7. CELL BIOLOGY OF DROSOPHILA
DEVELOPMENT :-
• Gamete:- A mature haploid insect germ cell
which able to unite with another of the opposite
sex in sexual reproduction to form a zygote.
• Embryo:- An unborn offspring in process of
development[the part of insect develops into new
insect.]
• Larva:- An active immature form of an insect that
undergoes metamorphosis.
• Pupa:- An insect in its inactive immature form
between larva and adult.

8. Cell Biology of Drosophila
Development

9. LIFE CYCLE:-
The Drosophila life cycle represents the differentiation of
two distinct forms: the larva and the Imago (adult).
Embryogenesis: differentiation
of the larva
Metamorphosis
:
differentiation
of the imago
(adult).
Imaginal cells are the cells
of the adult or imago.
Kalthoff 2001

10. THE DROSOPHILA GENOME:-
• Drosophila has four pairs of chromosomes
• x/y sex Chromosomes.
• autosomes:-
• 2 and 3 - large metacentric chromosome.
• 4 - very small telocentric chromosome.
• The size of genome is about 165 million bases and
contains estimated 14,000 genes.Thus development
can be define as the formation of different types of
tissues , organs , cells .

11. UNUSUAL FEATURES OF DROSOPHILA:-
• they increase in size and become polyploid.
• the many chromosome strands line up to form the
giant polytene chromosomes(mapping physical
location of genes & banding pattern) that give
Drosophila it’s wonderful cytogenetics{study of
inheritance in relation to structure of
chromosome.}.

12. SEX DETERMINATION:-
• X Chromosome Autosomes Ratio of X:A Sex
XXXX AAAA 1 normale female
XXX AAA 1 normal female
X X AA 1 normal female
X AA 0.50 male
XXX AA 1.50 super female
XXXX AAA 1.33 super female
XX AAA 0.66 intersex
X AAA 0.33 super male
 1=female; 0.5=male; above 1=super female; between 0.5 -
1=intersex; below 0.5=super male.

13. GENETIC MARKERS:-
• Cy 1 := Curly; The wings curve away from the
body.
• e1: =ebony; Black body and wings.
• Sb1:= stubble; Bristles are shorter and thicker.
• w1:= white; Eyes lack pigmentation and
appear white.
• y1: =yellow; Body pigmentation and wings
appear yellow.

14. DEVELOPMENT IN DROSOPHILA:-
• - Most insect eggs undergo superficial cleavag wherein a large
mass of centrally located yolk confines cleavage to the cytoplasmic
rim of the egg.
• The zygote nucleus undergoes several mitotic divisions
• within the central portion of the egg. In Drosophila, 256 nuclei are
produced by a series of eightnuclear divisions averaging 8 minutes
each.
• During the ninth division cycle, about five nuclei reach the surface
of the posterior pole of the embryo.These nuclei become enclosed
by cell membranes and generate the pole cells that give rise to the
gametes of the adult.
• At cycle 10 and then undergo four more divisions at progressively
slower rates. During these stages of nuclear division, the embryo is
called a syncytial blastoderm.

15. • When the nuclei reach the periphery of the
egg during the tenth cleavage cycle, The
nuclei and their associated cytoplasmic islands
are called energids.microtubule domains in
prophase of the twelfth mitotic division.
• cycle 13, the oocyte(process formation of
zygote) plasma membrane folds inward
between the nuclei,eventually partitioning off
each somatic nucleus into a single cell This
proces screates the cellular blastoderm.

17. • The expressed in the mother's
ovaries produce messenger RNAs that are placed in
different regions of the egg. These messages encode
transcriptional and translational regulatory proteins that
diffuse through the syncytial blastoderm and activate or
repress the expression ofcertain zygotic genes.
• Two of these proteins, , regulate the
production of anterior structures, while another pair of
maternally specified proteins,
regulates the formation of the posterior parts of the
embryo.

18. • the zygotic genes regulated by these maternal factors are expressed in
certain broad (about three segments wide), partially overlapping domains.
These genes are called (because mutations in them cause gaps
in the segmentation pattern).
• Differing concentrations of the gap gene proteins cause the
transcription of , which divide the embryo into periodic
units.
• The transcription of the different pair-rule genes results in a striped
pattern of seven vertical bands perpendicular to the anteriorposterior
axis. The pair-rule gene proteins activate the transcription of the
, whose mRNA and protein products divide the embryo
into 14 segment-wide units.
 the , whose transcription determines the
developmental fate of each segment.

20. THE SEGMENTATTION GENE:-

23. After the segmental boundaries have been established,the characteristic
structures of each segment are specified. This specification is accomplishe by
the homeotic selector genes.

24. CHROMOSOME ABERRATIONS:-
• Aberrations:- Change with chromosome.
• 1:- Duplication
• 2:- Delition
• 3:- Translocation
• 4:-Inversion

25. -
:-
• a b c d e f g a b c d de de f g
• a b c d e f g a b c d de de f g
:-
• a b c de ed f g
• a b c ed de f g
:-
• a b c d e f g a b c d e f d e g

26. • 1:- Delition:- Loss of a part of chromosome in
loop form.
• 2:-Terminal delition:- Side chromosome
deleted.
• 3:-Interminal delition:- Anything is deleted.
• a b c d a b c d
• a b c d a b c d

27. .
• a b c d
• a b c d
• 1 2 3 4
• 1 2 3 4
.
• a b c d
• a b 3 4
• 1 2 c d
• 1 2 3 4

28. :-
1 5 4 3 2 6 7 8 9 10 11
1 8 7 6 5 4 3 2 9 10 11
1 2 3 4 5 6 7 8 9 10 11
Paracentric Inversion
Pericentric Inversion
1 2 3 4 5 6 7 8 9 10
1 2 7 6 5 4 3 8 9 10
1 2 3
4
5
6
7
8 9 10

29. When the gene is deleted, the third thoracic
segment becomes transformed into another second thoracic
segment. The result is a fly with four wings.

30. In the recessive mutant of the gene fails to be
expressed in the second thoracic segment, and antennae
sprout out of the leg positions .

31. CONCLUSIONS:-
• Drosophila has been a particularly valuable model
system for developmental studies.
• It can be used to study development, physiology only
have functions in multicellular organism.
• 90 years of genetics it is a valuable model system.
• Drosophila is so popular & it was mostly used in
genetics,developmental biology etc.
• The D. melanogaster lifespan is about 30 days at 29 °C
(84 °F).
• About 75% of known human disease genes have a
recognizable match in the genome of fruit flies .

32. REFERENCES
• Development biology Scott F. Gilbert.
• www.kbiotech.com 23sep
(08:00 PM)
• www.answerforyou 22sep
(03:30 PM)