Development in drosophila
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The document is a seminar synopsis on the development of Drosophila melanogaster, highlighting its significance as a model organism in genetics and developmental biology. It covers various topics including Drosophila's physical appearance, life cycle, genetic markers, and cell biology of its development, along with discussions on sex determination and chromosome aberrations. The seminar concludes with the importance of Drosophila in understanding developmental processes and its relevance to human genetics.
![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.](https://image.slidesharecdn.com/4-200503075414/85/Development-in-drosophila-7-320.jpg)
Development in drosophila
- 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.
- 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)