This document discusses diabetes and the use of Drosophila melanogaster (fruit flies) as a model organism to study type 2 diabetes. It provides background on diabetes, describing it as resulting from insufficient insulin production or insulin resistance. It then outlines advantages of using fruit flies as a model, such as their short lifespan, sequenced genome, and ability to produce large numbers of offspring. Several genetic pathways involved in glucose intolerance in fruit flies are also discussed. The document concludes by suggesting future areas of research using the fruit fly model to study human diabetes genes and their functions.

1. Mohd Saifullah Ansari
M.Sc. (F) Genetics
Roll No. 15ZYM06
A.M.U.

2. Diabetes
 Insulin secretory dysfunction
 Insulin resistance (muscles, fat, liver)
 Increased endogenous glucose production
 Decreased incretin effect
 Deranged adipocytes biology

3. Insulin
 A polypeptide hormone secreted
by the β-cells of the pancreatic
islets.
STANDARD
METAPHOR
INSULIN
FUNCTION
HOMEOSTATIC
FUNCTION

4. Diabetes
Results from body’s failure to
produce insulin, and presently
requires person to inject
insulin
Results when pancreas does
not produce enough insulin to
control glucose level or the cells
not responding to insulin
Results when body of a
pregnant women does not
secrete excess insulin required
during pregnancy leading to
increased blood sugar level

5. Pathogenesis of type 2 diabetes

6. Present scenario of diabetes
 Worldwide 415 million cases (2015); expected to be 642
million (2040)
 In India, 69.1 million cases in 2015
 90% of cases are of type 2 DM
 In 2015, one in 11 adults was affected; expected to be one
in 10 adults in 2040
 In every 10 sec. one person dies from diabetes
 5.0 million deaths in 2015
(www.idf.org)

7. Organisms being used as diabetic model
MODEL
ORGANISMS
Keeshond Dog Biobreeding rat
NOD Mouse NZW Rabbit
D. melanogaster

8. Drosophila as a good model organism
SHORT LIFE
SPAN
GENOME
SEQUENCED
AVAILABILITY
OF MUTANTS
NO
ETHICAL
CONCERN
HOMOLOGOUS
FOR 70%
HUMAN
DISEASE GENES
LARGE NO.
OF
OFFSPRINGS
EASY TO
MAINTAIN
AND
MANIPULATE

9. Drosophila as a type 2 diabetic model
 Glucose level in fruit fly is controlled by ILPs, GLPs and
AKH.
 IPCs in adult synthesize Ilp2 , Ilp3 and Ilp5.
 Drosophila fat body stores and mobilizes energy reserves.
 Mutation of the Akh gene or gene encoding its receptor
(AkhR) , or the ablation of CC cells results in
severe obesity
hypoglycemia
lipid mobilization defects

10. Genetic pathways to glucose intolerance

11. Intrinsic regulators of ILPs output in Drosophila

12. Extrinsic regulators of ILPs output in Drosophila

13. Insulin resistance and feedback in Drosophila fat body cell

14. FUTURE DIRECTIONS
1. The development of new methods, such as for measuring
hormones in metabolic studies of feeding, fasting and
obesity in Drosophila.
2. The in vivo characterization of human diabetes
susceptibility genes and their mechanisms of function.
3. Studies of the evolution and development of glucose-
responsive insulin output.

15. References
 www.jax.org
 www.anim.med.kyoto
 dmm.biologist.org
 www.biologist.org
 www.elvesier.co.in
 wikipedia