Question

Which of the following is NOT a characteristic that makes Drosophila an ideal model organism?

	A.	Large numbers of offspring.
	B.	Easily manipulated in a laboratory.
	C.	Many well defined variations and mutations.
	D.	Long generation time.

Answer 1

Answer) long generation time

Note: the question had asked for characteristics which is not present in Drosophila as a model organism.

EXPLANATION

Drosophila is an important model organism. It is most powerful tool for genetics for analyzing the various physiological characteristics based on mutation and manipulation in the genome . About 60% of gene in Drosophila is linked to human genetic disorders. It has rapid generation time. Each female fly can lay up to ∼100 eggs per day for up to 20 days. It takes approximately 10 days at 25 °C for an embryo to develop into a fertile adult fly. Thus it is relatively easy to generate large numbers of embryos or flies for an experimental approach if required.

The life cycle includes 4 distinct stages: egg, larva, pupa and adult.

Life cycle:

The eggs, are about 0.5 mm long, hatch after 12–15 hours (at 25 °C or 77 °F).The resulting larvae grow for about 4 days (at 25 °C) while molting twice (into second- and third-instar larvae), at about 24 and 48 h after hatching.During this time, they feed on the microorganisms that decompose the fruit, as well as on the sugar of the fruit itself. The mother puts feces on the egg sacs to establish the same microbial composition in the larvae's guts that has worked positively for herself. Then the larvae encapsulate in the puparium and undergo a 4-day long metamorphosis (at 25 °C), after which the adults emerges.

Drosophila is known as a " genetic workhouse". The manipulation in the genome of drosophila is relatively simple thus help to generate transgenic flies carrying DNA that activates or inhibits the expression of individual genes of interest, either throughout the organism or in defined tissues.

From all this it can be concluded drosophila as a versatile model organism.