Question

Which type of Drosophila is produced, if (AA + X) ovum fertilizes with (A + Y) sperm?
A. 0.67, sterile
B. 0.67, Intersex sterile
C. 0.5, Normal male
D. 0.33, Super male sterile

Answer 1

Hint: In Drosophila, the sex determination is not based on sex chromosomes but it is based on the ratio of X chromosomes to the sets of autosomes. In Drosophila, there are 4 chromosomes, i.e. n=4. When ovum (AA+X) fertilized with sperm (A+Y), it will produce offspring with genotype AAA+XY.

Hermaphrodite is an individual who has female characteristics in one part of the body and male characteristics in other parts. They are the result of the loss of an X chromosome from the cell during the first mitotic division of the zygote. ...That the Y chromosome has no role in sex determination in Drosophila.

Complete answer:
Drosophila melanogaster: The widely used model organism. It has obvious advantages in ageing research, including short life span (an average life span of 2-3 months), low maintenance requirements, abundant genetic resources and easy genetic manipulation.
More importantly, more than 50% of the Drosophila genes with human homology have been completely sequenced In addition, more than 75% of known human disease genes covering a wide range of diseases have fly homologs. These characteristics make Drosophila an ideal model organism for studying ageing mechanisms and developing effective ageing interventions, which are related to human ageing research.
Solve:
XXAA (diploid) X: A ratio = 1 Female
XYAA/X0AA (diploid) X: A ratio = 0.5 Male/sterile male
XXYAAA (aneuploid) X: A ratio = 0.67 Intersex
XXXAAA (aneuploid) X: A ratio = 1 Female
XYYAAA (aneuploid) X: A ratio = 0.33 Super male sterile
In this, the X: A ratio is 0.33. Hence, it will produce super male sterile.
Thus, the option (D) is correct.

Note: The fruit fly (Drosophila melanogaster) is a fully metabolized insect and therefore has undergone a complete metamorphosis. Their life cycle is divided into four stages: embryo, larva, and adult. The eggs are about 0.5 mm long and hatch at 12-15 hours (25°C or 77°F).