Question

Drosophila with the genotype AAA+XX is?
A. Normal male
B. female
C. Intersex
D. Metamale

Answer 1

Hint: Drosophila melanogaster displays the sex chromosome nature of XY male and XX female. The process of sex determination in Drosophila, however, is somewhat distinct from that of humans

Complete step by step answer:
First we should know about Genic Balance Theory to answer this question. C.B. suggested the Genic Equilibrium Hypothesis. Bridges in Drosophila for sex differentiation in 1922. Living species with very little standards are, depending on their morphological physiological and behavioural features, divided between male and female individuals. In mammals, the Y chromosome is the main chromosome that determines sex. The presence of a single chromosome, ineluctable to the number of chromosomes, begins male sex production in human embryos.
Now, let us find the solution from the options-
- For normal females, the X / A value is 1.0, and for normal males, it is 0.5. Thus, option A is not the correct option.
- According to this sex determination hypothesis, if the X chromosome ratio becomes > 1 to the total number of autosome sets (X / A), the person would be super female. Thus, option B is not the correct option.
- It says that the ratio of the X-chromosome number to that of the whole autosome group decides the sex of Drosophila. If the ratio of the X allele to the total number of autosomal sets (X / A) ranges between 1 and 0.50, the intersex condition is indicated by the genotype. Drosophila has 3 autosomes and 2 X chromosomes, as per the question, making the X / A ratio 0.66, i.e. the intersex genotype.
- Lower viability Drosophila fruit fly with a male phenotype is a metamale (or supermale) wherein the ratio of X chromosomes to autosome sets (A) is far less than 0.5. Thus, option D is not the correct option.

Thus, the correct answer is option (C) Intersex.

Note:
There are 8 genes, three sets of autosomes and one set of sex chromosomes in Drosophila. The ratio of the number of X chromosomes with that of the number of autosomal sets decides the sex in Drosophila.