Q. Sex determination ratio in an organism is given by , then organism will be:

 2011  207 Bihar CECEBihar CECE 2001 Report Error

Solution:

In Drosophila the presence of Y-chromosome has been found essential for the fertility of male sex but that has nothing to do with the determination of male sex, here the sex is determined polygenic ally. Ratio of X-chromosomes to autosomes and corresponding sex type In Drosophila melanogaster.
X chromosomes (X) and sets of autosomes
Rato X/A
Sex-type
IX 2A
0.5
Male
2X 2A
1.0
Female
3X 2A
1.5
Metafemale
4X 3A
1.33
Metafemale
4X 4A
1.0
Tetraploid female
3X 3A
1.0
Triploid female
3X 4A
0.75
Intersex
2X 3A
0.67
Intersex
2X 4A
0.5
Tetraploid male
IX 3A
0.33
Metamale