Explanation

Genic Balance Theory of Sex The theory of genic balance given by Calvin Bridges (1926) states that instead of XY-chromosomes sex is determined by the genic balance or ratio between X-chromosomes and autosome genomes The theory is basically applicable to Drosophila melanogaster over, which bridges worked. He found that the genic ratio X IA of 1.0 produces fertile females whether the files have XX + 2A or XXX + 3A chromosome complement. A genic ration (X I A) of 0.5 forms a male fruitfly. This occurs in XY + 2A as well as XO + 2A Chromosome Complement X/A Ratio Sexual Morphology X X X + 2A X X X + 3A X X + 2A X X + 3A X X X +4A X O + 2A X Y +2A 3/2 or 1.5 3/3 or 1.0 2/2 or 1.0 2/3 or 0.67 3/4 or 0.75 1/2 or 0.5 1/2 or 0.5 Metafemale Female Female Inter sex Inter sex Male Male X Y +3A 1/3 or 0.33 Metamale