*Genetic determinism of sexes
*Two types are known.
I. Drosophila met at mammals , insects and some plants.
a) Chromosomes have notation:
Masculine ⇒ xy
Feminine⇒xx
II. Abraxas met at amphibians,reptiles,birds and fish.
a) Chromosomes have notation:
Masculine⇒xx
Feminine⇒xy
