Question

Write the types of sex-determination mechanisms the following crosses show. Give an example of each type.

(i) Female XX with Male XO 

(ii) Female ZW with Male ZZ

Answer 1

(i) Male heterogamety, Grasshopper. 

(ii) Female heterogamety, Birds

Detailed answer:

Sex determination mechanism in usually chromosome at and is of following type.

(1) XX-XY type found in mammals and some insects like Drosophila. 

(2) XX-XO type found in grasshoppers etc. 

(3) ZW-ZZ type found in Birds. 

(4) ZO-ZZ type found in butterflies etc. 

(a) Male heterogamety i.e., -- grasshopper 

(b) Female heterogamety - birds