Question

In corn, small pollen (sp) is recessive to normal pollen (sp+) and banded necrotic tissue, called zebra necrotic (zn), s ssive to normal tissue (zn+). The genes that produce these phenotypes are closely linked on chromosome 10. If no crossing over occurs between these two loci, give the types of progeny expected from the following cross: sp zn sp znx sp zn xspzn b.

Answer 1

Answer:

Option B

Explanation:

Please see the attached image

Given -

Allele for small pollen is "sp"

Allele for normal pollen is "sp+"

and "sp+" is dominant over "sp"

Allele for zebra necrotic tissue is "zn"

Allele for normal necrotic tissue is "zn+"

and "zn+" is dominant over "zn"

Cross is carried out between

sp+ sp zn+ zn x sp+ sp zn+ zn

The gametes of the parent cells are -

sp+ zn+, sp+zn, spzn+, spzn

The cross would be as follows

         

sp+ zn+ sp+zn spzn+ spzn

sp+ zn+ sp+ sp+ zn+ zn+sp+ sp+ zn+ znsp+ sp zn+ zn+ sp+ spzn+ zn  

sp+zn sp+ sp+ zn+ znsp+ sp+ zn znsp+ sp zn+ zn sp+ sp zn zn

spzn+ sp+ sp zn+ zn+sp+ sp zn+ znsp sp zn+ zn+ sp sp zn+ zn

spzn sp+ sp zn+ zn sp+ sp zn zn sp sp zn+ zn sp sp zn zn

Hence, option B is correct