Question

According to the gene for gene hypothesis by floor 1956 the resistance of a host is governed by dominant jeans and the Reliance of a pathogen by a recessive jeans when genes in the host and pathogen match for all the Loki then only the host will show suspectable reaction if some low C remain unnated the host will show resistant reaction determine the disease reaction in the following types.

	Host genotype	Pathogen genotype	Disease reaction
(i)	AA	Aa
(ii)	BB	Bb
(iii)	AABB	Aa or Bb
(iv)	AABBCC	aabb

• A. Susceptible, Susceptible, Resistant, resistant
• B. Susceptible, Resistant, Susceptible, Resistant
• C. Resistent, Resistant, Susceptible, Susceptible
• D. Resistant, Susceptible, Resistant, Susceptible

Answer 1

Answer:

C. Resistent, Resistant, Susceptible, Susceptible

• Based on the gene-for-gene hypothesis by Flor (1956), here are the disease reactions for each combination:

(i) Host: AA, Pathogen: Aa -> Resistant

Since the host has the dominant gene AA, it will resist the pathogen.

(ii) Host: BB, Pathogen: Bb -> Resistant

The host has the dominant gene BB, so it will resist the pathogen.

(iii) Host: AABB, Pathogen: Aa or Bb -> Susceptible

The host has dominant genes AABB, but the pathogen has recessive genes Aa or Bb that match some of the host's genes, so the host will be susceptible.

(iv) Host: AABBCC, Pathogen: aabb -> Susceptible

The host has dominant genes AABBCC, but the pathogen has recessive genes aabb that match none of the host's genes, however since the pathogen has recessive genes for all the loci, the host will still be susceptible.

So, the correct disease reactions are: Resistant, Resistant, Susceptible, Susceptible.