Question

Dominance deviations are interactions

• A. Within alleles
• B. Between loci
• C. Within locus
• D. Breeding values

Hint:

Genetic Interaction Types:
Dominance Deviations = Interactions WITHIN LOCUS (Intralocus allelic interaction).
Epistasis = Interactions BETWEEN LOCI (Interlocus interaction).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Partitioning of genetic variance: dominance deviation ($V_D$) represents non-additive intralocus allelic interactions (within a single locus), whereas epistasis ($V_I$) represents interlocus interactions (between different loci).
Key Formula or Approach:
\[ \text{Genetic Variance: } V_G = V_A + \underbrace{V_D}_{\text{Interaction WITHIN Locus}} + \underbrace{V_I}_{\text{Interaction BETWEEN Loci (Epistasis)}} \]

Step 2: Detailed Explanation:
In quantitative genetic theory (Fisher 1918, Falconer):
- Total genotypic value ($G$) is partitioned into additive breeding value ($A$), dominance deviation ($D$), and epistatic interaction ($I$):
1. Dominance Deviations ($D$ $V_D$): Represent non-additive allelic interactions occurring Within a Single Locus (Within locus) between homologous maternal and paternal alleles (allelic dominance, overdominance).
2. Epistatic Deviations ($I$ $V_I$): Represent non-additive genetic interactions occurring Between different gene loci (Between loci) (additive $\times$ additive, additive $\times$ dominance, etc.).
Therefore, dominance deviations are interactions within locus.

Step 3: Final Answer:
Thus, dominance deviations are interactions Within locus, corresponding to option (C).