Exploring a Novel Genetic Interaction—Intergenic or Non-Allelic Interaction: The Case of Blood Groups and the Bombay Phenotype
A Study by Harshita Motvani, Medical Enthusiast, Batch 2025-2026
🧠✨ Classroom Discovery Highlight:
This insightful genetic analysis was born from an engaging classroom discussion, where curiosity sparked collaboration. The discovery highlights the true value of attentiveness in academic settings. Harshita Motvani’s contribution is a testament to how interactive learning can inspire original thought, deepen understanding, and lead to meaningful breakthroughs.
This insightful genetic analysis was born from an engaging classroom discussion, where curiosity sparked collaboration. The discovery highlights the true value of attentiveness in academic settings. Harshita Motvani’s contribution is a testament to how interactive learning can inspire original thought, deepen understanding, and lead to meaningful breakthroughs.
Genetic Cross: HH Iᴬi × hh Iᴬi
Interspecific Interaction:
It refers to the interaction between different genes located at different loci, influencing a single trait. These genes can affect the expression of each other in various ways.
Epistasis:
Epistasis is a form of gene interaction where one gene masks or modifies the expression of another gene at a different locus. In this case, the H gene is epistatic to the ABO gene — if hh genotype is present, it prevents the expression of the ABO alleles, resulting in the Bombay phenotype.
Punnett Square (F₂ Generation):
| × | HIᴬ | Hi | hIᴬ | hi |
|---|---|---|---|---|
| HIᴬ | HH IᴬIᴬ A |
HH Iᴬi A |
Hh IᴬIᴬ A |
Hh Iᴬi A |
| Hi | HH Iᴬi A |
HH ii O |
Hh Iᴬi A |
Hh ii O |
| hIᴬ | Hh IᴬIᴬ A |
Hh Iᴬi A |
hh IᴬIᴬ Bombay |
hh Iᴬi Bombay |
| hi | Hh Iᴬi A |
Hh ii O |
hh Iᴬi Bombay |
hh ii Bombay |
Phenotypic Ratio:
9 A : 3 O : 4 Bombay → 12 Normal : 4 Bombay (3:1)
9 A : 3 O : 4 Bombay → 12 Normal : 4 Bombay (3:1)