This document discusses gene interactions and their mechanisms. It describes how genes interact with each other and the environment to influence phenotypes. The main types of gene interactions are allelic, including complete dominance, incomplete dominance and co-dominance, and non-allelic, such as additive, duplicate, dominant suppression, dominant and recessive epistasis. Examples are provided for each type of interaction.

1. Aditi J. Lakkad
BO118202
2nd Semester M.Sc.
DOS in Botany, UOM

2. CONTENTS
• INTRODUCTION
• GENE INTERACTION
• TYPES OF GENE INTERACTIONS
• MECHANISM OF GENE INTERACTION
• EXAMPLES
• SUMMARY
• REFERENCES

3. INTRODUCTION
• Johann Gregor Mendel (1822–1884) was a lifelong
learner, teacher, scientist, and man of faith.
• In 1865, Mendel presented the results of his experiments
with nearly 30,000 pea plants to the local natural history
society.

4. INTRODUCTION
• Mendel’s laws of inheritance
– Law of Dominance
– Law of Segregation
– Law of Independent Assortment
• One gene determines one trait

5. GENE INTERACTION
• The contribution of
genes to the
phenotypic character
are modified by
interactions with
other genes and
environment.
• The works of Bateson
and Punnett gave
early examples of
gene interactions.

6. GENE INTERACTION
• Types of gene interaction-
Gene-Gene and Gene-Environment
– Interaction between allelic genes
• Complete dominance
• Incomplete dominance
• Co-dominance
– Interaction between non-allelic genes
• Additive gene interaction
• Duplicate gene
• Dominant suppression
• Dominant epistasis
• Recessive epistasis

7. MECHANISM OF GENE
INTERACTION
• Genes are segments of DNA
that code for particular
polypeptide in the form of a
specific sequence of its base
pair.
• Proteins are the end products
of gene expression, and so gene
interactions are interactions between proteins that
are controlled by these genes.

8. MECHANISM OF INTER-ALLELIC
GENE INTERACTION

9. ADDITIVE GENE INTERACTION
Eg: Lentil seed color

10. COMPLEMENTARY GENE
ACTION
Eg: Flower Color in Sweet Pea

11. RECESSIVE EPISTASIS
Eg: Coat Color In Mice

12. DOMINANT EPISTASIS
Eg: Fruit Color in Summer Squash

13. DOMINANT SUPPRESSION/
INHIBITORY FACTOR
• Eg: Leaf color in Rice

14. DUPLICATE GENE INTERACTION
Eg: Capsule Shape in Shepherd’s purse

15. POLYMORPHIC GENES
Eg: Awn length in barley

16. GENE INTERACTION WITH THE
ENVIRONMENT
Eg: Coat Color Of Siamese cat

17. SUMMARY

19. REFERENCES
• Charles Molnar and Jane Gair, Concepts of Biology-1st
Canadian Edition, The B.C. Open Textbook Project, Pp- 265-
303.
• Gardner, M. J. Simmons, D. P. Snustad, PRINCIPLES OF
GENETICS, 8TH ED, John Wiley & Sons, 2006, Pp- 33-35.
• D. J. Cove, Genetics, CUP Archive, 30-Nov-1971, Pp- 45-57.
• B N Behera, Genetics through Problems, Sarup & Sons, 2004 ,
Pp- 45-47.
• https://www2.estrellamountain.edu/faculty/farabee/biobk/
BioBookgeninteract.html
• http://www.biologydiscussion.com/genetics/gene-
interactions/gene-interactions-allelic-and-non-allelic-cell-
biology/38795