What is the Difference Between Complete and Incomplete Dominance

, , No Comments



Complete DominanceIncomplete Dominance
F1 is similar to dominant parent.F1 is different from either of the two parents.
Phenotypic ratio = 3 : 1Phenotypic ratio = 1 : 2 : 1
Genotypic ratio = 1 : 2 : 1
Phenotypic ratio ≠ Genotypic ratioPhenotypic ratio = Genotypic ratio
In F1 dominant trait expresses fullyIn F1 dominant trait is incompletely expressed
One dominant allele is enough to express dominant traitTwo alleles are required to fully express dominant trait
Examples:
Humans (Hairy is dominant over Baldness);
Blood group Allele A is dominant over blood group O
Examples:
Mirabilis Jalapa;
Snapdragon - Antirrhinum Majus

Gene Interactions

Both the Complete and Incomplete Dominance are the Intragenic (Allelic) Gene Interaction. The other types are:
  • Intragenic (Allelic) Gene Interaction
  • Intergenic (Non-Allelic) Gene Interaction
    • Epistasis
    • Duplicate Genes
    • Complementary Genes
    • Supplementary Genes
    • Polymeric Genes
    • Pleiotropy
    • Polygenic Genes

Incomplete Dominance

In the case of Incomplete Dominance, dominant allele do not completely express itself, resulting in a different phenotype. F1 generation expresses a phenotype which is intermediate between those of the parent.

Carl Correns discovered incomplete dominance and cytoplasmic dominance.

Definition of Incomplete Dominance

Incomplete dominance is a type of Gene interaction, in which, in a heterozygous condition, both alleles of a gene at a locus are partially expressed, often resulting in an intermediate (or different) phenotype. It is also called partial dominance.


Complete Dominance

In the case of Complete Dominance, dominant allele completely express itself, thereby masking the effect of Recessive allele, resulting in a dominant phenotype. F1 generation expresses a phenotype which is dominant between the parents.

Definition of Complete Dominance

Complete dominance is a type of Gene interaction, in which, in a heterozygous condition, the dominant allele of a gene at a locus is fully expressed, supressing the recessive allele, resulting in a dominant phenotype.

Multiple Choice Questions

In F2 generation, we observe the phenotypic ratio = 3 : 1. Which of the following conclusion would be correct?
(1) Trait = 2, Dominance = Complete
(2) Trait = 1, Dominance = Incomplete
(3) Trait = 1, Dominance = Complete
(4) Trait = 2, Dominance = Incomplete

Ans: http://zoomgenetics.apphb.com/?id=m39

In F2 generation, we observe the phenotypic ratio = 1 : 2 : 1. Which of the following conclusion would be correct?
(1) Trait = 2, Dominance = Complete
(2) Trait = 1, Dominance = Incomplete
(3) Trait = 1, Dominance = Complete
(4) Trait = 2, Dominance = Incomplete

Ans: http://zoomgenetics.apphb.com/?id=m40


ZoomGenetics is a software for learning genetics for students preparing for AIPMT, AIIMS, JIPMER, PMT and other medical entrance exams. Zoom Genetics covers a major portion of about 25 to 30% of the syllabus of Biology for the students preparing for Medical Entrance Examination.

The unique features are zooming user interface, extensive graphics, bulleted notes, easy to understand description, info-graphics, memory techniques, and extensive multiple choice questions.

Free Download:  ZoomGenetics Software (For Windows) to "Boost your Biology" Score in Medical Entrance Exams.

0 comments:

Post a Comment