Incomplete Dominance is an Intragenic (Allelic) Gene Interaction, where there is no clear-cut dominant-recessive relationship between the two alleles of a gene. Both the alleles express partially, often creating an intermediate phenotype. Example: Pink flower in Mirabilis Jalapa, when crossed with Red and White flower plants.
Co-Dominance is also an Intragenic (Allelic) Gene Interaction, where both the co-dominant alleles express fully, causing a mixture of effects in the resulting phenotype. Example: Roan Character in cattle and Blood Group (AB) which is the resulting phenotype of (A) and (B) alleles of blood group. ABO blood group system displays the three gene interactions - Complete Dominance, Codominance and Multiple Alleles
Free Download ZoomGenetics Software (For Windows)
Practice Free MCQs: Free MCQs and Pictures
Table of Differences between Codominance and Incomplete Dominance
|Effect of one of the two alleles is more conspicuous.||Effect of both the alleles are equally conspicuous.|
|It produces a fine mixture of the expression of two alleles.||There is no mixing of the expression of two alleles.|
|The effect in hybrid is intermediate of the two alleles.||Both the alleles produce their effect independently.|
|The expressed phenomenon is new. It has no allele of its own.||The expressed phenotype is combination of two phenotypes and their alleles.|
|The incomplete dominant allele has quantitative effect.||The quantitative effect is absent.|
|Examples: Mirabilis Jalapa; Snapdragon||Examples: A and B blood group alleles of Human; Roan character in Cattle|
Gene InteractionsBoth the Complete and Incomplete Dominance are the Intragenic (Allelic) Gene Interaction. The other types are:
- Intragenic (Allelic) Gene Interaction
- Intergenic (Non-Allelic) Gene Interaction
- Duplicate Genes
- Complementary Genes
- Supplementary Genes
- Polymeric Genes
- Polygenic Genes
Multiple Choice Questions
ABO Blood group system is an example of (1) Complete dominance and multiple allele (2) Complete dominance and Lethal genes (3) Co-dominance and multiple allele (4) Incomplete dominance and multiple allele Ans: http://zoomgenetics.apphb.com/?id=m10
Which of the following is FALSE, if DA = Dominant Allele RA = Recessive Allele CA = Co-Dominant Allele DP = Dominant Phenotype RP = Recessive Phenotype (1) DA + RA = DP (2) CA + RA = DP (3) CA + RA = RP (4) RA + RA = RP Ans: http://zoomgenetics.apphb.com/?id=m16
`Inflated` pod shape in pea plant is a (1) Co-dominant allele (2) Dominant allele (3) Recessive allele (4) Multiple allele Ans: http://zoomgenetics.apphb.com/?id=m19
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.