Name: Sex Determination (Drosophila melanogaster)
Uploaded: 2019-07-19
Duration: 7 min 20 s
Description: Drosophila melanogaster or the common fruit fly has contributed a lot to genetics. One of them is its sex determination system with more than five types of s...

Question

Explain co-dominance and incomplete dominance with examples.

Accepted Answer

Incomplete dominance is when the phenotypes of the two parents blend together to create a new phenotype for their offspring. For example, Monohybrid cross was done between the red and white coloured flowers of Snapdragon plant. Consider, pure breed of the red flower has RR pair of alleles and that for the white flower is rr. The F1 generation produced a pink coloured flower with Rr pair of alleles. The reason for this variation is the incomplete dominance of the allele R over the allele r. This led to the blending of colour in flowers.

Codominance shows a type of inheritance pattern where both the alleles of a gene pair are completely expressed in a heterozygote. Heterozygous alleles carry different information on traits. When we say one trait is dominant over the other, there can be two reasons:

Either it is non-functional

Less active than the normal allele. For example, ABO blood grouping in humans. When a cross between parent with AB group and O group, the possible combinations are:

Explain co-dominance and incomplete dominance with examples.

Important Questions on Principles of Inheritance and Variation

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