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Principles Of Inheritance And Variation

Question
CBSEENBI12000248

Explain how a test cross can be conducted to distinguish between a homozygous and heterozygous dominant genotype.

Solution
Test Cross. When an individual is crossed to recessive parent called test cross. The results can be easily analysed to determine whether the individual is  homozygous or heterozygous
If we cross a dominant individual with its recessive parent then we can determine from  the results the genotype of the individual.
If all progeny are like their dominant parent then the the individual must be a homozygous. Like in the diagram all the progeny are having Violet flowers
If 50% of the progeny are like the dominant prent and the other are like the recessive parent then individual must be heterozygous. Like in the diagram 50 % have violet flowers and 50 % have white flowers.

Fig. A test cross can be conducted to differentiate between a homozygous and heterozygous dominant genotype.