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CBSE - X - Biology - Heredity and Evolution

Please explain

Asked by Annette 13th March 2010, 3:04 PM
Answered by Expert


The inheritance of traits are controlled by factors called genes. Each gene is present in more than one form  called alleles or allelomorphs. Each pair of alleles will have a dominant allele and a recessive allele. In the presence of the dominant gene, the recessive gene will never express itself. Only if both the alleles are recessive, the recessive trait will be exhibited.

For example - In case of pea plants, the plant will be tall if one or both genes for tallness i.e. TT or Tt are present. However the plant will be dwarf only if both the recessive genes i.e. tt are present.

Answered by Expert 15th March 2010, 4:38 PM

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