Class 12 · Principles of Inheritance and Variation

Genotype vs Phenotype Expression — NEET Biology

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If we use alphabetical symbols for each gene, then the capital letter is used for the trait expressed at the F1 stage and the small alphabet for the other trait. For example, in case of the character of height, T is used for the Tall trait and t for the 'dwarf', and T and t are alleles of each other. Hence, in plants the pair of alleles for height would be TT, Tt or tt. Mendel also proposed that in a true breeding, tall or dwarf pea variety the allelic pair of genes for height are identical or homozygous. TT and tt, respectively. TT and tt are called the genotype of the plant while the descriptive terms tall and dwarf are the phenotype. What then would be the phenotype of a plant that had a genotype Tt?

NCERT Biology · Class 12 · Chapter 4 · Paragraph 18
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Which of the following statements are NOT correct about a heterozygous genotype (e.g., Tt) in the context of Mendelian genetics? S1: A genotype such as Tt, controlling a single character, is accurately referred to as a monohybrid. S2: When a heterozygous Tt plant is crossed with a homozygous dominant TT plant, it yields a 3:1 phenotypic ratio (tall:dwarf). S3: According to the Law of Segregation, a heterozygous individual produces two distinct types of gametes in equal proportions. S4: Self-pollination of a heterozygous Tt plant will invariably produce uniform tall plants in the F2 generation. S5: The phenotype of a heterozygous genotype is typically identical to that of the homozygous dominant genotype in cases of complete dominance.

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