Describe Mendel’s Monohybrid experiment.

If we use alphabetical symbols for each gene then the capital letter is used for the trait expressed at the $F_{1}$ stage and the small alphabet for the other trait.

For example, in case of the character of height ' $\mathrm{T}$ ' is used for the Tall trait and ' $\mathrm{t}^{\prime}$ for the 'dwarf' and ' $\mathrm{T}$ ' and ' $\mathrm{t}$ ' 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 $\mathrm{tt}$ respectively.

$TT$ and $\mathrm{tt}$ are called genotype of the plant while the descriptive terms tall and dwarf are the phenotyped.

As Mendel found the phenotype of the $F_{1}$ heterozygote $\mathrm{Tt}$ to be exactly like $TT$ parent in appearance he proposed that in a pair of dissimilar factors, one dominates the other (as in the $F_{1}$ ) and hence is called the dominant factor while the other characters/trait pairs that he studied.