Describe Mendel's Monohybrid experiment.

Explanation

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 "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 genotype of the plant while the descriptive terms tall and dwarf are the phenotyped.

= As Mendel found the phenotype of the `F_1` heterozygote Tt to be exactly like TT parent in appearance he proposed that in a pair of dissimilar factors, one Parental dominates the other (as in the `F_1`) and hence is called the dominant factor while the other characters/trait pairs that he studied.
= It is convenient and logical to use the capital and lower case of an alphabetical symbol to remember this concept of dominance and fi generation
= Alleles can be similar as in the case of homozygotes TT and tt or can be dissimilar as in the case of heterozygote Tt।
= Since the Tt plant is heterozygous for genes controlling one character (height) it is a monohybrid and the cross between TT and tt is a monohybrid cross.
= From the observation that the recessive parental trait is expressed without any blending in the `F_2`
= generation, we can infer that when the tall and dwarf plant produce gametes by the process of meiosis the alleles of the parental pair separate or segregate from each other and only one allele is transmitted to gametes.
= This segregation of alleles is a random process and so there is a 50 percent chance of a gamete containing either allele as has been verified by the results of the crossings.
= In this way the gametes of the tall TT plants have the alleles .T. and the gametes of the dwarf tt plants have the allele t.
= During fertilisation the two alleles .T. from one parent say, through the pollen and .t. from the other parent then through the egg are united to produce zygote that have one .T. allele and one l. allele.
= In other words the hybrids have Tt.
= Since these hybrids contain alleles which express contrasting traits the plants are heterozygous.
= The production of gametes by the parents, the formation of zygotes, the `F_1 and F_2` plants can be understood from diagram called punnett square.