Monohybrid cross

[1][2] The character(s) being studied in a monohybrid cross are governed by two or multiple variations for a single location of a gene.

Then carry out such a cross, each parent is chosen to be homozygous or true breeding for a given trait (locus).

Probability theory predicts that three quarters of the F2 generation will have the dominant allele's phenotype.

Gregor Mendel (1822–1884) was an Austrian monk who theorized basic rules of inheritance.

The garden pea was chosen as an experimental organism because many varieties were available that bred true for qualitative traits and their pollination could be manipulated.

By removing the stamens from unripe flowers, Mendel could brush pollen from another variety on the carpels when they ripened.

But two thirds of the round seeds in the F2 were heterozygous and their self-pollination produced both phenotypes in the ratio of a typical F1 cross.

As the size of the sample gets larger, however, chance deviations become minimized and the ratios approach the theoretical predictions more closely.

While his individual plants deviated widely from the expected 3:1 ratio, the group as a whole approached it quite closely.

To explain his results, Mendel formulated a hypothesis that included the following: In the organism, there is a pair of factors that controls the appearance of a given characteristic.

If an organism has two unlike factors (called alleles) for a characteristic, one may be expressed to the total exclusion of the other (dominant vs recessive).

In order to test his hypothesis, Mendel predicted the outcome of a breeding experiment that he had not carried out yet.