Hi! I'm Gregor Mendel and this is how I discovered the fundamental laws of inheritance.
Mendel discovered that the pink flower trait is dominant and that the white flower trait is recessive.
If the phenotype of the flower is always pink when when the genotypes of a pure-bred red and white pea plant are used, then how is a white pea plant flower made?
Gregor Mendel was interested in how pea plants can come in two varieties of the same gene called alleles that cause the flowers to either be red or white.
The dominant trait occurs if one or more dominant alleles are present making it Homozygous dominant/Heterozygous. The recessive trait is observed only if there are two recessive alleles are present meaning that it is Homozygous recessive.
This can be explained through a Punnet square.
Mendel planted one pure-bread pink flower and one pure-bread white. Because each of the flowers have to pass one one of their genotype, each offspring will have one P. This means that they will all have the dominant trait making them pink. This means that the offspring are heterozygous.
Mendel then planted two of the offspring flowers which then created three pink flowers and one white. One of the pink and the white flower is homozygous as there are two recessive alleles in them and the other two pink flowers are heterozygous.