Due to the phenomenon of dominance a recessive allele remains obscure in the hybrid. But when two different genes which are not alleles, both affect the same character in such a way that the expression of one masks, inhibits or suppresses the expression of the other gene, it is called epistasis. The gene that suppresses [...]
In 1900 Bateson and his colleagues studied inheritance of comb shape in fowls. There are four types of combs in fowls: rose, pea, walnut and single. Bateson first performed a cross between rose and single. The Fx hens all had a rose comb, and on inbreeding gave rise to an F2 progeny of rose and [...]
A monohybrid cross between a red-flowered snapdragon (Antirrhinum majus) and a white flowered variety does not produce red or white flowered plants in Fl as expected from mendelism. Instead the flowers are pink, i.e. intermediate between the two parents. This is because neither red flower colour nor white is dominant, but each allele has its [...]
Mendel extended his observations to trihybrid crosses involving three pairs of contrasting characters. The characters he considered were: seed shape—smooth (S) vs. wrinkled (s); colour of cotyledons—yellow (Y) vs. green (y); and flower colour—violet (V) vs. white (u). The F1 hybrid produces 8 types of gametes. These on selfing have equal chances to combine with [...]
Mendel made crosses between pea plants differing in two characters such as texture of seed and colour of cotyledons. Such a cross in which inheritance of two characters is considered is called a dihybrid cross. First of all Mendel crossed a pea plant that was breeding true for round seeds with a plant that bred [...]
