Sex-linked Inheritance in Drosophila

Although the ratio of 3 to 1 in which contrasted characters reappear in the second or F2 generation is sometimes referred to as Mendel's Law of Heredity the really significant discovery of Mendel was not the 3 to 1 ratio but the segregation of the characters (or rather of the germinal representatives of the characters) which is the underlying cause of the appearance of the ratio.