in genetics, the intensification or attenuation of a genetic character in offspring as compared with the parent individuals. Transgression occurs when the quantitative manifestation of a character is associated with the functioning of two or more genes. When each parent individual has one or more dominant genes, two or more dominant genes may combine in the offspring, resulting in the intensification of the given character (positive transgression). An analogous combination of recessive genes leads to an attenuated manifestation of characters (negative transgression).
Knowledge of transgression is applied in selective breeding to obtain new varieties, notably in self-fertilizing species of plants. Applications of transgression are limited since its occurrence decreases with an increase in the number of genes causing the quantitative manifestation of a character.
the advance of the sea onto the land. In most cases, transgression occurs as a result of a subsidence of the land; less often, it is due to a rise in the level of the ocean. A transgression consists of a series of relatively brief advances and retreats of the sea, with the advances predominating. The sequence of deposits formed during a transgression generally shows a transition from shallow-water facies at the bottom to deeper-water facies at the top. The opposite of a transgression is called a regression.