Interaction of Heredity and Environment

All characteristics depend on genetic and environmental factors. Genetic and environmental interactions have their influence. In other words, how genes work depends on the environment in which they are located. Similarly, the environmental impact depends on the genes they act on.

For example, the height of people is different. Height is very genetic, but environmental variables can have a big influence. For example, Japanese Americans are higher and heavier on average than second-generation brothers who grew up in Japan, reflecting the influence of environmental variables, especially dietary habits.

Phenylketonuria (PKU) is an excellent example of environmental change in genetic control effect. PKU is a form of mental retardation caused by the toxic (injury) effect of abnormal degradation of essential amino acids phenylalanine found in all proteins. Since enzymes that degrade phenylalanine are defective, they accumulate and decompose abnormally. In other words, in PKU, a single gene may have a big influence on behavior. It is clearly a genetically affected process.

However, the effect of this defective gene expression depends on the environment in which it occurs. When this abnormal metabolism of phenylalanine is discovered, effective treatment is obtained: diet therapy of low phenylalanine. An abnormal gene still exists, but it is scarcely toxic due to a small amount of phenylalanine in the meal. This defective gene no longer appears as a mental retardation due to different environments. Phenylalanine significantly reduced the number of children with defective genes in food.

Treatment of PKU explains the principle that gene expression depends on its expression environment. This principle is called interaction between genetics and the environment This is an important idea. It says that all the features are dependent on the environment in which they are expressed, and even those greatly affected by heredity. Instead, all functions depend on the genotype they act on, even if they are greatly affected by environmental differences.

Another example of this idea is the environmental influence on rats genetically "labyrinth maze" and "labyrinth mat" (see exercise asgn1p). These lines selectively breed and learn the maze quickly or slowly. They will differ in maze learning only when they grew in "normal" laboratory settings. If they grow in a very limited environment, learning both types slowly learns. Both types of learning are the same if they grow in a rich, perceptual environment (Disney Land for Mice) (Cooper & Zubek. 1958)

A movie (Friedman, 1958) shows the effect of addiction and discipline on four puppies of dogs. Half of the two nests of four varieties (Ball, Beagle, Hound, Beagle) are "luxurious" twice a day, the other half subject to obedience training. Different treatments have little effect on foundation and hound dogs, but have a major impact on beagle dogs and huts. The difference between some of these varieties is the opposite. For example, adult addictive Beagle dogs are very cautious against humans, but trained Beagle dogs are functioning normally. By contrast, persistent huts work normally, but the disciplined people are very quiet and unresponsive. For a more complete summary of the video, please click here.

• Physical, cognitive, social, and emotional development are interrelated and subject to genetic and environmental interactions. For example, people with intellectual disabilities may develop at different rates depending on whether they raise early family intervention and educational services within the facility or at home. The relationship between human development and education is very close. To provide an appropriate level of instruction, the field of education sets goals based on the actual age of the student and the developmental stage of the student. Everyone is unique, but education groups students by age. But educational psychologists have studied and developed theories about development that help educators develop appropriate education.

The interaction of the genetic environment determines human characteristics and characteristics. Genetics determines the high level of development that a given environment can bring about over a given period. The environment determines the effectiveness of specific inheritance affecting development over time. The role of the environment is that it provides stimulus and causes reaction patterns prepared through maturity. It also provides a new pattern that leads people to learn to change old models.