Traits are physical characteristics that can be displayed by animals (including human beings) and some plants. Inherited traits are passed down genetically from one generation to the next, while non-inherited traits are usually associated with a learned behavior. While there is a distinct difference between the two types of traits, ongoing research continues to determine how these traits are expressed and how they may be related to one another.
Inherited traits are characteristics acquired through the genetic information each parent contributes to the offspring. Inherited traits can be a physical trait or a behavior. Examples of physical inherited traits include hair, eye and skin color, facial features, height, dimples, length of toes and muscle structures. Examples of behavioral traits include a terrier's instinct to chase small animals or a cat puffing out its hair in response to a threat. Although inherited traits are often associated with things we can see, these traits also play an important role in how the body develops and functions. For example, inherited traits can increase risks for heart disease, high blood pressure, glaucoma and diabetes.
Non-inherited traits are learned traits, and in most cases these traits are learned from close or immediate family members like parents, grandparents and siblings. Examples of non-inherited traits include table manners, greeting customs (for example, handshake or bow), a preference for certain types of foods, and parenting skills. These types of traits can also be acquired through actions; for example, a weightlifter developing large muscles, a video game player enhancing fast hand and eye coordination or a yoga student gaining flexibility.
Expression of Traits
While inherited traits are genetically driven, they can also be influenced by non-inherited traits. In many instances, a trait that an individual expresses is due to both inherited and non-inherited causes. Here are a few examples of how these two traits can influence one another: Height is an inherited trait, but the total height that an individual achieves can be affected by nutrition; and muscle structure is an inherited trait, but muscle development which is expressed is related to diet and physical activities. Hair color is an inherited trait, but if someone grows up in a society where it is popular to dye hair, the expression of this trait may be changed.
Inherited and non-inherited traits are still extensively studied. All of our inherited traits, and how they are expressed, have not been discovered -- and a lot of genetic research is focused on identifying more of our inherited traits and how inherited and non-inherited traits work together to influence an expression. Genetic and behavior studies on twins have helped to contribute to our understanding of these traits, and these studies continue all over the world. For example, in the United Kingdom, the Department of Twin Research & Genetic Epidemiology performs studies on genetic and environmental traits through its registry of 12,000 adult twins.
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