What Is Heredity?
Heredity can be defined as the phenomenon wherein traits appear to be transmitted from one generation to the next. The science of genetics has demonstrated that heredity results from the transmission of genes from parents to offspring. A single gene may carry the instructions for a single trait, but more frequently genes interact to produce a specific trait or characteristic. For example, it is now known that eye color in humans is a polygenic trait (multiple genes carry the instructions, or code for, eye color). Expression of genes (e.g., the product of the instructions) is often influenced by the environment. For example, genes most certainly influence height and weight, but nutrition also plays a significant role in the determination of these characteristics. Offspring, therefore tend to resemble parents or other close relatives rather than unrelated individuals who do not share as many of the same kinds of genes.