What is Polygenic Inheritance Explain with an Example
Polygenic inheritance is a phenomenon in genetics where a trait is influenced by multiple genes, each contributing a small effect. Unlike Mendelian inheritance, which involves the inheritance of a single gene, polygenic inheritance is responsible for many complex traits in humans, such as height, skin color, and intelligence. In this article, we will explore the concept of polygenic inheritance and illustrate it with an example.
Polygenic inheritance is the result of the combined effects of multiple genes, each with different alleles. These genes interact with each other and with environmental factors to produce the observed trait. The genes involved in polygenic inheritance are often located on different chromosomes, which makes it challenging to identify and study them individually.
To understand polygenic inheritance, let’s consider the example of human height. Height is a complex trait influenced by more than 700 genes. Each gene contributes a small amount to the overall height, and the combined effect of these genes determines an individual’s height. While it is impossible to identify a single gene responsible for height, researchers have identified several genes that contribute to this trait.
One of the genes associated with height is the LMX1B gene, which is involved in the development of the skeleton. Another gene, the FGF8 gene, plays a role in the growth of bones and cartilage. These genes, along with many others, contribute to the overall height of an individual.
In polygenic inheritance, the expression of a trait can be represented by a bell-shaped curve, also known as a normal distribution. This curve shows that most individuals will fall within a certain range of heights, with fewer individuals being exceptionally tall or short. The curve is determined by the combined effects of the genes and environmental factors.
It is important to note that polygenic inheritance does not imply that the genes involved are less significant. Instead, it suggests that the effect of each gene is small and that the trait is influenced by multiple factors. This makes polygenic inheritance a complex and fascinating area of study in genetics.
In conclusion, polygenic inheritance is a phenomenon where a trait is influenced by multiple genes, each contributing a small effect. The example of human height illustrates how polygenic inheritance can lead to the complex and diverse traits observed in humans. As researchers continue to study polygenic inheritance, we can expect to gain a better understanding of the complex interplay between genes and environmental factors in shaping our traits.
