Inheritance of One Gene Notes (original) (raw)

Last Updated : 2 May, 2023

We never wonder why Lion can give birth to Lions only, or why a bird can reproduce in the same species and no other species. Not everything is possible, Isn't it? Also, No human being look exactly identical, even with twins there are differences in every individual. Some siblings look similar while at the same time, some look really different.

Have you ever thought about who causes all these differences? All these questions are answered in the branch of science named Genetics. In this article, we will know more about the Inheritance of one gene.

Introduction to Inheritance and Variation

Inheritance is understanding how fundamental trait is passed down from generation to generation. Variation refers to the differences that exist between individuals of the same species. It's the raw material of evolution. Both Inheritance and Variation are the basic concepts of genetics and evolution.

_Inheritance of one gene_means that we get some of our traits (like the color of our eyes or hair) from our parents. We have different versions of a gene that controls these traits, and we get one version from our mom and one from our dad. Sometimes one version of the gene is stronger and it makes our trait look a certain way. But sometimes, both versions are kind of equal, and our trait ends up looking like a mix of both.

So when you look more like your mom or dad, it's because you inherited some of their genes!

The Story Behind Mendel’s Laws of Inheritance

Mendel's laws of inheritance are a set of fundamental principles that describe how traits are passed down from one generation to the next. The story begins in the mid-19th century when Gregor Mendel, Father of genetics, a monk living in a monastery in Brno (now in the Czech Republic), conducted a series of experiments with pea plants.

Mendel was curious about how traits are passed from one generation to another. But why only pea plants for the experiment? Because they were easily available, easy to grow, and had easily observable traits, such as seed color, flower color, and pod shape. His involved crossing pea plants with different traits and observing the traits of their offspring. He then analyzed the results of these crosses and derived a set of fundamental principles that described how traits were inherited and published his findings in 1866 in a paper called "Experiments in Plant Hybridization," but his work was largely ignored at the time. The three laws of inheritance are:

  1. Law of Segregation: This law states that each individual organism possesses two copies (alleles) of each gene, one inherited from each parent, meaning that each parent gives one copy of their traits to their child.
  2. Law of independent assortment: This law states that genes for different traits are passed down separately from each other.
  3. Law of dominance: This law states that one gene is more dominant than the other.

Overall, these rules help us understand how we inherit traits from our parents, and why we look similar or different from them.

Inheritance of One Gene

We can understand this concept through one of Mendel's experiments, where he crossed tall and dwarf pea plants to study the inheritance of one gene.

Based on these observations, he proposed that both genes are passed down to generations in the form of alleles. He called these things as ‘factors’, Now we call them genes. When two parents are not similar, one of the gene traits is dominant while the other is recessive in a child.

His observation on monohybrid crosses led to Principals or laws of Inheritance, we will discuss two in this article.

Law of Segregation

This law is based on the fact that the gene does not show any blending on itself and both the characters of a parent are present. In some cases, one can be dominant or a mix of the characters. As in Mendel's experiment, 1st generation showed all tall peas but the 2nd generation had both dwarf and tall peas.

Concept of Dominance: Every gene contains some kind of information in itself. Information about the character of a parent or a particular trait. The concept of dominance in genetics refers to how certain versions of a gene, called alleles, can have a stronger effect on a trait than others.

Law of Dominance:

It states the effects on the Characters that are controlled by discrete units called factors and In a dissimilar pair of factors one member of the pair dominates (dominant) the other (recessive).

Conclusion

In this article, we saw who started the study of genetics first and how it led to the principle of inheritance. Now can you answer why you are different from your siblings?