The scientific study of heredity is called genetics. It is a branch of biology that focuses on understanding the genetic makeup of organisms.
The history of genetics can be traced back to ancient civilizations, where people observed that certain traits were passed down from one generation to the next. However, it wasn’t until the 19th century that genetics began to emerge as a formal scientific field.
Gregor Mendel-Father of modern genetics:
Gregor Mendel was an Austrian monk and scientist recognized as the “Father of Modern Genetics” for his research on the hereditary inheritance of traits in pea plants. He was born in 1822 and spent most of his life studying biology and genetics.
In 1865, Mendel published a paper outlining his research on pea plants, in which he discovered that traits are inherited predictably. He proposed the laws of segregation and independent assortment, explaining how traits are passed down from generation to generation.
Mendel’s Laws:
Mendel’s law of genetic inheritance states that an individual’s inherited traits are determined by the genes inherited from their parents. Everyone carries two copies of each gene from their parents. The mix of these genes affects the characteristics of an individual.
Mendel’s Law of Segregation:
This law states that the two copies of each gene (alleles) are separated and passed on to the offspring during reproduction. This means that each child has a 50% chance of inheriting one of each of their parent’s alleles for each gene.
Mendel’s Law of Independent assortment:
The law states that the inheritance of one gene does not affect the inheritance of another gene. This means that the inheritance of a gene for eye color does not affect the inheritance of a gene for hair color.
Mendel’s law of dominance:
This law states that certain inherited traits are dominant, i.e., they are more likely to be expressed in an individual’s physical characteristics. These dominant traits will mask or suppress the expression of any recessive traits that an individual may possess.
Example:
Imagine that a couple has a child who has brown eyes. Both parents have brown eyes, but one parent also carries the gene for blue eyes. According to Mendel’s law of segregation, each parent will pass on one copy of their eye color gene to their child. If the child inherits the blue eye gene from one parent and the brown eye gene from the other, he will have brown eyes because brown is dominant over blue (Mendel’s law of dominance).
However, if the child inherits the blue eye gene from both parents, he will have blue eyes. In this case, Mendel’s law of independent assortment is also at play, as the inheritance of the blue eye gene does not affect the inheritance of any other traits.
Why Mendel selected pea plants for his research?
- Pea plants have a short generation time, which made it easier for Mendel to observe and record the inheritance of traits over multiple generations.
- They have a range of visible traits that are easy to observe, such as flower color, seed shape, and plant height, which allowed Mendel to see and record the inheritance patterns of different characteristics.
- Pea plants have a high degree of variation in their traits; this variation allowed Mendel to observe and study the inheritance of different traits and how they were passed down from one generation to the next.
Applications of Mendel’s Law:
Medicine — To understand the inheritance of genetic diseases and disorders, such as sickle cell anemia and cystic fibrosis. This helps doctors and genetic counsellors to predict the likelihood of a person developing a genetic disorder and to provide appropriate care and support.
Agriculture — Used in the development of genetically modified crops, which have improved yields and resistance to pests and diseases. They are also used for breeding animals with desired traits, such as disease resistance or higher milk production.
Forensics — To help identify suspects in criminal cases. DNA evidence is analysed to determine the likelihood that a suspect is related to a victim or witness.
Genetics counselling — To help families understand the likelihood of inheriting genetic disorders or traits and to provide support and guidance.
Mendel’s laws do not consider the interactions between genes and the environment, which can also affect the expression of traits.
Mendel’s laws apply only to organisms that reproduce sexually, such as animals and plants. They do not apply to organisms that reproduce asexually, such as bacteria.
Conclusion:
Mendel’s work was not widely known during his lifetime, but it laid the foundation for the modern understanding of genetics. His laws are still used to understand how traits are inherited and passed down from generation to generation.
Mendel died in 1884, but his work was rediscovered in the early 20th century, leading to a greater understanding of genetics and its role in biology. Today, Mendel is celebrated as a pioneer in genetics, and his contributions continue to be recognized and studied.
To learn about Mendel’s law through activity, please visit SimuLab.
Writer – Sneha Adsule
Subject Matter Expert (Biology)