What is Mendels Law of Inheritance experiment and how was it conducted
The field of science that examines how genes and genetic traits are inherited from one generation to the other is known as genetics. Mendelian genetics is the study of the physical traits of individuals. These are also known as phenotypes.
Gregor Mendel was a 19th-century Augustinian monk and the humble founder of genetics. From 1856 up till 1863, Gregor Mendel tested 28,000 pea plants. From his observations, he deduced two theories. These are now called Mendel's Laws of Inheritance or Mendelian Inheritance. Mendel described these two laws in a paper called "Experiments on Plant Hybridization", published in 1866.
Read on to learn more about the Gregor Johann Mendel experiment.
Mendel’s Laws of Inheritance
Mendel crossed a true-breeding white flower and a purple flower plant. To his astonishment, he discovered that the product was a purple flower instead of a combination of two colours. He then deduced the idea of "factors" or hereditary units. Of these, one was recessive and the other dominant. Moreover, Mendel stated that these factors, which we now call genes, always occur in pairs.
Mendel then self-fertilised the F1 generation, and in the F2 generation, he observed that the flowers showed phenotypes in the ratio 3:1. Thus, he theorised that genes or these factors could be paired in three combinations: AA, Aa and aa. The capital A stands for the dominant trait while the lowercase a stands for the recessive trait.
Rack Your Brains: Before we move ahead, refresh your concepts by doing a simple task. Search Google or ask your friend for more exciting stuff on Mendel experiment class 10. Then write what you learn in your notebook.
The Gregor Johann Mendel Experiment
Gregor Mendel now decided to analyse the patterns of inheritance in the pea plant. He picked out the pea plant due to the following reasons:
Peas are self-pollinating. They can also be self-pollinated.
Peas are annual plants. Thus, many generations of this plant can be examined in a very short span of time.
Pea plants have a set of 7 distinct character traits.
Peas are easy to grow.
After that, Mendel began to observe a pair of contrasting traits at a time, and he experimented using true-breeding pea plants. These were the characteristics that he studied.
How well have you learnt about Mendel’s experiments? Test yourself with this quiz.
Pop Quiz 1
Which of these is a trait Mendel studied in the pea plant?
Leaf shape
Leaf colour
Flower shape
Seed shape
Mendel made sure to use only true-breeding plants in his experiments. True-breeding plants exhibit stable inheritance of traits. Subsequently, in each of his experiments, Mendel noticed a pattern of traits and inheritance. These laid the foundation of his laws of inheritance.
Read on to find out more about the results of the Mendel experiment (class 10).
Results of Gregor Mendel’s Experiments
The following were the observed results of his experiments with the pea plant.
Firstly, Mendel took note that all plants in the F1 generation were tall and there were no dwarf plants.
Secondly, in the F2 generation, Mendel made the observation that pea plants were tall, while one was a dwarf plant.
Consequently, Mendel observed that the same results were seen for other characters as well.
In the F1 generation, these traits of only one parent came to the fore. Meanwhile, in the F2 generation, these traits of the other parent plant also came to the fore.
The traits that appeared in F1 are now known as dominant traits, whereas the ones that appeared in the F2 generation are known as recessive traits.
To sum it up, the genes which were passed from one generation to the others were existing in pairs called alleles. Two similar alleles are known as homozygous alleles. Different alleles are called heterozygous alleles.
Test what you know with the following quiz.
Pop Quiz 2
A heterozygous yellow pea plant has the following alleles.
YY
Yy
yy
Finally, Mendel's observations led to the three primary Laws of Inheritance.
Law of Dominance
The Law of Segregation
Law of Independent Assortment.
For more on Mendel experiment class 10 and the laws of inheritance, check out our detailed study material. Now you can also download our Vedantu app for easier access to our detailed notes, as well as online interactive sessions for doubt clearing.
FAQs on Mendels Law of Inheritance Experiment in Pea Plants
1. What is Mendel’s Law of Inheritance?
Mendel’s Law of Inheritance refers to the basic principles of heredity proposed by Gregor Mendel that explain how traits are passed from parents to offspring. These laws include:
- Law of Dominance – One allele can mask the expression of another.
- Law of Segregation – Allele pairs separate during gamete formation.
- Law of Independent Assortment – Different gene pairs assort independently during inheritance.
2. What experiment did Gregor Mendel perform to discover the laws of inheritance?
Gregor Mendel discovered the laws of inheritance by performing controlled cross-pollination experiments on pea plants (Pisum sativum). His experiment involved:
- Selecting plants with contrasting traits (e.g., tall vs dwarf).
- Cross-pollinating pure-breeding varieties.
- Observing traits in F1 and F2 generations.
- Recording numerical ratios of inherited traits.
3. Why did Mendel choose pea plants for his inheritance experiments?
Mendel chose pea plants because they had clear, contrasting traits and were easy to control experimentally. Pea plants were ideal because:
- They show distinct traits like yellow vs green seeds.
- They have a short life cycle.
- They produce many offspring.
- They allow easy self-pollination and cross-pollination.
4. What is the Law of Dominance in Mendel’s experiment?
The Law of Dominance states that when two different alleles are present, only the dominant allele expresses itself in the phenotype. In Mendel’s monohybrid cross:
- Tall plant (TT) × Dwarf plant (tt)
- All F1 offspring were Tall (Tt).
5. What is the Law of Segregation?
The Law of Segregation states that allele pairs separate during the formation of gametes, so each gamete carries only one allele for a trait. During meiosis:
- Each parent has two alleles for a trait.
- The alleles separate into different gametes.
- Offspring receive one allele from each parent.
6. What is the Law of Independent Assortment?
The Law of Independent Assortment states that genes for different traits are inherited independently of each other if they are on different chromosomes. In a dihybrid cross (e.g., seed color and seed shape):
- Each pair of alleles segregates independently.
- The F2 generation shows a 9:3:3:1 phenotypic ratio.
7. What is a monohybrid cross in Mendel’s experiment?
A monohybrid cross is a genetic cross that studies the inheritance of a single trait. In Mendel’s monohybrid experiment:
- He crossed Tall (TT) and Dwarf (tt) plants.
- The F1 generation showed only Tall plants (Tt).
- The F2 generation showed a 3:1 ratio of Tall to Dwarf.
8. What is a dihybrid cross in Mendel’s experiment?
A dihybrid cross is a genetic cross that studies the inheritance of two traits simultaneously. In Mendel’s dihybrid experiment:
- He crossed plants differing in seed shape and seed color.
- The F1 generation showed dominant traits.
- The F2 generation showed a 9:3:3:1 phenotypic ratio.
9. What were the F1 and F2 generations in Mendel’s experiment?
The F1 generation is the first filial generation produced from a parental cross, and the F2 generation is produced by self-pollinating F1 individuals. In Mendel’s experiment:
- P generation: Pure-breeding parents (TT × tt).
- F1 generation: All heterozygous (Tt), showing dominant traits.
- F2 generation: Shows a 3:1 phenotypic ratio.
10. What is the significance of Mendel’s Law of Inheritance in biology?
Mendel’s Law of Inheritance is significant because it forms the foundation of modern genetics and explains how traits are transmitted across generations. Its importance includes:
- Understanding hereditary diseases.
- Plant and animal breeding programs.
- Studying genetic variation and evolution.
- Forming the basis for molecular genetics research.
