Mendel’s Work with Laws of Inheritance

Syllabus: GS3/Science and Technology

Context

• A global team mapped pea genomic diversity, advancing breeding research, revisiting Mendel’s traits, and boosting sustainable agriculture.

About

• The research, which appears in the journal Nature, is built on a collaboration between the John Innes Centre (JIC) and the Chinese Academy of Agricultural Sciences (CAAS), together with other research groups in China, the UK, USA, and France.
• The research has connected more than 70 agronomic traits to corresponding genomic locations. 
  • The many different genetic markers at each of these locations can be used to accelerate pea improvement.
• Their work has uncovered new insights into the traits that Mendel famously studied and revealed valuable genetic diversity.

Significance of the Study

• The expanded gene bank and genomic resources now available to researchers and breeders worldwide have the potential to transform pea breeding and advance research into this environmentally vital legume.
• The study comes at a time when peas and other legumes are being called upon as a source of plant protein, and as sustainable crops which can fix their own nitrogen. 
• It will pave the way for more predictive breeding – such as using AI models which can select combinations of genes to deliver better yielding, disease resistant, agronomically viable pea plants.

Mendel’s Experiments

• Mendel is known as the father of genetics because of his ground-breaking work on inheritance in pea plants 150 years ago.
• He focused on seven traits: pea seed shape (round or wrinkled), pea seed colour (green or yellow), pod shape (constricted or inflated), pod colour (green or yellow), flower colour (purple or white), plant size (tall or dwarf) and position of flowers (axial or terminal).
• Mendel chose pea plants because they have easily observable traits (e.g., flower color, seed shape), grow quickly, and can be self- or cross-pollinated.

• Over many years of experiments, involving thousands of plants, he established fundamental rules of inheritance, how characteristics are passed down through the generations, and single-handedly laid the groundwork for the science of genetics.

Mendel’s Laws of Inheritance

• Law of Segregation: Each individual has two alleles for a trait, but only one allele is passed on to the offspring during gamete formation.
  • Traits are determined by pairs of alleles.
  • During meiosis, the two alleles segregate (separate), so each gamete receives only one allele.
• Law of Independent Assortment: Genes for different traits assort independently of one another during gamete formation.
  • The inheritance of one trait (e.g., plant height) does not affect the inheritance of another trait (e.g., seed color), assuming the genes are on different chromosomes.
  • This explains the variety in traits among offspring.
• Law of Dominance: When two different alleles are present in a pair, one (the dominant allele) masks the expression of the other (the recessive allele).
  • In a heterozygous condition (e.g., Tt), the dominant trait (tallness) is expressed, and the recessive trait (shortness) is hidden.

Conclusion

• Mendel’s work remained unnoticed until it was rediscovered in 1900. 
• Today, his principles are the basis for classical genetics, helping us understand how traits are passed from one generation to another.

Source: TH