The Hindu: Published on 27 May 2025:
Why in News:
In April 2025, scientists published a landmark paper in Nature that finally identified the complete genetic basis of all seven traits studied by Gregor Mendel in his pea plant experiments over 160 years ago. This closes one of the oldest unresolved scientific questions in classical genetics.
Background-
In 1856–1864, Gregor Mendel, an Austrian monk, conducted breeding experiments on pea plants and discovered basic inheritance patterns.
He presented his results in 1865, and published in 1866 — which were largely ignored.
Mendel identified dominant and recessive traits, and quantified their inheritance patterns, like the 3:1 ratio in F2 generation.
In 1900, his work was rediscovered by Hugo de Vries, Carl Correns, and Erich von Tschermak, and became the foundation of modern genetics.
Despite being foundational, the exact genetic mechanisms behind all seven traits were not fully understood.
Key Scientific Discovery-
Scientists sequenced 697 pea plant variants, generating over 60 terabases of DNA using next-generation sequencing.
This led to:
Genetic mapping of all seven Mendelian traits.
Discovery of new alleles contributing to already known traits.
Resolution of the three remaining traits:
Pod Colour: Caused by a deletion near ChlG gene.
Pod Shape: Affected by MYB gene and CLE-peptide gene variants.
Flower Position: Linked to CIK-like-coreceptor kinase gene and a modifier locus.
The study also revealed 72 agriculturally important traits that could benefit crop development.
Key Issues Addressed-
Completeness of Mendel's laws: The study provides genetic proof for all seven traits Mendel observed.
Complexity beyond dominance: Traits are influenced by multiple alleles and modifiers — showing that inheritance is more complex than initially thought.
Population genetics: Found that pea plants have 8 genetic groups, despite only 4 known species — suggesting rich genetic diversity and hybridisation.
Implications-
For Science:
Completes a 160-year-old genetic puzzle.
Enhances understanding of gene expression, dominance, and interaction.
Validates classical genetics using modern genomics.
For Agriculture:
Opens avenues for improved crop breeding.
Potential for disease resistance, higher yield, and better adaptability.
Helps identify key traits for genetic modification or selective breeding.
For Education:
Strengthens teaching of Mendelian genetics by tying historical theory with molecular evidence.
Encourages appreciation of how long-standing questions can be answered through interdisciplinary research.
Conclusion:
This discovery is more than just a historical milestone. It bridges classical biology with modern genomics, fulfilling a scientific quest that began in a 19th-century monastery garden. Mendel’s simple questions about pea plants have now led to deep insights into the genome, and the legacy of his curiosity continues to shape the future of biology and agriculture.
