Genetics
மரபியல்
Do not confuse inheritance with mere resemblance. Genetics is the study of the transmission of hereditary characters and the variations that arise during this process.
The idea
Genetics is a branch of biology that deals with the inheritance and variation of characters from parents to offspring. It provides a scientific framework to understand why offspring resemble or differ from their parents.
Why it matters
It exists to explain the biological mechanisms of heredity and the diversity observed within species, ensuring the continuity of life while allowing for evolutionary change.
NEET lens
Genetics is the scientific framework explaining why offspring differ from parents. NCERT defines it strictly as the study of inheritance and variation. Expect questions focusing on the distinction between these two fundamental concepts.
Introduction
Genetics is the branch of biology that deals with inheritance and variation of characters from parents to offspring.
Core concept
History: humans used variation in plants and animals for selective breeding long before genetics existed (e.g. Sahiwal cows in Punjab). Gregor Mendel (1856-1863) did hybridisation experiments on garden peas for seven years and proposed the laws of inheritance. His work was rediscovered in 1900 by de Vries, Correns and von Tschermak. Sutton and Boveri proposed the chromosomal theory of inheritance (genes are on chromosomes). T.H. Morgan worked on Drosophila and discovered linkage and recombination; his student Sturtevant used recombination frequency to map genes.
Go deeper
Mendel succeeded because he used true-breeding lines, studied one or two characters at a time, used large sample sizes and applied statistics to his results — a first in biology.
From Class 10
In Class 10 you met Mendel's pea experiments and dominant and recessive traits. Class 12 genetics builds on that with ratios, crosses and exceptions.