Inheritance
பாரம்பரியம்
Do not confuse 'Inheritance' with 'Variation'. Inheritance is the mechanism of transmission; Variation is the degree of difference. If you fail to distinguish these, you lose marks on the very first page of the chapter.
The idea
Inheritance is the process by which characters are passed on from parent to progeny. It serves as the fundamental basis of heredity.
Why it matters
It exists to ensure the transmission of genetic information and species-specific traits across generations.
NEET lens
Inheritance is the process by which characters are passed from parent to progeny. It is the fundamental basis of heredity. NEET examiners test your understanding of this definition as the foundation for Mendelian genetics. Master this concept to avoid errors in pedigree analysis questions.
Introduction
Inheritance is the process by which characters are passed on from parent to progeny. It is the basis of heredity — the reason offspring resemble their parents.
Core concept
Key terms: a gene (Mendel's 'factor') is the unit of inheritance; alleles are slightly different forms of the same gene that code for a pair of contrasting traits (e.g. T and t). Genotype = the genetic make-up (TT, Tt, tt); phenotype = the observable character (tall, dwarf). Mendel's laws describe how genes pass on: Law of Dominance, Law of Segregation and Law of Independent Assortment. Patterns beyond Mendel include incomplete dominance (snapdragon flower colour), co-dominance (ABO blood groups), multiple alleles (ABO), pleiotropy (phenylketonuria) and polygenic inheritance (human skin colour).
Go deeper
Some traits are controlled by a single gene; others involve interacting genes or many genes. Fruit colour in summer squash is a classic older NEET example of gene interaction (dominant epistasis), where one gene masks the expression of another — this goes beyond the current NCERT text.
From Class 10
In Class 10 you learnt that traits like eye colour are passed from parents to children through genes on chromosomes.