Principles of Inheritance & Variation
Class 12th Biology
Chapter: Principles of Inheritance & Variation
Topic: Principles of Inheritance & Variation
Principles of Inheritance & Variation
Class 12th Biology
Chapter: Principles of Inheritance & Variation
Topic: Inheritance of One Gene
Principles of Inheritance & Variation
Class 12th Biology
Chapter: Principles of Inheritance & Variation
Topic: Mendel’s Law of Inheritance
Principles of Inheritance & Variation
Class 12th Biology
Chapter: Principles of Inheritance & Variation
Topic: Incomplete Dominance
Principles of Inheritance & Variation
Class 12th Biology
Chapter: Principles of Inheritance & Variation
Topic: Co-Dominance
Principles of Inheritance & Variation
Class 12th Biology
Chapter: Principles of Inheritance & Variation
Topic: Inheritance of Two Gene
Principles of Inheritance & Variation
Class 12th Biology
Chapter: Principles of Inheritance & Variation
Topic: Chromosomal Theory of Inheritance
Principles of Inheritance & Variation
Class 12th Biology
Chapter: Principles of Inheritance & Variation
Topic: Sex Determination
Principles of Inheritance & Variation
Class 12th Biology
Chapter: Principles of Inheritance & Variation
Topic: Mutation and Genetic Disorders
Principles of Inheritance & Variation
Class 12th Biology
Chapter: Principles of Inheritance & Variation
Topic: Mendelian Disorders
Principles of Inheritance & Variation
Class 12th Biology
Chapter: Principles of Inheritance & Variation
Topic: Chromosomal Disorders
Principles of Inheritance and Variation The principles of inheritance and variation describe how genetic traits are passed down from one generation to the next and how they can vary within a population. These principles were first described by Gregor Mendel, who conducted experiments on pea plants in the mid-19th century.
The law of segregation states that each individual has two alleles for each gene, which are separated during the formation of gametes (sex cells) so that each gamete carries only one allele. The law of independent assortment states that the inheritance of one gene does not affect the inheritance of another gene. Genetic variation within a population is caused by mutations, which are changes in the DNA sequence that can result in different forms of a gene, called alleles. Alleles can be dominant or recessive, depending on their effect on the phenotype (observable traits) of an organism. In a heterozygous individual (one with two different alleles), the dominant allele will be expressed, while the recessive allele will only be expressed in a homozygous individual (one with two identical recessive alleles).