4. Principles of Inheritance and Variation
The principles of inheritance and variation are explored through Mendel's groundbreaking work on pea plants, establishing foundational laws such as the Law of Dominance and the Law of Segregation. The chapter delves into genetic mechanisms including monohybrid and dihybrid crosses, incomplete dominance, and co-dominance, while also discussing the chromosomal theory of inheritance. It further addresses the complexities of genetic disorders and sex determination.
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4.3.1Law Of Independent Assortment
The Law of Independent Assortment states that the segregation of one pair of...
What we have learnt
- Inheritance is the process by which traits are passed from parents to offspring, while variation refers to differences among individuals.
- Mendel's experiments laid the groundwork for the laws of inheritance, using concepts like dominant and recessive traits to explain how genes behave.
- Genetic disorders can arise from mutations and can be analyzed through pedigree studies to understand inheritance patterns.
Key Concepts
- -- Dominance
- The phenomenon where one allele masks the effect of another allele for the same gene, typically seen in heterozygotes.
- -- Recessive
- An allele that is masked by a dominant allele and is expressed only in homozygous conditions.
- -- Monohybrid Cross
- A genetic cross between individuals that differ in one trait; used to observe the inheritance of a single character.
- -- Test Cross
- A genetic cross between a homozygous recessive individual and an individual with dominant phenotype to determine the genotype of the latter.
- -- Polygenic Inheritance
- A form of inheritance where multiple genes influence a single trait, resulting in continuous variation.
- -- Chromosomal Theory of Inheritance
- A theory proposing that genes are located on chromosomes and that the behavior of chromosomes during meiosis explains inheritance patterns.
- -- Pleiotropy
- The phenomenon where a single gene influences multiple phenotypic traits.
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