Genetics || Introduction to Genetics 🧬 ||

Introduction to Genetics 🧬

DNA Strains

Genetics is a branch of biology concerned with the study of genes, genetic variation, and heredity in organisms.

In biology, a gene (from genos (Greek) meaning generation or birth or gender) is a basic unit of heredity and a sequence of nucleotides in DNA that encodes the synthesis of a gene product, either RNA or protein.

Heredity, also called inheritance or biological inheritance, is the passing on of traits from parents to their offspring; either through asexual reproduction or sexual reproduction, the offspring cells or organisms acquire the genetic information of their parents.

Pre and Post Mendelian Concepts of Heredity

Pre-Mendelian Concept of Heredity

1. Preformation Theory

2. Theory of Epigensis

3. Theory of acquired characters

4. Theory of Pangenes

Post-Mendelian Concept of Heredity

1. Incomplete dominance

2. Codominance

3. Multiple alleles

4. Linkage

5. Lethel genes

6. Polygenes

• In Brief above concept CLICK HERE 

Mendel’s Principles of Heredity

Gregor Johann Mendel is known as the father of genetics. He was the first to show the inheritance pattern of traits from one generation to the next generation. He did his research on the garden pea, Pisum sativum. He selected 7 pairs of contrasting traits like the red and yellow colour of the pod, round and wrinkled seeds, tall and short plants, etc. and crossbred the plants to understand their inheritance pattern.

 Mendel gave three fundamental laws of inheritance.

Law of dominance: States that in the heterozygous condition of the genotype for a pair of alleles, the alleles which express itself phenotypically is dominant and the one which can’t express is recessive.

Law of segregation: States that although the alleles of a character remain together for a long time, they do not mix with each other and separate at the time of gametogenesis so that each gamete receives only one allele of a trait, which is either dominant or recessive. When tall pea plants of the F1 generation (obtained by crossing homozygous tall and dwarf pea plants), are self-fertilised, we get tall and dwarf plants in the ratio of 3:1.

Law of Independent assortment: States that when more than a pair of characters are taken into consideration, alleles of a character can undergo any sort of combination to give rise to a phenotype differing from both the parents.

• Heredity Explained CLICK HERE