Mendelian inheritance or Mendelism corresponds to the passage of heredity characteristics from parents to their offspring. This is the base around which Mendelian genetics revolves. Gregor Mendel carried out experiments on Garden peas (Pisumsativum) through which he deduced two generalizations, which later came to be known as Mendel’s Laws of Heredity or the Mendelian Inheritance.
Mendel examined the genetics of pea plants to track down the inheritance of a variety of traits such as colour of the flower, position of the flower, colour of the seed, shape of the seed, which he achieved initially by pure-breeding parent plants with alterations of characteristics. For instance, the colour of the flower – white and violet. Briefly, pure-breeding translates to more offspring being produced when self-fertilization is performed over many generations.
Based on his research, Mendel proposed three laws which came to be known as Mendel’s law of inheritance, they are:
- The Law of Dominance
- The Law of Segregation
- The Law of Independent Assortment
Law Of Dominance
- Statement – “When parents with pure contrasting traits are crossed together, only one form of trait appears in the next generation. The hybrid offspring will exhibit only the dominant trait in the phenotype”
- Mendel observed that when an entity is heterozygous for a trait, the allele is the dominant one that is expressed.
Law of Segregation
The law of segregation states that – “During the formation of gametes, each gene separates from each other so that each gamete carries only one allele for each gene.”
This law is in accordance with the phenotypic ratio of 3:1. To explain further, the homozygous dominant and heterozygous offspring exhibit dominant traits, while the homozygous recessive exhibits the recessive trait
Law of Independent Assortment
- Statement – “The alleles of different genes are inherited independently within the organisms that reproduce sexually”
- To brief, the alleles of two more genes get sorted into gametes which are not dependent on each other. The allele that is acquired for one gene is not influenced by the allele received for some other gene
- This process of independent assortment is executed during the meiosis process wherein the chromosomes are halved, which is known as haploid. It takes place when the maternal and paternal genes randomly divide.
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