The intellectual troika that helped understand heredity
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The intellectual troika that helped understand heredity
Subject: Science and Technology
Section: Biotechnology
- Mendel propounded that information on “traits” gets passed on from one generation to another as particulate ‘elements’ and traits in the present generation can be traced back to past generations.
- Galton and his supporters — notably Karl Pearson and W.F.R. Weldon — criticised Mendel because his ‘laws’ ignored ancestors; the genetic compositions of only the parents but not of other ancestors, matter in the determination of the characteristics of a person.
- Galtonian ‘law’ stated that other ancestors also matter.
- Pearson claimed that observed correlations of characteristics between various types of relatives were higher than those expected under Mendel’s laws.
Mendel’s Law of inheritance
The three laws of inheritance proposed by Mendel include:
- Law of Dominance
- This is also called Mendel’s first law of inheritance. According to the law of dominance, hybrid offspring will only inherit the dominant trait in the phenotype. The alleles that are suppressed are called the recessive traits while the alleles that determine the trait are known as the dominant traits
- Law of Segregation
- The law of segregation states that during the production of gametes, two copies of each hereditary factor segregate so that offspring acquire one factor from each parent. In other words, allele (alternative form of the gene) pairs segregate during the formation of gamete and re-unite randomly during fertilization. This is also known as Mendel’s third law of inheritance.
- Law of Independent Assortment
- Also known as Mendel’s second law of inheritance, the law of independent assortment states that a pair of traits segregates independently of another pair during gamete formation. As the individual heredity factors assort independently, different traits get equal opportunity to occur together.