Introduction to Genetics - Practice Questions & MCQ

• Heredity is a process of transmission of traits from parents to their offspring.
• Such transmissible characters are called heritable characters. 
• It involves the transfer of genes from parents to offsprings through asexual or sexual reproduction.
• The subject that deals with the inheritance, as well as the variation of characters from parents to offspring, is Genetics.
• Inheritance is the process by which characters are passed on from parent to progeny; it is the basis of heredity.
• Variation is the degree by which progeny differ from their parents.
• Variations can be heritable or non-heritable.
• Variations are more pronounced in sexual reproduction.
• Mutations provide discontinuous variations while sexual reproduction provides continuous variations.

Ancient Theories of Heredity:

• Pythagoras (500 BC) proposed that every organ of the human body gives out some types of vapours. These vapours contribute to the formation of a human being.
• Hippocrates (400 BC) proposed that reproductive material is handed over from all parts of the body to the developing individual.
• Aristotle (300 BC) proposed that semen has some vitalizing effect. Semen was considered to be a pure form of blood and that it puts life into the inert matter provided by mother.
• Leonardo Da Vinci (1452-1519) proposed that mother and father contribute equally to the heredity of the offspring.
• Some scientists speculated that there is a ‘little man’ or Homunculus in the sperm.
• The theory of Homunculus was published in the journal des Scavans on 7th Feb 1695.
• K.F. Wolff (1738-1794) refuted the Homunculus theory. He proposed that gametes contain substances that are capable of organizing the body after fertilization. 
• This theory formed the basis of the Theory of Epigenesis.
• Theory of Epigenesis proposed that many new organs and tissues were absent originally and have developed gradually.
• Weismann in 1892 proposed the Theory of Germplasm to explain the heredity.
• According to this theory, the body of an organism contains two types of cells namely somatic cells and reproductive cells. 
• The germ cells contain the germplasm which plays an important role in the development of the human being.