Further Genetics

Further Genetics

Genetic Variations and Inheritance

Overview and Definition

  • All living organisms have their characteristics determined by genes inherited from their parents.
  • Genetic variation enables populations of organisms to adapt to their environment through the process of natural selection.
  • A gene mutation can result in a new genetic variation.

Gene Distribution

  • Genes are passed from parents to offspring in sex cells (sperm and eggs).
  • This is a process known as sexual reproduction.
  • Each offspring carries a combination of genes from both parents, which can create genetic variation.

Gene Mutation

  • Gene mutation refers to changes in the DNA sequence that makes up a gene.
  • Such changes can cause genetic variation and influence the characteristics of an organism.
  • Mutations can occur spontaneously or be induced by environmental influences like radiation.


  • Over time, genetic variations that boost an organism’s ability to survive and reproduce can lead to evolution within a population.
  • Evolution is a process that affects every variety of life form.

Genetic Disorders and Diseases

Overview and Definition

  • Genetic disorders are often caused by changes in DNA sequence that alter the function of genes.
  • They may be inherited from the parents or occur spontaneously in an individual.

Inherited Genetic Disorders

  • Conditions such as cystic fibrosis and sickle cell disease are caused by mutated genes inherited from parents.
  • Carriers of such genetic diseases may not show symptoms themselves, but can pass on the disease-causing genes to their offspring.

Genetic Engineering

Overview and Definition

  • Genetic engineering is the direct manipulation of an organism’s genes using biotechnology.
  • It involves the addition, removal, or alteration of genetic material in an organism’s DNA.

Applications of Genetic Engineering

  • Genetic engineering has diverse applications including the treatment of genetic disorders, creation of genetically modified organisms (GMOs), and improvement of crop species.
  • It has the potential to significantly impact human disease management, particularly through techniques like gene therapy.

Ethical Considerations

  • Apart from its utility, genetic engineering raises several ethical issues, such as concerns over ‘designer babies’ and the long-term effects of human genome editing.
  • Responsible utilization of genetic engineering constitutes a major contemporary scientific debate.