From Mendel to Modern

The History of Genetic Science

• Paul Berg pioneered the process of making Recombinant DNA by fusing different DNA from different organisms together.
• Greek scholars Pythagoras, Plato, and Aristotle had different theories on inheritance but agreed that there must be a way for information to be passed from one generation to another.
• Gregor Mendel's Laws of Inheritance included the Law of Independent Assortment and the Law of Independent Segregation which explained how inherited characteristics exist in alternative forms.
• Each individual possesses two paired alleles, one inherited from each parent, which segregate in germ cells and recombine during reproduction.
• Johann Friedrich Miescher was the first to isolate DNA using leukocytes in pus and later salmon sperm.
• Albrecht Kossel discovered that nuclein consisted of a protein component called histones and a non-protein component called nucleic acids containing four nitrogen-containing groups.
• Walter Flemming studied stained salamander embryos going through cell division and observed the separation process of mitosis where identical sets of chromosomes are pulled apart and separately go to the two dividing cells.
• William Bateson coined the term genetics to describe the study of inheritance.
• Wilhelm Johannsen introduced the basic terminology of genetics: genes, genotype, and phenotype.
• The carrier of genetic information/unit of inheritance needs to duplicate and evenly divide.
• Mendel's factors that carried the traits were called genes.
• Ernest Haeckel proposed that the nucleus contained the factors responsible for the transmission of hereditary information.