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Chromosomes and Inheritance
Walter Sutton published “On the Morphology of the Chromosome Group in Brachystola magna”, hypothesizing that chromosomes carry the inheritance and that they occur in distinct pairs within a cell’s nucleus. Sutton also argued that how chromosomes act when sex cells divide was the basis for the Mendelian Law of Heredity. -
Embryo Cells Carry Genetic Information
German embryologist Hans Spemann slip a 2-celled salamander embryo and each cell grew to adulthood, providing proof that early embryo cells carry necessary genetic information. This finally disproved Weismann’s 1885 theory that the amount of genetic information in cells decreases with each division. -
Nuclear Transfer Experiments Results Published
Hans Spemann published the results of his 1928 primitive nuclear transfer experiments involving salamander embryos in the book “Embryonic Development and Induction.” Spemann argued the next step for research should be the cloning organisms by extracting the nucleus of a differentiated cell and putting it into an enucleated egg. -
Genetic Information in DNA
Oswald Avery found that a cell’s genetic information was carried in DNA. -
First Animal Cloning
First animal cloning: Robert Briggs and Thomas J. King cloned northern leopard frogs. -
Structure of DNA Discovered
Francis Crick and James Watson, working at Cambridge’s Cavendish Labratory, discovered the structure of DNA. -
Term "Clone" Coined
Biologist J.B.S. Haldane coined the term “clone” in a speech entitled “Biological Possibilities for the Human Species of the Next Ten-Thousand Years.” -
Genetic Code Discovered
Marshall Nirenberg, Heinrich Matthaei, and Severo Ochoa broke the genetic code, discovering what codon sequences specified each of the twenty amino acids. -
DNA Ligase Isolated
DNA ligase, the enzyme responsible for binding strands of DNA, was isolated. -
First Gene Isolated
James Shapiero and Johnathan Beckwith announced that they had isolated the first gene. -
First Recombinant DNA Molecule
Paul Berg combined the DNA of two different organisms, thus creating the first recombinant DNA molecules. -
First Recombinant DNA Organism
Stanley Cohen and Herbert Boyer created the first recombinant DNA organism using recombinant DNA techniques pioneered by Paul Berg. Also known as gene splicing, this technique that allows scientists to manipulate the DNA of an organism - the basis of genetic engineering. -
Asexual Mice Reproduction
Karl Illmensee and Peter Hoppe created mice with only a single parent. -
Vitro Fertilization
Baby Louise, the first child conceived through in vitro fertilization, was born -
3 Mice Cloned
Karl Illmensee claimed to have cloned three mice. -
Diamond v. Chakrabarty
In the case Diamond v. Chakrabarty, the United States Supreme Court ruled that “live, human made microorganism is patentable material.” -
Polymerase Chain Reaction
Kary B. Mullis developed the polymerase chain reaction (PCR). This process allows for the rapid synthesis of designated fragments of DNA. -
First Human Mother-to-Mother Embryo Transfer
The first human mother-to-mother embryo transfer was completed. -
Cloned Sheep from Embryo Cells
Steen Willadsen cloned a sheep from embryo cells, the first verified example of mammal cloning using the process of nuclear transfer. -
Duplication of Prize Catlle Embryos
Steen Willadsen used his cloning technique to duplicate prize cattle embryos. -
First Transgenic Livestock
Ralph Brinster created the first transgenic livestock: pigs that produce human growth hormone. -
Human Genome Project
The National Institutes of Health officially launched the Human Genome Project to locate the 50,000 to 100,000 genes and sequence the estimated 3 billion nucleotides of the human genome. -
First Human Embryos Cloned
Human embryos were first cloned. -
Cloned First Organism from Adult Cells
Dolly, the first organism every to be cloned from adult cells, was born. -
Lamb Cloned from Skin Cells
Ian Wilmut and Keith Campbell, the scientists who created Dolly, also created Polly, a Poll Dorset lamb cloned from skin cells grown in a lab and genetically altered to contain a human gene. -
Banning of Cloning Proposed
President Clinton proposed legislation to ban the cloning of humans for at least 5 years. -
Ban on Human Cloning
Nineteen European nations signed a ban on human cloning.