Topic 1 - History of Cytogenetics PDF

University of the Immaculate Conception Fr. Selga Street, Davao City College of Medical and Biological Sciences Medical Technology/Medical...

University of the Immaculate Conception Fr. Selga Street, Davao City College of Medical and Biological Sciences Medical Technology/Medical Laboratory Science TOPIC 1 – HISTORY OF CYTOGENETICS YEAR DISCOVERER/S DISCOVERY/ OBSERVATION Van Beneden, Flemming, Observed germ cells supporting the theory of the continuity of the germ 1883 Strasburger, Boveri, and plasm proposed by Weisman. others Proposed GERM THEORY: Transference of hereditary factors occurs 1883 Weisman through the continuity of germ plasm (sperm and egg), not somatic cells. O. Hertwig (foreseen), H. Fol 1879 Discovery of fertilization in animals. (observed) Discovery of fertilization in plants; contributed to the theory that the cell N/A Strasburger nucleus is the bearer of the physical basis of heredity. Postulated that chromatin, the substance of the nucleus constituting the N/A Roux chromosome, must have a linear organization. Stated that hereditary units are disposed along the chromosomes in an N/A Weissman orderly manner. Discovered the Fundamental Laws of Heredity; however, cytologic 1865 Gregor Mendel changes in sex cells were not well known to interpret the segregation of hereditary characters. YEAR DISCOVERER/S WITH DISCOVERY AND OBSERVATION 1865/ 1866 Gregor Mendel published his investigations into inheritance of pea plants 1890 Theodor Boveri suggested that chromosomes are involved with inheritance 1900 Walter Sutton observed chromosomes in grasshopper cells Mendel's work was rediscovered by three scientists: Hugo De Vries, Erich von Tschermack, and Carl 1900/1901 Correns 1902 Archibald Garrod discovered that some diseases must be inherited Sutton and Boveri, working independently, suggested that each egg of sperm cell contains only one 1903 of each chromosome pair Edmund Beecher Wilson and Nettie Stevens, working independently, proposed that certain 1905 chromosomes determine sex. They show that a single Y chromosome determines maleness, and two copies of the X chromosome determine femaleness 1906 Bateson gave the term ‘genetics’ Wilhelm Johannsen used the term 'gene' to describe the carrier of heredity, 'genotype' to describe 1909 an organism's genetic make-up, and 'phenotype' to describe an organism's outward appearance Thomas Hunt Morgan proved that genes are carried on chromosomes. He also showed that some 1910 characteristics are carried on the sex chromosome 1911/1913 Alfred Henry Sturtevant mapped the genes of the fruit fly’s sex chromosome Sir William Henry Bragg and his son discover that X-rays can be used to study the molecular 1912 structure of simple crystals, such as salt 1926 Morgan published the ‘Theory of the Gene’ 1928 Frederick Griffith discovered 'transformation' in bacteria Oswald Avery, Colin MacLeod, and Maclyn Mccatty used bacteria to show that DNA is the hereditary 1944 material 1949 Erwin Chargaff finds that the amounts of adenine and thymine in DNA are about the same, as area the amounts of guanine and cytosine 1953 James Watson and Francis Crick proposed that the DNA molecule is a double-stranded helix 1963-1966 Marshall Nirenberg and Heinrich Matthaei work out the genetic code DNA from virus is sequenced for the first time by Frederick Sanger, Walter Gilbert and Allan Maxam, 1977 working independently Kary Mullis discovered the Polymerase Chain Reaction (PCR), enabling lengths of DNA to be 1983 multiplied Rebecca Cann, Mark Stoneking, and Allan Wilson analyze mitochondrial DNA in different human races. 1987 They declared that humans have a common ancestor who lived 200,000 years ago The first Human gene is sequences by Francis Collins and Lap-chee Tsui. It is the gene that cause 1989 cystic fibrosis 1990 The Human Genome Project is launched 1993 Cystic fibrosis became the first genetic disease to be treated using gene therapy 1995 The genome of H.influenzae is sequenced. This is the first complete genome of an organism First draft sequences of human genome are released at the same time by the Human Genome Project 2000 and Celera genomics 2003 The Human Genome Project is successfully completed on 14th of April