Questions and Answers
Who proposed the Germ Theory in 1883?
Weisman
What significant discovery did Gregor Mendel make in 1865?
Fundamental Laws of Heredity
Which year marks the publication of Mendel's investigations into inheritance?
1865/1866
Erwin Chargaff find that the amounts of adenine and thymine in DNA are not about the same.
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Who discovered the structure of the DNA molecule in 1953?
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What medical achievement became the first genetic disease to be treated using gene therapy in 1993?
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Which researchers analyzed mitochondrial DNA in different human races in 1987?
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Match the discoverer with their contribution:
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What did Edmund Beecher Wilson and Nettie Stevens propose in 1905?
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In what year was the Human Genome Project launched?
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When was the Human Genome Project successfully completed?
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Study Notes
History of Cytogenetics
- 1883: Van Beneden, Flemming, Strasburger, Boveri observed germ cells, supporting the continuity of germ plasm theory proposed by Weisman.
- 1883: Weisman proposed Germ Theory, stating hereditary factors transfer through sperm and egg, not somatic cells.
- 1879: O. Hertwig and H. Fol discovered fertilization in animals, enhancing understanding of reproduction.
- N/A: Strasburger discovered fertilization in plants, contributing to the theory that the cell nucleus bears hereditary information.
- N/A: Roux postulated chromatin, the substance of chromosomes, must have a linear organization.
- N/A: Weissman stated hereditary units are orderly disposed along chromosomes; laid groundwork for the study of heredity.
- 1865: Gregor Mendel discovered Fundamental Laws of Heredity through pea plant investigations, despite the lack of understanding of cytologic changes in sex cells.
- 1900: Theodor Boveri suggested chromosomes play a crucial role in inheritance.
- 1900: Walter Sutton observed chromosomes in grasshopper cells, moving towards genetic understanding.
- 1900/1901: Mendel's work was rediscovered by scientists Hugo De Vries, Erich von Tschermack, and Carl Correns.
- 1902: Archibald Garrod identified that some diseases are inherited.
- 1903: Sutton and Boveri suggested each egg or sperm cell carries one of each chromosome pair.
- 1905: Edmund Wilson and Nettie Stevens independently proposed that specific chromosomes determine sex: Y for males, and two Xs for females.
- 1906: Bateson coined the term ‘genetics’ to describe the field.
- 1909: Wilhelm Johannsen introduced terms 'gene', 'genotype', and 'phenotype' for heredity, organism's makeup, and appearance, respectively.
- 1910: Thomas Hunt Morgan provided evidence that genes are located on chromosomes, with some traits linked specifically to sex chromosomes.
- 1911/1913: Alfred Henry Sturtevant mapped genes on fly sex chromosomes, advancing genetic mapping techniques.
- 1912: Sir William Henry Bragg and his son discovered X-rays could be used to explore molecular structures of crystals.
- 1926: Morgan published the ‘Theory of the Gene’, defining genes' role in heredity.
- 1928: Frederick Griffith discovered 'transformation' in bacteria, hinting at genetic material's properties.
- 1944: Oswald Avery, Colin MacLeod, and Maclyn McCarty demonstrated that DNA serves as hereditary material using transformation experiments.
- 1949: Erwin Chargaff established that adenine and thymine ratios are approximately equal in DNA, alongside guanine and cytosine.
- 1953: James Watson and Francis Crick proposed the double-stranded helical structure of DNA, transforming genetic understanding.
- 1963-1966: Marshall Nirenberg and Heinrich Matthaei decoded the genetic code, clarifying how genetic information translates into proteins.
- 1977: Frederick Sanger, Walter Gilbert, and Allan Maxam independently sequenced DNA from viruses, marking milestones in genetic research.
- 1983: Kary Mullis discovered the Polymerase Chain Reaction (PCR), enabling amplification of DNA sequences for various studies.
- 1987: Rebecca Cann, Mark Stoneking, and Allan Wilson analyzed mitochondrial DNA, concluding that modern humans share a common ancestor from about 200,000 years ago.
- 1989: Francis Collins and Lap-chee Tsui sequenced the first human gene associated with cystic fibrosis.
- 1990: The Human Genome Project was initiated to map and understand all human genes.
- 1993: Cystic fibrosis became the first genetic disorder treated using gene therapy, representing a significant advancement in medicine.
- 1995: The genome of Haemophilus influenzae was sequenced, marking the first complete genome identification of an organism.
- 2000: Draft sequences of the human genome were released concurrently by the Human Genome Project and Celera Genomics.
- 2003: The Human Genome Project was successfully completed on April 14, representing a monumental achievement in genetics.
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Description
Test your knowledge on the history of cytogenetics and its key discoverers. This quiz covers significant observations and discoveries that have shaped the field. Ideal for students in Medical Technology or Medical Laboratory Science.
