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Genetics
- study of genes and how these are passed from one generation to the next
- branch of biology concerned with the study of DNA of organisms; how DNA manifest at genes and how this are inherited by offsprings
Phenotype
physical traits that is manifested
Genotype
actual genes
1905: William Bateson
coined the term "genetics"
1906
Genetics was first used in the International Conference on Genetics.
Charles Darwin
discovered several species of finches on his voyage to Galapagos Islands which helped him to develop his theory of natural selection and evolution.
concluded that there are forces in nature that affects the survival of organisms
Mid to Late 19th Century
beginning of genetics
July 1858
Charles Darwin and Alfred Russell Wallace jointly presented their knowledge and paper at the Linnean Society of London.
Alfred Russel Wallace
Ventured the Malay archipelago and had the same results with Darwin's voyage
1850s
Gregor Mendel began his experiment with peas.
1865
Gregor Mendel presented his Principle of Inheritance.
1866
Gregor Mendel published his paper
Gregor Mendel
- Proposed two main principles of inheritance: Law of Segregation and the Law of Independent Assortment.
- An Austrian monk who was driven by curiosity, conducted an experiment of cross breeding of peas (Pisum sativum) in his garden.
- Debunked Blending Theory with experiment and instead coined discrete units or genes
1858: Scientific Milieu
- new era for genetics; drifting from natural philosophy to a more empirical and experimental era
- the scientific community was involved in many discoveries and developments
- they were easy to grow, had many visible traits, and could be controlled for pollination (self-pollinating)
- with clear-cut differences (e.g. round vs. wrinkled)
- True-breeding plants
Reasons on Choosing Peas
Particulate inheritance
- is a principle or pattern of inheritance proposed by Gregor Mendel that did not originate from Blending Theory.
- traits are passed down through generations via genes.
Blending Theory
Thinking of biologist before Mendel's work in which offsprings are blended from parents.
1866: Ernst Haeckel
discovered the cell nucleus and proposed that the nucleus is the primary structure involved in inheritance—called nucleus "idioplasm"
1869: Friedrich Miescher
- primary person behind the discovered nuclein, the substance that is now known as DNA, in pus cells.
- separated nuclein into protein and acid components, as he sees the nuclein is rich in phosphorus and named it nucleic acid
- His discovery opened the study of molecular basis of genetics with the bearing that the nuclein is the genetic material related to inheritance
Early 20th Century
people discovered DNA are packed into chromosomes that actually holds the genetic or hereditary material that are passed to the offsprings
Hugo de Vries
credited with discovering mutations and coining the term
1900s: Hugo de Vries, Carl Correns and Erich von Tschermak
rediscovered Mendelian Inheritance, confirmed its principles and discrete units (DNA)
1908: Hardy-Weinberg principle
- proposed independently by G.H. Hardy and Wilhelm Weinberg, genetic equilibrium principle with a goal to understand how genetic variation is maintained or changed in a population.
- States that in an ideal population, the alleles and genotype frequencies will not change and are used throughout generations.
1903: Chromosomal Theory of Inheritance
independently proposed by Walter Sutton and Theodor Boveri, states that chromosomes carry the hereditary material in that their behavior during meiosis parallels Mendelian's Segregation and Independent Assortment based on observation on crossing over.
1910: Thomas Hunt Morgan
- experiment on Drosophila (fruit flies) that confirmed the Mendelian theory of inheritance
- discovered the term "linked genes" or genes that are located on the same chromosome and tend to be inherited together (cannot be separated); and coined the term "linkage" to describe the physical association of genes on a chromosome.
1944: Oswald Avery, Collin MacLeod and Maclyn McCarty
proved and defined that DNA is the "transforming principle"
1928: Frederick Griffith
- conducted an transformation experiment using Streptococcus
pneumoniae to prove that DNA is the actual hereditary or genetic material that encodes for a specific trait.
- used S strains (virulent and has protective polysaccharide capsule) and R strains (non-virulent, without capsule).
- observed that a living non-virulent bacterial strain could be transformed into a virulent strain after it was mixed with a dead virulent strain
- the first to reveal the "transforming principle," which led to the discovery that DNA acts as the carrier of genetic information.
1953: James Watson and Francis Crick
- proposed the double helix structure of DNA
- won the Nobel Prize in Physiology or Medicine in
1962.
1952: Alfred Hershey and Martha Chase
provided a very conclusive evidence that only DNA contains the hereditary material using an experiment with bacteriophages
Rosalind Franklin
- X-ray crystallographer who primarily uncovered the structure of DNA using X-ray diffraction.
- The diameter of the DNA double helix is 2 nm, with 10 base pairs present per turn of the helix or periodicity.
Maurice Wilkins
co-worker of Rosalind that spilled the information to Watson and Crick
Legal Aspect
Forensic Science (bodily fluids are examined and used in determining the perpetrator)
Parentage (maternity/paternity test)
Selective Breeding
Agriculture (Genetic engineering is used to modify the crops' gene to withstand weather, weathering, etc.)
Medicine/Clinical Genetics
Genetic Screening (To know if the offspring has a genetic inheritable diseases)
Gene therapy (Alter genes to inactivate gene that codes for disease)
Wildlife Conservation
Germplasm (Gametes are used to conserve germplasm)
Genetics as a basis for Biological Sciences
Evolutionary Biology
Systematics
Taxonomy
Genetics is a foundation for Biological Sciences
Note 
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