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BIO 106
LECTURE 1
CONTENTS
A. Definition of Genetics B. History of Genetics C. Scope of Genetics D. Application of Genetics
the study of HEREDITY and VARIATION
1858: Theory of Natural Selection
Charles Darwin Alfred Russell Wallace
1859
Charles Darwin
1866
Publication of results on inheritance of factors in garden peas
Gregor Mendel
1900: independent discovery and verification of Mendel’s principles
Carl Correns
Hugo de Vries
Erich von Tschermak
1902: noticed relationships of Mendel’s factors with chromosome behavior
Walter S. Sutton
WS Sutton and Theodor Boveri (studying sea urchins) independently propose the
chromosome theory of heredity
1901 Hugo de Vries adopts the term mutation
coined the terms genetics, allele, homozygous, heterozygous
1905: explained how gender is determined by special chromosomes;
William Bateson
: Proposed that some human diseases are due to "inborn errors of metabolism" that result from the lack of a specific enzyme.
Archibald Garrod
independently formulated the Hardy-Weinberg principle
of population genetics
Godfrey Hardy & Wilhelm Weinberg
1908
discovery of how genes are transmitted by chromosomes; sex linkage in Drosophila
1910
1927: X-rays caused artificial gene mutations in Drosophila
Herman J. Muller
1928: Proposed that some unknown "principle" had transformed the harmless R strain of Diplococcus to the virulent S strain.
Frederick Griffith
1931: cytological proof for crossing-over in maize
with Harriet B. Creighton
1941: Irradiated the red bread mold, Neurospora, and proved that the gene produces its effect by regulating particular enzymes; - proposed 1 gene-1 enzyme concept
Reported that they had purified the
transforming principle in Griffith's
experiment and that it was DNA.
Carl Correns
1944 Oswald Avery Colin MacLeod Maclyn McCarty
Developed the hypothesis of transposable elements to explain color variations in corn.
Late 1940s - 1950
1950: Discovered a one-to-one ratio of A to T and G to C in DNA samples from a variety of organisms.
Erwin Chargaff
1951: show by X-ray crystallography that DNA exists as two strands wound together in a spiral or helical shape
Rosalind Franklin Maurice H.F. Wilkins
1952: Used phages in which the protein was labeled with 35S and the DNA with 32P for the final proof that DNA is the molecule of heredity.
Martha Chase Alfred Hershey
1953: Solved the three-dimensional structure of the DNA molecule.
Francis Crick James Watson
1956: showed that the diploid chromosome number for humans is 46
Joe Hin Tijo Albert Levan
1958: Used isotopes of nitrogen to prove the semiconservative replication of DNA.
Matthew Meselson & Frank Stahl
1958: Purified DNA polymerase I from E. coli, the first enzyme that made DNA in a test tube.
Arthur Kornberg
his work in DNA synthesis led to creating recombinant DNA and genetic engineering.
1966: Led teams that cracked the genetic code- that triplet mRNA codons specify each of the twenty amino acids.
H. Gobind Khorana Marshall Nirenberg
1972
Stanley Cohen Herb Boyer
Paul Berg
1973: Led the team at Cold Spring Harbor Laboratory that refined DNA electrophoresis by using agarose gel and staining with ethidium bromide.
Joseph Sambrook
1973: Showed that a recombinant DNA molecule can be maintained and replicated in E. coli.
Stanley Cohen (with Annie Chang)
Developed the chain termination (dideoxy) method for sequencing DNA.
Fred Sanger
1977
The first genetic engineering company (Genentech) is founded, using recombinant DNA methods to make medically important drugs.
1978: Somatostatin became the first human hormone produced using recombinant DNA technology; Walter Gilbert coins the terms INTRON and EXON
1981: Three independent research teams announced the discovery of human oncogenes (cancer genes).
1983: Used blood samples collected by Nancy Wexler and her co-workers to demonstrate that the Huntington's disease gene is on chromosome 4.
James Gusella
1985: Published a paper describing the
polymerase chain reaction (PCR), the
most sensitive assay for DNA yet
devised. Kary B. Mullis
1988: the Human Genome Project began with the goal of determining the entire sequence of DNA composing human chromosomes.
Alec Jeffreys
1989: Coined the term DNA fingerprinting and was the first to use DNA
polymorphisms in paternity, immigration, and murder cases;
-birth of 1st American test tube baby
Identified the gene coding for the cystic fibrosis transmembrane conductance regulator protein (CFTR) on chromosome 7 that, when mutant,
causes cystic fibrosis.
Francis Collins Lap-Chee Tsui
1989
1990: First gene replacement therapy-T cells of a four-year old girl were exposed outside of her body to retroviruses containing an RNA copy of a normal ADA gene. This allowed her immune system to begin functioning.
1993: FlavrSavr tomatoes, genetically engineered for longer shelf life, were marketed.
1997 : Complete Saccharomyces cerevisiae genome is sequenced; complete E. coli genome is sequenced
1998 Caenorhabditis elegans becomes the first animal whose genome is totally sequenced
1999 A human MHC (HLA-DR52) haplotype is totally sequenced (October). Human chromosome 22 becomes the first one to be sequenced completely (November)
2003 Complete sequence of human Y-chromosome was published
3 major fields of Genetics: 1. Transmission genetics 2. Molecular and biochemical
genetics 3. Population and biometrical
genetics
TRANSMISSION GENETICS/CLASSICAL GENETICS
Studies:
- Basic principles of genetics
- transmission of genetic material from one generation to the other
- Focus: individual organism
- emphasis:
Relationship between chromosomes and heredity
Arrangement of genes on the chromosomes
Gene mapping
MOLECULAR AND BIOCHEMICAL GENETICS
- study of the chemical nature (structure and function) of genes
- Emphasis:
How genetic information is encoded, replicated and processed.
The cellular processes of replication, transcription and translation
Gene regulation, the process that controls the expression of genetic information.
POPULATION AND BIOMETRICAL GENETICS - study of the behavior and effects of genes in population, often
using mathematical models
- Focus: the group of genes found in a population.
- emphasis: How the genetic composition of a group changes over time.
- Can include quantitative genetics (predict the response to selection given data on the phenotype and relationships of individuals) and ecological genetics (wild populations of organisms, and attempts to collect data on the ecological aspects of individuals as well as molecular markers from those individuals)
Other Fields:
1. Behavioral genetics
- studies the influence of varying genetics on animal behavior, the effects of human disorders as well as its causes; has yielded some very interesting questions about the evolution of various behaviors, and even some fundamental principles of evolution in general.
2. Clinical genetics
- diagnosis, treatment, and counseling of patients with genetic disorders or syndromes
AGRICULTURE
Selective breeding: cross-breeding of two
parents, each with some good traits, to produce
offspring with the good traits of both parents
BENEFITS OF Selective Breeding
better resistance to pests and diseases
improved nutritional value (superior quality)
fruits with longer shelf life
bigger animal, more meat, more milk production
Increase food production
Disadvantage:
removal of some genes from the gene pool
TRANSGENIC ORGANISMS:
Transgenic plants: resistant to pests, diseases
Transgenic animals: chickens with
HGH to make them grow large and
very fast
Transgenic bacteria: for mass production of insulin, HGH, blood clotting factor
MEDICINE Accurate diagnosis of diseases
Preventing use of medicine or disease prevention
Inherited drug sensitivities
Chromosomal abnormalities
Production of vaccines, antibodies, vitamins, insulin
Gene therapy
Future: personalized medicine
LEGAL (genetic fingerprinting)
Crimes (forensic science)
Parentage
INDUSTRIES - Provide some synthetically produced raw materials
for industries
Brewing industry
INDUSTRIES The pharmaceutical industry has developed strains of
molds, bacteria, and other microorganisms high in antibiotic yield. (examples: Penicillin and cyclosporin from fungi, streptomycin and ampicillin from bacteria)
HUMANS: possibility of making children with only the desirable
traits
Babies who have deficiency could be treated with additions being done to their genetic structure.
Those who cannot reproduce due to medical complications have also seen positive results with surrogate parent's concept becoming available.
Increasing life span (vaccination, medications, vitamins)
ENVIRONMENT
Oil spills
Polluted waterways
BIOREMEDIATION
ENVIRONMENT - Protection of
valuable wild populations (genetic monitoring using genetic markers) thus probably solving problems causing reduction of population
Distribution of elephant in Tanzania