Genetics test
1
Introduction to Genetics
© 2015 Pearson Education, Inc.
Chapter
Lecture Presentation by Dr. Cindy Malone, California State University Northridge
Chapter 1 Learning Objectives
1.1 Know the basics of Genetics’ history
1.2 Be familiar with the transition from Mendel to DNA in less than a century
1.3 Review the double helix and its facilitation of the era of molecular genetics
1.4 Understand the use of recombinant DNA technology and its relationship to the era of cloning
1.5 Examples of the impact of Biotechnology
1.6 Define and know examples of work in Genomics, Proteomics, and Bioinformatics fields
1.7 Understand how and why genetic studies rely on the use of model organisms
1.8 Awareness of rapid change in the field of Genetics
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Section 1.1: History of Genetics
1600–1850: The Dawn of Modern Biology
William Harvey: Theory of epigenesis
Structures such as body organs
are not initially present in the early embryo
are formed later
Schleiden and Schwann: The cell theory (1830)
All organisms are composed of basic structural units called cells
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Section 1.1: The Origin of Species
1859: Darwin published his ideas on the theory of evolution in The Origin of Species
Descent with modification
Existing species arose from other ancestral species
Natural selection
The mechanism for evolutionary change
Theory of evolution
Independently proposed by Alfred Russel Wallace
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Section 1.2: Variation of Inheritance
1866: Mendel publishes his findings
Mendel worked with peas and used quantitative data to support his ideas
Traits are passed from generation to generation
Transmission of genetic information from parents to offspring
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Section 1.2: Mitosis and Meiosis
Mitosis
Chromosomes are copied and distributed
The two resulting daughter cells each receive a diploid set
Meiosis
Chromosomes are copied and distributed
Resulting cells (gametes) receive only half the number of chromosomes
Are haploid
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Section 1.2: Diploid number (2n)
Most eukaryotes have a characteristic number of chromosomes
Called diploid number (2n)
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Section 1.2: Chromosomal Theory of Inheritance
Inherited traits are controlled by genes residing on chromosomes
Genes are transmitted through gametes
Maintains genetic continuity from generation to generation
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Section 1.2: Alleles – The Source of Genetic Variation
Alleles
Mutations produce alleles of a gene
The source of genetic variation
Genotype
The set of alleles for a given trait
Phenotype
Expression of the genotype
Produces an observable trait or phenotype
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Section 1.2: DNA Is the Carrier of Genetic Information
DNA is the carrier of genetic information
Not protein
Research of Avery, MacLeod, and McCarty
In 1944, published experiments showing DNA was carrier of genetic information in bacteria
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© 2015 Pearson Education, Inc.
Figure 1-7
Section 1.3: Structure of DNA
DNA is
antiparallel
double-stranded helix
made of nucleotides
Monomer is
nucleotide consisting of a sugar (deoxyribose)
bonded to a phosphate
also bonded to the bases adenine, cytosine, guanine, and thymine
Nucleotides form A–T and G–C
complementary base pairing across the helix
Figure 1-7
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Section 1.3: Structure of RNA
RNA is similar to DNA, except that
it is usually single-stranded
it has uracil (U) in place of thymine (T)
the sugar in RNA nucleotides is ribose instead of deoxyribose
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Section 1.3: The Central Dogma
DNA RNA Protein
DNA is transcribed to RNA
RNA is translated into protein (Figure 1-8)
This is known as the central dogma of genetics
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Diagram of the Central Dogma
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Section 1.3: Proteins
Proteins are the end product of gene expression
Protein action or location in a cell produces phenotype(s)
Diversity of proteins
20 different amino acids
Numerous combinations of these 20
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Section 1.4: Restriction Enzymes
1970s: researchers discovered that restriction enzymes in bacteria cut viral DNA at specific sites
Restriction enzymes allowed the advent of recombinant DNA and cloning
© 2015 Pearson Education, Inc.
© 2015 Pearson Education, Inc.
Figure 1-11
Section 1.5: Biotechnology
Biotechnology is now used in
health care
supermarket products
agriculture
court system
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Section 1.5: Biotechnology Used in Agriculture
Biotechnology has been used for the genetic modification of crop plants for
increased herbicide, insect, and viral resistance
nutritional enhancement
water use reduction
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Section 1.5: Biotechnology in Genetics and Medicine
Biotechnology-derived genetic testing
Utilized in prenatal diagnosis
Tests for heritable disorders
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Figure 1-12
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1.6 Genomics, Proteomics, and Bioinformatics Are New and Expanding Fields
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Section 1.6: Genomics, Proteomics, and Bioinformatics
Genomics
Studies the structure, function, and evolution of genes and genomes
Proteomics
Identifies a set of proteins present in cells under a given set of conditions
Studies their functions and interactions
Bioinformatics
Uses hardware and software for processing nucleotide and protein data
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Section 1.6: Common Origin
All life has a common origin
Genes with similar functions in different organisms are similar in structure and in DNA sequence
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Section 1.6: Modern Approaches to Understanding Gene Function
Reverse genetics
DNA sequence of a particular gene of interest (GOI) is known, but its function is not
Gene knockout
Allows scientists to render genes nonfunctional to investigate the possible role of that gene
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Section 1.7: Model Organisms Used to Study Human Diseases
Model organisms for genetic study meet these criteria:
Easy to grow
Short life cycle
Produce many offspring
Genetic analysis is straightforward
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© 2015 Pearson Education, Inc.
Table 1.1
Section 1.7: Models of Human Diseases
Recombinant DNA technology
The ability to transfer genes across species
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Section 1.7: Model Organism: Historical and Modern
First generation of model organisms:
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Figure 1-13
30
Section 1.7: Model Organism: Historical and Modern
Modern model organisms:
Viruses: T phages and lambda phages
Bacteria: Escherichia coli
Yeast: Saccharomyces cerevisiae
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Section 1.8: The Age of Genetics
1865: Mendel set the stage for the study of genetics
Genetics rapidly developed from Mendel’s peas to the Human Genome Project
1962: Nobel Prize awarded to Watson, Crick, and Wilkins
Numerous Nobel Prizes have been awarded since then in the field of genetics
© 2015 Pearson Education, Inc.
© 2015 Pearson Education, Inc.
Figure 1.13
Section 1.8: Future of Genetics
Society is faced with a host of sensitive genetics-related issues:
Prenatal testing
Ownership of genes
Access to/safety of gene therapy
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