Genetics Essentials 2e

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Transcript Genetics Essentials 2e

Benjamin A. Pierce
•Genetics Essentials
• Concepts and Connections
© 2013 W. H. Freeman and Company
Benjamin A. Pierce
•Genetics Essentials
• Concepts and Connections
Introduction to Genetics
© 2013 W. H. Freeman and Company
The Case of the Hopi Native Americans
Albinism: 1:200 in the tribe
1:20000 elsewhere
The Case of the Hopi Native Americans
What are the reasons for
such high frequency?
Take a guess or two……
Genetics: the Study of Heredity
• Most rapidly developing field of science.
• affects every living organism
• affects all aspects of human society
• affects each individual
• “Young science” even it was used for thousands of years
• Agriculture
• Understanding genetics is applying it:
• Pharmaceutical
• Medicine
• Diseases
• Gene therapy
Genetics: as to you the Bio Student?
• Understanding is critical for Bio students:
• One of the unifying principles of biology
• To understand evolution
• To understand development
• To apply it to all fields of biological study
• Taxonomy
• Ecology
• Behavior
• Any others you might think of??
Genetic Diversity and Evolution
• Enormous diversity of organisms
• complexity
• organization
• environment
• What is common?
• Use similar genetic systems
• DNA and RNA
• Almost identical coding
• Copy and translate is remarkably similar
• All lead to common ancestor….
‘….life is river of DNA that runs through time, connecting
all organisms past and present….’ (R. Dawkins,
So what?
• How knowing the genetic mechanisms of one organism
• Bacteria- yeast – flies- humans
• And anywhere in-between
• Evolution is based on genetic change
• Step one: Random changes arise in heredity
• Step two: Number of organisms with the change
increases or decreases
• Use genetic techniques to establish evolutionary
• Neanderthals and us
• The origins of Homo Sapiens
• How modern protein looked 2.5 billion years ago
• And how it will look in the future
Divisions of Genetics
• Three major subdivisions
• Transmission genetics
• Molecular genetics
• Population genetics
• Transmission Genetics
• Basic principles of heredity
• Chromosomes and genes (arrangement, mapping)
• Molecular Genetics
• Chemical nature of genes
• Encoding, replication and expression of information.
• Population Genetics
• Genetic composition of individuals of same species
• Change over time and space - evolution
Model Genetic Organisms
• Organisms with characteristics useful for genetic analysis
• Short generation time
• Large but manageable number of progeny
• Laboratory adaptability
• Inexpensive housing and propagation
Some Other Models
• Depending on the area of study other model organisms are
• Neurospora crassa (bread mold)
• Zea mays (corn)
• Xenopus laevis (clawed frog)
• Danio rerio (zebra fish)
Some Genetics History
• Domestication of plants and animals is the first evidence of
understanding of heredity and its application:
• Wheat, lentils, barley, dogs, sheep, goats (10-12000 years
• Sophisticated techniques (artificial pollination; 4000 years
• Many other plants and animals throughout time
Some Genetics History
• The Greeks:
• Pangenesis
• Inheritance of acquired characteristics
• Seventeenth century:
• Preformationism
• Blending inheritance
Genetics History: the Science at Last
• The prerequisites:
• Plant reproduction experiments (17-18th century)
• Gregor Mendel (19th century)
• Cell theory
• Look closely at the cells, mitosis observed
• Theory of evolution
• Charles Darwin’s ‘On the Origin of Species’
• Germ-plasm theory
Genetics History: the Science at Last
• Rediscovery of Mendel leads to explosion of genetic
• 1902: genes are located on chromosomes
• 1910: first genetic mutation in flies
• 1930s: transformation of bacteria
• 1940s: DNA emerges as ‘suspect’ carrying hereditary
• 1953: 3-D DNA structure
• 1960s: genetic code established
• 1970s: recombinant DNA and DNA sequencing
• 1983: PCR
• 1990s: Human Genome Project; first complete genome
sequences of bacteria and yeast
• 2000: rough draft of the human genome published; 2003
The Future of Genetics
• Very bright:
• Rapid sequencing methods (personalized medicine)
• More diseases linked to specific genetic makeup
• Evolutionary linkages
• Functions of RNAs (siRNA; microRNA)
• Bioinformatics
• Crop improvement
• Too many to list……
Important Fundamental Concepts
• Home assignment pp. 11-12 (will be tested)
READ CHAPTER 2, will be tested
• Home assignment pp. 17-38 (will be tested)
• Processes and concepts that are known from BIO-150