Term
| The Future Isn’t What It Used to Be: Biotechnology |
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Definition
| The DNA of two people of the same sex is 99.9% identical |
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Term
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Definition
–Any use of living organisms to create products or facilitate processes
–Example—HGH (human growth hormone)
Secreted by pituitary
Necessary for childhood growth
Missing in some individuals
In the past, replaced by extraction of hormone from cadavers
Costly and unsafe
–Now, gene for HGH is isolated, inserted into E. coli, and expressed by the vats-full. |
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Term
Tools of Biotechnology
--Restriction Enzymes |
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Definition
–Cut DNA into pieces (designed to cut invading viral DNA)
–At highly specific sequences of bases called recognition sequence
–Example—BamHI cuts only at GGATCC
–“Sticky ends” can reseal, thus pasting two pieces together like DNA Velcro.
–1000 Identified! |
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Term
Tools of Biotechnology
--Plasmids |
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Definition
–Extra-chromosomal rings of bacterial DNA
–Replicate independently of bacterial chromosome
–Inherited by both daughter cells
–Bacteria take up plasmids from surroundings (transformation) |
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Term
Getting Human Genes into Plasmids
-Recombinant DNA |
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Definition
| Two or more segments of DNA that have been combined by humans into a sequence that does not exist in nature. |
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Term
| Cloning: Make an Exact Genetic Copy |
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Definition
–Sheep Dolly cloned in 1997 (Ian Wilmut at PPL Therapeutics)
Spark added to two cells
Udder and egg cells fused
Mimicked by the stimulation by sperm
Surrogate mother
Now has her own offspring
Aging problems
–DNA from 6 yr old
–Arthritis
Dead in 2003 |
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Term
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Definition
–Combine cloning with recombinant DNA technology.
–Creating livestock that contain human genes needed to treat genetic disorders like hemophilia B (Factor IX) in Polly.
Clone & Human gene!
Factor IX in milk!
–More useful chemical form than bacteria. |
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Term
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Definition
Creating livestock to serve as organ donors, or blood donors.
Pigs
Remove DNA coding for proteins that are recognized as foreign by human immune system
Then, clone and harvest organs |
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Term
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Definition
–U.S. Prof. & Italian doctor
–Realian sect in Canada already proposed to start
Cells from baby before dying
–Clones already exist—identical twins
Began as one cell
–Ethical considerations:
When is it OK—To replace child who died? To create mini-me? For infertile couples?
What about the number of attempts that may fail? |
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Term
| PCR—Polymerase Chain Reaction |
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Definition
–Use primers—short sections of DNA complementary to both ends of the DNA to be copied
–Primers signal DNA polymerase to copy |
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Term
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Definition
–“Amplifies” a specific piece of DNA from small samples
Crime scene investigation
–Medical—Lyme disease diagnosis
–Archeology—5,200-year-old Iceman compared to modern Europeans
More closely related to northern and central
–Invented in 1983 by Kary Mullis
Nobel prize in Chemistry |
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Term
| Visualizing DNA Sequences |
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Definition
–How do we compare DNA?
–Restriction enzymes cleave DNA into manageable pieces.
–Gel electrophoresis—DNA moves in an electric field through a gel matrix.
–Larger pieces are more easily retarded by holes in the gel, so they travel less than smaller pieces.
–Dyes are used to visualize DNA as bands |
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Term
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Definition
–Characterizing a stretch of DNA by the order of As, Gs, Cs, and Ts
–Regularly performed by machine |
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Term
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Definition
–Police are making DNA data banks
Cold Hits
–Free wrongly accused |
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Term
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Definition
–Locate and catalogue human genome.
1990—Publicly funded Human Genome Project
1998—Craig Venter (biotech company, Celera) sought sequence of entire genome by 2001.
Sequence published in February 2001.
Genes for sale
–Surprised that human genome contains only 26,000 to 40,000 total genes—not 100,000.
–Benefit—finding disease genes at increasing rate.
Library analogy
Give genes descriptive names
Only 1.5% of your DNA codes for proteins! |
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Term
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Definition
–code for more than one protein
–Exons are rearranged before translation |
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Term
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Definition
| the study of genome data; like mining to find gene functions |
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Term
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Definition
| the study of protein expression and function. |
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Term
| Genetics’ Next Phase: Genomics and Proteomics |
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Definition
–Unimaginable complexity must be solved using computer technology “bioinformatics.”
Bio & computers
30,000 genes
100’s of thousands of proteins |
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Term
| Alternative mRNA splicing |
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Definition
| –Splice exons together in alternative ways to make different proteins |
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Term
| Genetically Modified Foods: Protests |
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Definition
–1998—European Union restricts approval of new GM foods.
–2000—U.S. genetically modified corn approved only for animal feed ends up in taco shells |
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Term
| Genetically Modified Foods: Promise |
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Definition
–Golden Rice
Genes from bacterium and daffodil to make beta-carotene.
Enrich diets of 124 million children worldwide who are lacking Vitamin A.
–1/2 million blind each yr
–2 million die each yr.
–Bananas
Resistant to fungal infections
Produce edible vaccines (maybe |
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Term
Genetically Modified Foods: Concerns
–Allergic Reactions |
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Definition
No evidence of harm to humans.
Considered “low probability.”
American Medical Assoc. said no justification for special labeling, recommends continued research into safety |
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Term
Genetically Modified Foods: Concerns
–Environmental Contamination |
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Definition
Threat of hybridization with wild relatives, sharing genes and thus creating super weeds.
Study in England from 1990—in 12 locations, not one of various varieties of GM crops spread beyond the growth plots. |
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Term
| Genetically Modified Foods: They’re Here… |
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Definition
–In United States, 54% soybeans, 48% cotton, 25% of all corn are GM.
–Most contain Bt gene, with no harm.
Bacteria gene that produces a protein that kills bugs
–Reduced chemical insecticide use on cotton in the Southeast by 72%.
–Suggested use with buffer zone to prevent development of resistance. |
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Term
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Definition
| Human gene therapy is a recombinant DNA procedure that seeks to treat disease by altering the genes of the afflicted person |
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Term
| Microevolution Leads to Macroevolution |
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Definition
–Macroevolution
•grand scale
•new species
•major changes in family lines |
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Term
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Definition
•Darwin
•minor changes in the genetic composition of a population |
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Term
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Definition
•results from microevolution
•changes that increase likelihood of survival and reproduction
–Adaptation by natural selection is responsible for evolution
•accumulation of small changes leads to new species (macroevolution). |
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Term
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Definition
Rate
–Mammals evolve slowly
–Fish (Coelacanth) even slower.
Spurts? |
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Term
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Definition
| •macroevolution occurs at a constant, gradual pace |
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Term
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Definition
•Major environmental changes trigger bursts of rapid speciation, followed by periods of gradual change.
–“Radiation” after mass extinction
–Niles Eldredge & Stephen Jay Gould
•Fossil record supports both hypotheses |
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Term
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Definition
Evidence of macroevolution
Fossils
–The preserved remains, traces, or tracks of once-living creatures.
Dating Fossils
–Relative age of rock was determined by its position relative to other rocks.
–Today, measuring the rate of decay of certain radioisotopes w/in the rock.
•1/2 life
–Time for 1/2 to decay into new
History
–fossils lined up by age show successive evolutionary change.
–Strongest evidence
Gaps in the Fossil Record
–Very complete w/ few gaps
–Among vertebrates
•fossils link all major groups
•Ex. Archaeopteryx, lungfish |
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Term
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Definition
–served a function in an ancestor
–no function now
–evidence for evolution
•Ex. appendix
•Dew claw on dogs
•Dolphin and Whale hind legs |
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Term
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Definition
Evolution is linked to changes in DNA
–organisms more distantly related have more genetic changes in DNA.
–English in: US, Austrailia, England |
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Term
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Definition
–longer ago the diverged, the differences in the nucleotide sequence
•cytochrome c gene
–(codes for a protein that plays a key role in oxidative metabolism).
–Change occurs at a constant rate; thus a clock |
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Term
| Proteins Evolve at Different Rates |
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Definition
–Not all proteins evolve at the same rate.
–Cytochrome c and hemoglobin have changed at relatively constant rates, but other proteins, like the fibrinopeptides, evolve considerably faster |
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Term
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Definition
–relatedness of organisms
•Fossil
•Molecular evidence
•Both give similar results |
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Term
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Definition
–relatedness of organisms
•Fossil
•Molecular evidence
•Both give similar results |
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Term
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Definition
Development
–Many go through the same stages of embryologic development
–Evidence for evolution
–Debated during Darwin’s ti |
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Term
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Definition
–Homologous Structures
•similar structure
•Dif. function
•Divergent Evolution
–Vert forelimbs
•diverged to perform different functions
•consist of the same bone structure
•indicates common ancestry |
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Term
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Definition
• Same function
• Different lineage
•Convergent Evolution
–similar structures in animals
–same solution to a problem
–NO common ancestor.
•Ex. Icthyosaur, dolphin, & shark;
•crocodile vs phytosaurs
-Semi-aquatic predator niche
•Marsupial vs placentals |
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Term
The Hardy-Weinberg Principle
Species |
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Definition
–A group of interbreeding populations, reproductively isolated from other populations.
•Horse & Donkey = Mule? |
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Term
The Hardy-Weinberg Principle
Population |
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Definition
| –members of species that occupy the same geographical region |
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Term
The Hardy-Weinberg Principle
Population genetics |
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Definition
| –The study of the properties of genes in populations. |
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Term
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Definition
| –The proportion of alternative forms of a gene (alleles) in a population can be calculated and the allele frequencies determined |
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Term
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Definition
| –Alternate forms of a gene |
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Term
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Definition
–The proportion of alleles of a given gene
–Ex. # of blue eyes vs # of brown eyes |
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Term
| Hardy Weinberg Equilibrium |
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Definition
•Dominant alleles do not replace recessive ones
•The proportions stay the same!
•A population that is in Hardy-Weinberg equilibrium is not evolving.
•Assumptions
–Population size is infinite
–Mating is random
–No mutation
–No input of new copies of any allele from any extraneous source (such as
from a nearby population or from mutation).
–All alleles are replaced equally from generation to generation (natural selection is not occurring) |
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Term
| Why Do Allele Frequencies Change |
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Definition
Change in the population
–Mutation, migration, genetic drift, nonrandom mating, selection
–Mutation
•alterations in DNA nucleotide sequences
•add new combinations to the genetic makeup of a population.
–Migration
•movement of individuals into or out of the population can be a source of new genetic variation.
–Genetic Drift
•In small populations, by random chance alone, it is possible for the allele frequencies to change from one generation to the next.
•As local subgroups are isolated from the main population, genetic drift occurs in them as well.
•The Founder Effect
–a few individuals are separated from the rest and give rise, over time, to a new population
–this effect often occurs on oceanic islands where a species may have descended form one or two founders.
•Bottleneck Effect
–a few members of a population of species are all that are left to give rise to the next generations of that species.
–limits the genetic diversity of a population and can lead to the appearance of recessive mutations.
–Cheetahs are all practically genetically identical and may have passed through a genetic bottle-neck.
–Nonrandom Mating
•Nonrandom mating and inbreeding (mating with relatives) also lead to changes in gene frequencies from one generation to the next.
–Inbreeding produces more homozygous individuals than predicted by the Hardy-Weinberg Rule.
•-Ex. Self fertilizing plants
•More likely to receive Homozygous defects!
–Selection
•Some individuals leave behind more progeny than others.
–Artificial Selection
•Breeder selects desirable traits
–Natural Selection
•Nature
•Operates to select certain fit phenotypes, which add more genes to successive generations. |
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Term
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Definition
| Selection changes the population when genotypes are favored. |
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Term
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Definition
–individuals toward the middle of the range are selected.
•Ex. Humans born with intermediate birth wait have the the highest survival rates |
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Term
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Definition
–Directional selection favors a phenotype at one extreme or the other of the population.
•Ex. Phototropism in Drosophila |
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Term
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Definition
–both extremes are favored to the demise of the middle phenotype.
–less common than other types |
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Term
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Definition
Is a recombinant DNA procedure that seeks to treat disease by altering the genes of the afflicted person.
The mutant version of a gene is replaced with a properly functioning one. |
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