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Homunculus How is “heredity passed on: Spermist vs Ovists Spermist conception of a human sperm
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Homunculus Leeuwenhoek’s black male and white female rabbit experiments: spermist “proof”
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Gregor Mendel Mendelian Genetics
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Mendel’s Three Principles Dominance Segregation Independent Assortment The foundation of “classical” science (1822-1884)
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Dominance Traits of both parents inherited, but one shows over the other Traits are not blended
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Dominance Mechanism Two alleles are carried for each trait In true-breeding individuals, both alleles are the same. Hybrids, on the other hand, have one of each kind of allele. One trait is dominant, the other trait is recessive
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Segregation Half the gametes (egg or sperm) will carry the traits of one parent and half the traits for the other parent Pairs of alleles are separated (=segregated) during meiosis
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Two different parental characteristics will be inherited independently of one another during gamete formation. Example: flower color and leaf shape
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Human Genome Project U.S. govt. project coordinated by the Department of Energy and the National Institutes of Health, launched in 1986 by Charles DeLisi. Definition: GENOME – the whole hereditary information of an organism that is encoded in the DNA. Project Goal: to identify the approximate 100,000 genes in the human DNA. -determine the sequences of the 3 billion bases that make up human DNA. -store this information in databases. -develop tools for data analysis. -address the ethical, legal, and social issues that arise from genome research.
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Bacteria (E. coli, influenza, several others) Yeast (Saccharomyces cerevisiae) Plant (Arabidopsis thaliana) Fruit fly (Drosophila melanogaster) Mouse (Mus musculus) Modeled Organisms
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Craig Venter Celera Genomics
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Importance of genetics Understanding hereditary diseases and to develop new treatmentsUnderstanding hereditary diseases and to develop new treatments Donor matchesDonor matches PaternityPaternity ForensicsForensics EvolutionEvolution MigrationMigration
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Polynesian Origins Bismarck Archipelago 3.5ka http://www.sciencedaily.com/releases/2011/02/110203124726.htm mtDNA
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Polynesian Origins
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Genetic Testing Would you want to know? Ethical concerns Cost Insurance companies
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Difference between Meiosis and Mitosis
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Meiosis I Interphase Prophase IMetaphase IAnaphase ITelephase I
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Crossing Over of Nonsister Chromatids between Homologous Chromosomes
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Meiosis II Prophase IIMetaphase IIAnaphase IITelephase II
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Genetic Testing
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Gel electrophoresis
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PCR way of copying specific DNA fragments from small sample DNA material "molecular photocopying" It’s fast, inexpensive and simple Polymerase Chain Reaction
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Genetic Testing Paternity Test $99 $299, looks at specific diseases 23 and me
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Genes- genetic material on a chromosome that codes for a specific trait Genotype- the genetic makeup of the organism Phenotype- the expressed trait Allel- an alternative form of a gene Genetic Definitions
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Dominance Mechanism Two alleles are carried for each trait In true-breeding individuals, both alleles are the same (homozygous). Hybrids, on the other hand, have one of each kind of allele (heterozygous). One trait is dominant, the other trait is recessive
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Genetic Information Genes are traits “Eye color” Ear lobe connectedness Genes produce proteins Enzymes are proteins
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Homologous Chromosomes allele: specific trait gene: location
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Allele Example Gene = “eye color” Alleles brown blue green lavender
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Allele Examples appearance eye color: homozygous B B
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Allele Examples appearance eye color: heterozygous, brown dominant over blue Bb
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Genotype vs Phenotype homozygous (dominant) heterozygous homozygous (recessive) genotype phenotype appearance B B B b bb
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Punnett Square If male & female are heterozygous for eye color X brown:3/4 offspring blue:1/4 offspring male female b b B B B B B B B B b b b b b b
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PKU Each parent carries one gene for PKU. Pp Pp X P p pP P P P p p P p p Possible genotypes: 1PP 2Pp 1pp Possible phenotypes:no PKUPKU
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Compare this to what would have happened if one parent was homozygous for sickle cell. HbA HbS X HbA HbS HbA HbS HbA HbS HbA all offspring are carriers of sickle cell trait
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Where Does Genetic Diversity Come From? b b Mutation b b Chromosomal Aberrations b b Genetic Recombination (e.g., from sexual reproduction) b b Mutation b b Chromosomal Aberrations b b Genetic Recombination (e.g., from sexual reproduction)
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mutation Sickle Cell Mutation CTG ACT CCT GAG GAG AAG TCT Leu Thr Pro Glu Glu Lys Ser CTG ACT CCT GAG GTG AAG TCT Leu Thr Pro Glu Val Lys Ser NORMAL Hb SICKLE CELL
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Autosomes and Sex Chromosomes
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Red-Green Color Blindness Sex-linked trait XCXC Y XCXC XcXc X XCXC XcXc YXCXC XCXC XCXC XCXC Y XcXc XCXC Y XcXc Normal male Normal female recessive gene Possible outcomes:X C X C X C X c X C YX c Y Normal female Normal Female (carrier) Normal male Color-blind male
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Eunconnected earlobe econnected earlobe Eunconnected earlobe econnected earlobe allele gene PEE x ee gametes E e F1F1 unconnected connected
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F1F1 Ee x Ee gametes 1/2 E 1/2 e E e Ee EEEe ee F2F2 1 EE 2 Ee 1 ee Punnett Square
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Genotypes Phenotypes Experiment to determine dominant vs. recessive
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Genetic Sleuthing My eye color phenotype is brown. What is my genotype?
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Complexities Multiple genes for one trait Example: eye color Blended traits (“incomplete dominance”) Influence of the environment (UV, smoking, alcoholism)
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Complexities Co-dominance-neither allele is recessive and the phenotypes of both alleles are expressed. Blood types- AB (not O); sickle cell anemia heterochromia
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Disorders Down’s Syndrome (chrom 21) Huntington’s (chrom 4) Alzheimer’s (chrom 1, 10, 14, 19, 21)
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Tongue Roller R = Tongue Roller r = Unable to Roll Tongue
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Widow’s Peak W = Widows Peak w = Lack of Widow’s Peak
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Free Ear Lobe Attached Ear Lobe E = Free Ear Lobe e = Attached Ear Lobe
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Hitchhiker’s Thumb Hi = Straight Thumb hi = Hitchhiker’s Thumb
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Bent Little Finger Bf = Bent Little Finger bf = Straight Little Finger
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Mid-digital Hair M = Mid-Digital Hair m = Absence of Mid-Digital Hair
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Dimples D = Dimples d = Absence of Dimples
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Short Hallux Ha = Short Hallux ha = Long Hallux
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Short Index Finger S s = Short Index Finger S 1 = Long Index Finger *Sex-Influenced Trait
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http://www.youtube.com/watc h?v=gCPuHzbb5hA
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