Presentation on theme: "5/11/20151 Genetic Fundamentals & Gregor Mendel Dr. Rick Woodward Chapters 9 & 10 (New/Green Text Book)"— Presentation transcript:
5/11/20151 Genetic Fundamentals & Gregor Mendel Dr. Rick Woodward Chapters 9 & 10 (New/Green Text Book)
5/11/20152 January 12, 2011 Wednesday Today’s Agenda: -Journal Questions: Why do you think the study of genetics is important? What is your New Year’s resolution/goal? -Turn in your gene mutation winter break project. *1. Lecture: Genetics & Mendel’s Laws –Slide 36 2. Genetic Traits Activity: How alike are we? 3. Work on page 43 in packet: Heredity 4. Video: “Ghost in your genes” 5. Homework: Read Chapter 9 “Mendel Genetics” (page 164 - 183: Second page of packet)
5/11/20153 The Genesis of Genetics A. Genetics was founded with the work of Gregor Johann Mendel, an Austrian monk who experimented with garden peas.
5/11/20155 Situating Mendel Historically (1831-1836) (1859) (1866) (1892) (1910) Darwin on Darwin’s Mendel’s Weismann’s Morgan Mendel bornBeagle On the Origin Paper germ plasm finds white Voyage of Species published theory fruit fly 1800 1815 1830 1845 1860 1875 1890 1905 1920 Napoleon CrimeanFormation Mendel’s Sex defeated at Warof German work re- chromo- Waterloo (1853-1856)Empire (1870)discovered somes
5/11/20156 Genetic Terminology Key Concept! A. Heredity is the transmission of characteristics from parents to offspring. B. A trait is a specific characteristic such as height or eye color.
5/11/20157 Genetics Terminology C. Molecular genetics is the study of the structure and function of chromosomes and genes.
5/11/20158 Mendel’s Observations A. Mendel observed seven characteristics in pea plants. B. He looked at contrasting traits: 1. Plant height (long or short stems) 2. Seed color (yellow or green) 3. Flower color (purple or white)
5/11/201515 Mendel’s Observations G. When the plants matured, he recorded the number of each type of offspring produced by the P 1 plant. (1) He called the offspring of the P1 generation the first filial generation, or F1 generation.
5/11/201516 F1 x F1 Punnett square F2 genotypes 1/4 SS 1/2 Ss 1/4 ss F2 phenotypes 3/4 smooth 1/4 wrinkled
5/11/201517 Terminology A. An allele is an alternative form of a gene. (1) Letters are used to represent alleles. (i.e. T, t) (2) Dominant Trait: TT (Tallness) (3) Recessive Trait: tt (shortness) B. Gene: a segment of DNA that contains coding for a polypeptide or protein; a unit of heredity information.
5/11/201518 Terminology C. Punnett Square: Used for predicting the probability that certain traits will be inherited by offspring. (1) Punnett Square = P for Probability
5/11/201519 Terminology D. Homozygous: When both alleles of a pair are alike, or the same, the organism is said to be homozygous for that characteristic. AA = RED aa = BLUE
5/11/201520 Terminology E. Heterozygous: When the two alleles in the pair are different, the organism is heterozygous for that characteristic. Tt
5/11/201521 Terminology F. The genetic makeup of an organism is its genotype (1) Combination of alleles (Rr, rr, RR)
5/11/201522 Genotypic Ratio 1. Cross (Tt) (Tt) using a Punnett square. 2. What is the genotypic ratio? Genotypic Ratio = 1TT:2Tt:1tt
5/11/201523 Terminology G. Phenotype is the physical appearance or expression of the genotype. (Flower Color) (1) Flower Color is the physical appearance/phenotype.
5/11/201524 Phenotypic Ratio 1. What is the phenotypic ratio of a cross between (Tt)(Tt)? - Use a Punnett Square to assist you. 2. The phenotypic ratio is 3 Tall: 1 Short
5/11/201525 Ratios F1 x F1 crosses: Mendel also discovered that traits that disappear in the F1 generation reappear in the F2 generation in a 1:3 ratio.
5/11/201526 Hybrids A. A hybrid is….. B. A monohybrid cross is a cross between individuals that involves one pair of contrasting traits (TT)(tt) C. A Dihybrid cross is a cross between individuals that involve two pairs of contrasting traits. (BBSS) (ssbb)
5/11/201531 Recessive Traits versus Dominant Traits A. Recessive Trait: Referring to an allele that is masked by the presence of another allele for the same characteristic. (1) Example: T = Tall t = Short tt = Short (recessive trait)
5/11/201532 Recessive Traits versus Dominant Traits
5/11/201533 Recessive Traits versus Dominant Traits B. Dominant Trait: The dominant trait dominants over a recessive trait unless the recessive trait is homozygous tt = shortness. (1) Example: T = Tall t = Short TT = Tall (Dominant Trait) Tt = Tall (Dominant Trait)
Epigenetics A. May control the expression of our genes. B. Involves the modifications of the activation of certain genes, but not the basic structure of DNA C. Possible Epignetic Processes: 1. Gene silencing 2. Chromosome inactivation 5/11/201535
5/11/201537 Today’s Activity: HOW ALIKE ARE OUR ALLELES? Find out the alleles you have for different traits Find out the alleles you have for different traits For each trait, write down whether you express that trait and whether you are dominant or recessive.
5/11/201538 1. TONGUE ROLLING DOMINANT Trait: The ability to roll up the sides of the tongue (RR, Rr) RECESSIVE Trait: Not being able to roll up the sides of the tongue (rr) Not being able to roll up the sides of the tongue (rr)
5/11/201539 2. 2nd TOE LENGTH DOMINANT Trait: DOMINANT Trait: 2nd toe is longer than the big toe 2nd toe is longer than the big toe (BB, Bb) RECESSIVE Trait: RECESSIVE Trait: 2nd toe is shorter than the big toe 2nd toe is shorter than the big toe(bb) -note the presence of a toe ring.
5/11/201540 3. WIDOW’S PEAK DOMINANT Trait: DOMINANT Trait: Hairline has a point, widow’s peak is present Hairline has a point, widow’s peak is present (WW, Ww) RECESSIVE Trait: RECESSIVE Trait: Hairline has no point, no widow’s peak Hairline has no point, no widow’s peak(ww)
5/11/201541 4. ATTACHED/FREE EARLOBES DOMINANT Trait: DOMINANT Trait: Earlobes hang freely from the ear Earlobes hang freely from the ear (EE, Ee) (EE, Ee) RECESSIVE Trait: RECESSIVE Trait: Earlobes are attached to the side of the face Earlobes are attached to the side of the face(ee)
5/11/201542 5. HITCHHIKER’S THUMB DOMINANT Trait: DOMINANT Trait: Thumb is straight slightly angled Thumb is straight slightly angled (HH, Hh) RECESSIVE Trait: RECESSIVE Trait: Thumb can be bent backwards Thumb can be bent backwards(hh)
5/11/201543 6. HAIRY KNUCKLES DOMINANT Trait: DOMINANT Trait: No hair on middle parts of fingers (HH, Hh) RECESSIVE Trait: RECESSIVE Trait: Hair is present on middle parts of fingers (hh)
5/11/201545 8. CLEFT CHIN DOMINANT Trait: DOMINANT Trait: No cleft present in the chin No cleft present in the chin (CC, Cc) RECESSIVE Trait: RECESSIVE Trait: Chin has a cleft or indentation Chin has a cleft or indentation(cc)
5/11/201546 9. STRAIGHT/BENT PINKIES DOMINANT Trait: Pinkies are straight (SS, Ss) RECESSIVE Trait: RECESSIVE Trait: Pinkies are bent Pinkies are bent(ss)
5/11/201549 January 13, 2011: Thursday Today’s Agenda: -Journal Question: What is the difference between a genotype and a phenotype? -What is epigenetics? *(1) Lecture on Mendel’s Laws (finishing unit) –slide 85 (2) Start Face Lab (last pages of your packet.) (3) HW: Finish pages 44, 46, 48 in your packet. (4) Study guide given out next class. -Bring flash cards if you need them. (5) Exam next week on Mendel & Genetics -All work is due on the day of the exam
5/11/201550 Mendel’s Laws & Other Key Concepts 1. Mendel’s Law of Segregation 2. Mendel’s Law of Independent Assortment 3. Mendel’s Law of Dominance 4. Mendel’s Law of Incomplete Dominance Other Key Concepts: 1. Blood Types 2. Homologous Chromosomes 3. Crossing Over 4. Sex-Linked Traits (pedigree chart) 5. DNA versus RNA
5/11/201551 Mendel’s Law of Segregation A. Law of Segregation states that a pair of factors (alleles) is segregated, or separated, during the formation of gametes (reproductive cells) (1) When two gametes combine during fertilization, the offspring have two factors controlling a specific trait (Gg)
5/11/201553 Law of Segregation and Recombination A. Each trait is transmitted as an unchanging unit, independent of other traits, thereby giving the recessive traits a chance to recombine and show their presence in some of the offspring.
5/11/201554 Mendel’s Law of Independent Assortment 1. Traits are not inherited together. 2. In forming the gametes, the “Factors” for any two traits assort independently from one another 3. This became known as Mendel’s second principle: Independent Assortment
5/11/201561 What are Blood Types? Everybody has a blood type. The most common blood type classification system is the ABO (say "A- B-O") system discovered by Karl Landsteiner in the early 1900s. There are four types of blood in the ABO system: A, B, AB, and O. Your blood type is established before you are born, by specific genes inherited from your parents. You receive one gene from your mother and one from your father; these two combine to establish your blood type. These two genes determine your blood type by causing proteins called agglutinogens (a-GLOO-tin-a-gins) to exist on the surface of all of your red blood cells.
5/11/201569 Homologous Chromosomes B. Homologous pairs of chromosomes segregate during meiosis.
5/11/201570 Crossing Over A. Portions of chromatids may break off and attach to adjacent chromatids on the homologous chromosome = a process called crossing over.
5/11/201571 Sex-Linked Traits A. Sex-linkage is the presence of a gene on a sex-chromosome. B. Sex Chromosomes: XX = Female XY = Male C. X-Linked Traits: (1) Colorblindness (2) Hemophilia (3) Duchenne Muscular Dystrophy
5/11/201584 Face Lab (January 18, 2011) - Journal Question: What genetic traits do you think that you get from your parents? (Name/Identify 2 traits) 1. Find a friend to perform today’s lab with. 2. Lab: Data Table & Diagram Your Results. (Last pages of your packet) -Diagram your offspring as a teenager. (use color pencils) 3. Write a brief biography of your teen. 4. Homework: Finish your packet & Face Lab Portrait
5/11/201585 Today’s Lab Find a partner to work with and perform the face lab on human genetics. Materials: 1. Coin (Heads = Dominant. Tails = Recessive) 2. Lab 3. Color Pencils and paper to diagram face.
5/11/201586 Today’s Lab 1. Each of you must diagram a portrait of your child as a teenager. 2. Name your child 3. On the back of your portrait write a brief life history of your child.
Today’s Agenda January 20, 2011 Journal Questions: -How do the nitrogen bases pair up in DNA? -What are the three parts of a nucleotide? *1. Brief Lecture: DNA Replication 2. Complete Face Lab –Draw your teen and write a brief biography. 3. Work on Study Guide for Exam VI 4. Exam on Monday (Jan. 24, 2011) 5/11/201587
DNA Replication A. The process of copying DNA in a cell is called replication. (1) During replication, the two nucleotide chains separate by unwinding, and each chain serves as a template for a new nucleotide chain. 5/11/201588
Steps of DNA Replication (1) Separation of two nucleotide chains. a. Point of separation = Replication fork (2) Chains are separated by enzymes called helicases. (3) Helicase enzymes move along the DNA molecule, they break the hydrogen bonds between the complementary bases, and the chains separate. 5/11/201590
Steps of DNA Replication (4) DNA Polymerases bind to the separated chains of DNA. 5/11/201591
Steps of DNA Replication (5) As DNA Polymerases move along the separated chains, new chains of DNA are assembled using nucleotides that are complementary to the existing DNA chains. 5/11/201592
Steps of DNA Replication (6) The complementary nature of the two chains of DNA is the foundation for accurate DNA replication. -Nitrogen Base Pairing Rules: A – T C – G GATTACA CTAATGT (Complementary Strand) 5/11/201593
DNA Replication When DNA replication is completed, (1) Two new exact copies of the original DNA molecule are produced (2) The cell is now ready to undergo cell division (P.M.A.T). 5/11/201594
5/11/201595 Next Topics for the End of the Semester: January 27, 2011 (Thursday) 1. Gene Mutations 2. DNA Replication 3. Recombinant DNA Technology 4. Protein Synthesis -Comprehensive final exam with emphasis on genetics, the cell, organelles and their functions.