Heredity

Science Olympiad Coaches ClinicHeredity: 

Carolina Biological Supply Company Science Olympiad Coaches Clinic Heredity Will Martin Biologist/Product Developer

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Objectives

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What to Expect This event may be run as stations Contestants will be given genetics word problems, pedigrees, karyotypes, or diagrams Students should have a non-programmable calculator, and nothing else

Possible Topics for Various Levels : 

Possible Topics for Various Levels

Vocabulary: 

Vocabulary Gene: The basic physical unit of heredity -An individual has 2 genes for every trait (one from mom, one from dad) Phenotype: The observable traits of an organism Genotype: Genetic makeup of an organism Allele: One member of a pair of genes that occupies a certain space in the genome Homozygous: Having 2 of the same alleles Heterozygous: Having 2 different forms of an allele Genome: The total genetic content of an individual Mitosis: Produces 2 daughter cells, identical to the parent Meiosis: Produces 4 daughter cells, each with half the number of chromosomes as the parent

Dominant vs. Recessive : 

Dominant vs. Recessive Dominant – always expressed Capital letters – N Homozygous - NN Heterozygous - Nn Recessive – prevented by dominant Lower case letters – n Homozygous - nn

Basic Crosses and Dominance/Recessiveness: 

Basic Crosses and Dominance/Recessiveness You should be able to follow dominant, recessive, and sex-linked traits from the Parental generation to the F2 Example 1: The dominant allele R produces purple kernels in corn, while the recessive allele r produces yellow kernels. What is the genotypic ratio that results from 2 homozygous parent ears being crossed? What is the phenotypic ratio that results from 2 homozygous parent ears being crossed? Be able to carry this out all the way to the F2 generation P0: R/R X r/r F1: R/r F2: 1 R/R: 2 R/r: 1 r/r 3 R/- : 1 r/r

Basic Crosses and Dominance/Recessiveness: 

Basic Crosses and Dominance/Recessiveness Example 2: Again, Purple (R) is dominant to Yellow (r), but now we also have Starchy (Su) which is dominant to Sweet (su) P0: r/r, Su/Su X R/R, su/su (Yellow Starchy X Purple Sweet) F1: All heterozygous R/r, Su/su What is the phenotype here? F2: 9 Purple Starchy (R/- Su/-): 3 Purple Sweet (R/- su/su): 3 Yellow Starchy (r/r Su/-): 1 Yellow Sweet (r/r su/su)

Sex-Linked Traits: 

Sex-Linked Traits These traits are passed on the sex chromosomes, And will differ in their P0, F1, and F2 ratios. Example: White eyes in Drosophila are a sex-linked recessive condition. P0:White female (xx) X Wild type male (XY) F1:All females heterozygous wt (Xx), all males white-eyed (xY) F2:Half females white, half wt, half males white, half wt The overall ratio is 1 white: 1 wild type

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Incomplete Dominance Red (R/R) X White (r/r) F1: All Pink (R/r) How is this different from simple Mendelian? F2: What are the phenotype and genotype frequencies? Both are 1:2:1 Adapted from Karen Lancour’s Presentation

Resources: 

Resources Types of Human Chromosome Abnormalities BioKit Includes 90 human karyotype forms, 30 Biophoto® Sheets of normal male, and 10 Biophoto® Sheets of the following:  Trisomy 21 Down Syndrome (autosomal nondisjunction) 14/21 Translocation Carrier (translocation) 5p Deletion (cat cry syndrome) Klinefelter Syndrome (sex chromosome nondisjunction) Turner Syndrome (missing chromosome) Fragile X Syndrome (broken chromosome; nonbanded stain) 17-3824

Co-dominance : 

Co-dominance

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ABO Inheritance Type A Type B Type AB Type O Type A Type B

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Co-Dominance Resources CarolinaTM Blood Group Genetics With Synthetic Blood Students solve a case of disputed inheritance Covers multiple alleles, co-dominance, and the relationship between genotype and phenotype 70-0107

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DNA Structure Chargaff’s Rules: Amount of (A)= Amount of (T) Amount of (G)= Amount of (C) Amount (A+G)= Amount (C+T) Amount (C+G)= Amount (A+T)

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DNA Structure Have students build their own DNA base. Be sure to stress the difference in bonding angles on the purple sugar molecule. 1300 1000

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Putting It All Together: Two students may then team up to create DNA base pairs with the addition of hydrogen bonds Note the number of hydrogen bonds between the nitrogenous bases Thymine and adenine share 2 hydrogen bonds Guanine and cytosine share 3 hydrogen bonds

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Materials for DNA Double Helix Models: Carolina DNA Structure and Function Kit -makes 30 single nucleotide bases and 15 nucleotide base pairs. Color coded Teacher Manual and Student Guide Easy parts identification and assembly. Catalog # 21-1113 $42.50

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Differences between DNA and RNA Adapted from Dr. Bill Wellnitz Presentation

Transcription vs. Translation: 

Transcription vs. Translation Central Dogma DNA Transcription RNA Translation Protein Transcription: Making RNA from a DNA template in the nucleus Translation: Making Protein from RNA in the cytoplasm

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Translation-National Level Definition: Process of making proteins from amino acids and mRNA Requires GTP instead of ATP Reading windows are in groups of 3 Be able to use the genetic code to produce amino acids KNOW START/STOP CODONS

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Mutations Types of Mutations Frameshift: Tis The Sea Son Tis heS eaS on Nonsense: Premature Termination AUG CCA UCG CCA UAG AUG CCA UAG Missense: Change one AA to another Example: Sickle Cell: Glutamic Acid to Valine

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Carolina Biological Supply Company Thanks you for your time and continued dedication to teaching hands-on science in your classrooms. ENJOY the rest of the Science Olympiad Coaches Clinic here at NC State! Will Martin will.martin@carolina.com