Heredity B 2013 KAREN LANCOUR HEREDITY NATIONAL SUPERVISOR

Heredity (B) -2013 KAREN LANCOUR HEREDITY NATIONAL SUPERVISOR karenlancour@charter. net

Event Rules – 2013 DISCLAIMER This presentation was prepared using draft rules. There may be some changes in the final copy of the rules. The rules which will be in your Coaches Manual and Student Manuals will be the official rules.

Event Rules – 2013 n BE SURE TO CHECK THE 2013 EVENT RULES FOR EVENT PARAMETERS AND TOPICS FOR EACH COMPETITION LEVEL

TRAINING MATERIALS n n n Training Power Point – content overview Training Handout - content information Sample Tournament – sample problems with key Event Supervisor Guide – prep tips, event needs, and scoring tips Internet Resource & Training CD’s – on the Science Olympiad website at www. soinc. org under Event Information Biology-Earth Science CD, Genetics CD (new) for Genetics CD (new) Heredity and Designer Genes as well as the Division B and Division C Test Packets are available from SO store at www. soinc. org

Heredity (B) n n Content n Basic principles of genetics n Some possible areas – dominant, recessive, incomplete dominance, co-dominance, monohybrid & dihybrid crosses, test cross, multiple alleles, sex-linkage, genotype, phenotype, epistasis, mutations, multifactorial traits, pedigrees, karyotypes, mitosis, meiosis, nondisjunction, genetic disorders, DNA structure and replication, transcription, translation, common genetic disorders Process Skills – data analysis, predictions, calculations, inferences, observations

Possible Topics for Various Levels Regional & State Monohybrid cross Regional & State National (all topics) Dihybrid cross Pedigree construction and analysis Sex-linked traits Production of gametes with Abnormal #’s of chromosomes Genotype vs. phenotype Pedigree analysis Trihybrid cross (probability analysis) Human sex determination Multiple alleles Analysis of karyotypes for deletion, addition, translocation Gene: protein relationship DNA structure & replication Transcription and translation Mitosis Meiosis and gamete formation Multifactorial traits Human karyotypes analysis for nondisjunction disorders Co-dominance & Incomplete Dominance Epistasis Dominant and recessive alleles

PRINCIPLES OF GENETICS n GENES – come in pairs § § n n Section of DNA – codes protein or part of protein One from each parent ALLELE – different forms of a gene MULTIPLE ALLELES – more than 2 forms of a gene HOMOZYGOUS – same alleles HETEROZYGOUS – different alleles

Dominant vs. Recessive n Dominant – always expressed v v v n Capital letters – N Homozygous - NN Heterozygous - Nn Recessive – Recessive prevented by dominant v v Lower case letters – n Homozygous – nn Punnett Square – Box showing allele combinations

Dominant and Recessive n Autosomal Dominant gene on an autosome n Autosomal Recessive gene on an autosome n Sex-linked Dominant gene on a sex chromosome n Sex-linked Recessive gene on a sex chromosome

Monohybrid Cross Hybrid – Ss X Ss Hybrid One Trait – Smooth vs One Trait wrinkled Two gametes per parent S and s Punnett Square with 4 Punnett Square boxes – 4 offspring

Genotype & Phenotype Genotype Phenotype SS or Ss Round ss Wrinkled Genotype frequency 1: 2: 1 Phenotype frequency 3: 1

Dihybrid Cross Dihybrid – 2 traits Dihybrid Gametes per parent = Gametes per parent 4 Punnett Square – 16 Punnett Square boxes Genotype ratio 1: 2: 4: 2: 1 Phenotype ratio 9: 3: 3: 1

Incomplete Dominance n n Hybrid is a blend of two traits Genotype frequency 1: 2: 1 Phenotype frequency 1: 2: 1 Examples: Examples Flowers, Animal fur

Co-dominance n n n More than one dominant allele Blood types – A, B, O alleles Phenotypes Genotypes A I AI A or I Ai B IBIB or IBi AB I AIB O ii

Co-dominance n n co-dominance – both dominant alleles (genes) in an individual are expressed as blood types A and B genes are co-dominant and both dominant over the O gene which is recessive

ABO Blood System

Independent Assortment vs. Linkage n n Independent Assortment – genes on different chromosomes separate independently during meiosis Linkage – genes on the same chromosome are inherited as a group v Autosomal linkage – on autosomes v Sex-linked – on sex chromosomes

Linkage – Sex Linkage n n n Linkage – genes on the same chromosome inherited as a group Sex-linkage – genes on sex chromosomes (esp. X) Y-chromosome shorter – some genes from X missing X-linked traits more common in men X-linked traits Men get X-chromosome from mom Red-green colorblindness, hemophilia

Environmental influence on genes expression n Gene function is influenced by environment as with identical twins Genes have blueprint for proteins or parts of proteins Proteins can be structural proteins (parts of body) or functional proteins (hormones/enzymes)

Epistasis and Multifactorial Inheritance n n Epistasis - the interaction between two or more genes to control a single phenotype Multifactorial inheritance - many factors (multifactorial) both genetic and environmental are involved in producing the trait or condition. Examples: height, weight, cleft palate, spina bifida

Pedigree Symbols n Generations = I – Original Parents, II- F 1 (children), III – F 2 (grandchildren)

Pedigree – Curly vs Straight Hair Types of Analysis n Relationships n Dominant Gene – H Curly n Recessive Gene – h Straight n Genotypes n Phenotypes

Karyotypes n Pairs 1 -22 =Autosomes XY = Sex chromosomes Male = X & Y Female = only X n Nondisjunction n Extra chromosomes n n n (Trisomy) n Missing chromosomes (Monosomy)

Cell Cycle n Interphase v v v n G 1 S – DNA replicates G 2 Mitosis v v Prophase Metaphase Anaphase Telophase

Mitosis vs Meiosis n Mitosis Growth and Asexual Reproduction v One division – 2 diploid cells v Genetically same as original v n Meiosis Gametes for Sexual Reproduction v 2 divisions – 4 haploid cells v

DNA Structure n n n Double helix Antiparallel – 3’ to 5’ Antiparallel Nucleotide v v v Deoxyribose sugar Phosphate Nitrogen bases Ø Adenine Ø Thymine Ø Guanine Ø Cytosine

DNA Replication n n n Replication (in Replication nucleus) DNA uncoils & splits DNA Reads 3’ to 5’ Reads Assembles 5’ to 3’ Assembles 4 types of 4 types nucleotides Okazaki fragments Okazaki

Types of RNA n n Differences between DNA & RNA v Single strand v Ribose instead of Deoxyribose v Uracil instead of Thymine Messenger RNA – carries blueprint Transfer RNA – brings amino acids Transfer RNA Ribosomal RNA – reads code Ribosomal RNA

Transcription & Translation n n Transcription – makes RNA (in nucleus) Translation (protein synthesis) -Reads Translation (protein synthesis) blueprint and makes protein or part of protein (in cytoplasm at the ribosome)

Transcription of RNA from DNA n n n Transcription: Synthesis of RNA from a DNA Template. Requires DNA-dependent RNA polymerase plus the four nucleotides (ATP, GTP. CTP and UTP). Synthesis begins at a the initiation site on DNA The template strand is read 3' to 5' and the m. RNA is synthesized 5' to 3'

Translation – Protein Synthesis

Mutations n n Mutation – any change in the DNA Gene mutation Chromosomal mutation Agents causing mutations – radiation, chemicals, excess heat