AP BIO Please pick up the following papers on the counter by the door as you come into the room: Genetics – Chapter 11 Reading Guide Blood Type Worksheet Pedigree Worksheet

Mendelian Genetics CHAPTERS 11 & 12 WAKEFIELD 2015

Goals - Identify Mendel’s scientific approach to the laws of inheritance and probability and its physical basis in the behavior of alleles and chromosomes Communicate the complexity predicted by Mendelian genetics Relate the chromosomal basis of genetic disorders

Scales- 4)Using the concepts of Mendelian genetics, students will be able to predict heritable factors from true-breeding, hybridization and mutations then apply these predictions to populations and evolutionary processes. 3)Using the concepts of Mendelian genetics, students will be able to predict heritable factors from true-breeding, hybridization and mutations then apply these predictions to populations. 2)Using the concepts of Mendelian genetics, students will be able to predict heritable factors from true-breeding, hybridization and mutations 1)Students may need assistance in using the concepts of Mendelian genetics to predict heritable factors from true-breeding, hybridization and mutations

Gregor Mendel – 1860’s  Developed fundamental principals of inheritance & the laws of segregation  Used garden peas  Many varieties  Fertilization is easily controlled  Offspring characteristics can be quantified  2 laws of inheritance  Law of Segregation  Law of Independent Assortment

Gregor Mendel – 1860’s  Studied 7 characters or heritable features we now call alleles or traits  Used true-breeding (homozygous) plants  Performed hybridization by cross-pollinating to create hybrids (heterozygous) plants  Quantified by their qualitative traits  P Generation – F 1 Generation –F 2 Generation

Law of Segregation  Alternate forms of alleles (genes) account for qualitative variations in offspring  Organisms have 2 copies of each allele (gene) for each trait  When 2 different alleles occur together, one will be dominant and one will be recessive  Allele pairs segregate during gamete formation (Mendel’s Law of Segregation)

Punnett Square  Used to quantify the qualities of offspring and to predict future offspring  Dominant offspring designated by capital letter  Recessive offspring designated by small case letter

Monohybrid cross – complete the Punnett Square for the following cross: Parent 1 – Tall homozygous pea plant Parent 2 – Short homozygous pea plant

Punnett Square  What is the phenotypic ratio?  What is the genotypic ratio?  What prediction can you make based on this type of cross?

Monohybrid cross – complete the Punnett Square for the following cross: Parent 1 – Tall heterozygous pea plant Parent 2 – Short pea plant

Punnett Square  What is the phenotypic ratio?  What is the genotypic ratio?  What prediction can you make based on this type of cross?

Monohybrid cross – complete the Punnett Square for the following cross: Parent 1 – Tall heterozygous pea plant Parent 2 – Tall heterozygous pea plant

Punnett Square  What is the phenotypic ratio?  What is the genotypic ratio?  What prediction can you make based on this type of cross?

Explain how a test cross might be done and what would it effectiveness be?

Law of Independent Assortment  Each pair of alleles segregates independently of every other pair of alleles  Important in dihybrid crosses  Applies to genes located on different chromosomes or close or far apart on the same chromosome

Parent 1 Homo – Tall Hetero – Yellow Parent 2 Hetero – Tall Hetero - Yellow Create a Punnett Square showing the parental alleles, their potential allele combinations and the phenotypic and genotypic ratios of the cross

Punnett Square  What is the phenotypic ratio?  What is the genotypic ratio?  What prediction can you make based on this type of cross?

Inheritance Patterns  Dominant / Recessive  One allele will mask the other allele in a pair  Dominant allele is evident in the phenotype

Inheritance Patterns  Incomplete Dominance  Neither allele is dominant  Phenotype will be a blend of the two alleles  Complete the following crosses & give phenotypes & genotypes:  Homozygous red X homozygous white  Pink X Pink

Inheritance Patterns  Codominance – neither allele is dominant over the other – both phenotypes will be present in the offspring  Complete the following crosses giving the phenotypes and genotypes:  White chicken X black chicken  Cross 2 speckled chickens

Blood Types – Explain the inheritance pattern  Blood types – GenotypeBlood Type (Phenotype)Blood Proteins PresentBlood Antibodies Present i Type ONoneAnti-A and Anti-B I A Type AAAnti-B I A iType AAAnti-B I B Type BBAnti-A I B iType BBAnti-A I A I B Type ABA and BNone

Blood Types  Practice on the blood type scenario problems on your hand out -

Hereditary Multiplication & Addition Rules  Applied to monohybrid crosses  States:  The probability that a certain combination of independent events will occur together is equal to the product of the separate probability of the independent events  The probability of a particular genotype being formed by fertilization is equal to the product of the probabilities of forming each type of gamete needed to product that genotype

Multiplication Rule States:  The probability that 2 or more independent events will occur together in some specific combination can be determined by multiplying the probability of one event by the probability of another event ½ x ½ = ¼

Hardy-Weinberg Principle (1908) States:  Frequencies of alleles and genotypes in a population remain constant from generation to generation, provided that only Mendelian segregation and recombination of alleles are at work  Such a gene pool is called Hardy-Weinberg Equilibrium

Hardy-Weinberg Principle (1908) p = frequency of the dominant allele in the population q = frequency of the recessive allele in the population p 2 = percentage of the homozygous dominant individuals q 2 = percentage of the homozygous recessive individuals 2pq = percentage of heterozygous individuals

Hardy-Weinberg Principle

Pleiotropy  The ability of a single gene to effect other multiple genes  tryosine Chickens and the Frizzle Trait

Epistasis  The expression of a gene at one locus may affect the expression of another gene at another locus – called “modifier genes”  Will cause a variance in the F 2 ratio of 9:3:3:1 Chickens and the Frizzle Trait

Polygenic Traits  Called Quantitative Characters  Creates phenotypic gradiations  Hair color  Skin color  Height  Eye Color

Pedigrees – Humans follow Inheritance Patterns

Chapter 12 Chromosomal Basis for Inheritance