6 Mendel’s Experimental Design Mendel raised pea plants to “breed true,” I.e. tall only produced tall, short only produced short
7 Mendel’s Experimental Design Mendel raised pea plants to “breed true,” I.e. tall only produced tall, short only produced shortMendel crossed one true-breeding variety with the alternate true-breeding variety, e.g. tall x short
10 P1 Tall X ShortF1 All TallF2 3/4 Tall 1/4 Short
11 Mendel HypothesizedThat something was passed from parents to offspring to determine height; he called this an allele
12 P1 Tall X ShortT tF1 All TallTF2 3/4 Tall 1/4 Short
13 Mendel HypothesizedThat something was passed from parents to offspring to determine height; he called this an alleleFurther, since the t allele was “hidden” in the F1, but reappeared in the F2, plants must have a pair of alleles for each trait.
14 P1 Tall X ShortTT ttF1 All TallTtF2 3/4 Tall 1/4 ShortT? tt
15 When an organism had a pair of alleles the same, e. g When an organism had a pair of alleles the same, e.g. TT or tt, he called this homozygousWhen an organism had an unlike pair of alleles, e.g. Tt, he called this heterozygousThese terms refer to an organism’s genotypeThe appearance of the organism he called it’s phenotype
16 Practice Vocab Ex. Plant Height Genotype Phenotype Pure or Hybrid Homozygous/Heterozygous
17 More practice Ex. Flower color Genotype Phenotype Pure or Hybrid Homozygous/Heterozygous
18 Mendel proposed several principles regarding his findings If an organism is heterozygous and only one phenotype appears, this is the dominant phenotype, the alternate is the recessive phenotypeWhen an organism reproduces, allele pairs must segregate and only one member of each allele pair is passed along to the next generation.
19 Solving Genetic Problems T Tt ttTTtT X t = T tF1
23 Test Cross What is the genotype of a short pea plant?______ What is the genotype of a tall pea plant?_____ or _____Mendel developed a way of testing whether the tall plant is homozygous or heterozygous. It was the test cross
25 Independent Assortment The inheritance of any characteristic is independent of the inheritance of any other characteristic.Ex. The inheritance of height is independent from pea color.Mendel provided evidence for this through dihybrid crosses.
26 Dihybrid Cross TtPp X TtPp To solve this problem you can use a 16 block punnett square or the Forkline method.
32 Inheritance patterns that Mendel did not know about Incomplete dominanceCodominanceMultiple allelesPolygenic InheritenceSex Linkage
33 Incomplete DominanceIncomplete dominance does not involve an allele that masks recessive allele. Instead there is a blending of the two alleles.Ex. Red flower X White flower =PinkCross Two Pink flowering plants
34 ExampleCross a two pink flowering plantsRW X RW
35 CodominanceCodominance does not involve an allele that masks recessive allele. Instead both alleles show in the phenotypeEx. Brown horse X White horse =SpottedCross a brown horse with a spotted horse
36 Codominance ExmpleCross a brown horse with a spotted horse.BB X BW
37 Multiple AllelesSome phenotypes can be determined by more than two alleles.Ex. ABO Blood typeGenotypes PhenotypesAA A Blood TypeAO A Blood TypeBB B Blood TypeBO B Blood TypeOO O Blood TypeAB AB Blood Type
38 Blood Type ProblemsCross a heterozygous A blood type with a heterozygous B blood typeiAiO X iBiO
39 Polygenic Inheritance The inheritance of some characteristics are determined by more than two alleles.Ex. Skin color, eye color, height, and noses. Phenotypes of polygenic inheritance are a result of the blending of many genes.
40 Sex Linkage Who determines the sex of the baby? How would a gene found on the X chromosome be inherited and expressed differently in males vs. females?