6 Mendel noticed plant height, flower position, pod color & appearance, seed color & appearance, and flower colorGametes = sex cellsFertilization = process of uniting female gamete & male gameteZygote = fertilized cellPollination = transfer of pollen from male reproductive organ to the female reproductive organ
8 Mendel’s Monohybrid Crosses Mendel crossed pea plants, testing one trait at a timeEx: Flower ColorMendel crossed a purebred purple flower pea with a purebred white flower peaHybrid = offspring of parents that have different forms of a traitPurebred = produces offspring w/ the same trait when self-fertilized
9 F1 generation = offspring of the parent generation, first generation P generation = parentsF1 generation = offspring of the parent generation, first generationF2 generation = offspring of a F1 mating with another F1, second generationCerval & Savannah cat
11 Dominant & RecessiveOffspring get two copies of genes for a trait (ONE FROM MOM, ONE FROM DAD), sometimes one copy dominates over the other copyTrait = variant of a certain characteristic based on geneticsGenes = found in chromosomes, made of DNA (they make you like you, they make peas look like peas!)Allele = alternative versions of a geneDominant = an allele that dominates over the recessive allele; only need one copy to be expressedRecessive = an allele that gets masked if a dominant is paired with it; must have two copies to be expressed
13 What happened to the white flowers in the F1 generation What happened to the white flowers in the F1 generation? Which color is the dominant color?
14 The recessive white color was “masked” in the F1 generation by the dominant purple color, but it reappeared again in the F2 generation
15 Each individual organism will have 2 alleles for a trait (remember, one from each parent) Homozygous = an organism with 2 identical alleles for a traitHeterozygous = an organism with 2 different alleles for a trait
16 Alleles for flower color are represented by letters: P = dominant allele for purple flowersp = recessive allele for white flowersBe careful, representations are case sensitive!!!Genotype = allele combinationPhenotype = the way an organism looks, trait that is expressed
17 What was the genotype of the purple flower from the P Generation? PPWhat was the genotype of the white flower from the P Generation?ppHow do we figure the probability of the genotypes of the F1 Generation?Monohybrid Cross (involves one trait)
20 Test Cross Used to determine an unknown dominant genotype. Cross the unknown with a homozygous recessive and look at the phenotype results.100% dominant means the genotype was homozygous dominant50% dominant : 50% recessive means the genotype was heterozygous
21 Mendel’s Law of Heredity Cont. Chapter 10, Section 1
22 Law of Segregation Each individual has 2 alleles for each gene During gamete (sex cell) production an individual separates its pairs of allelesEach gamete gets one allele !!!Alleles pair up again when one gamete joins with another gamete during fertilization
23 Law of Independent Assortment Genes for different traits are inherited independently of one anotherEx: Pea plants can be tall (T) or short (t) and they can also have purple flowers (P) or white flowers (p)Just because a pea plant has the dominant trait for height does not mean that it will have the dominant trait for flower color too
24 Dihybrid Crosses Round seeds (R), wrinkled seeds (r) Purple flowers (P), white flowers (p)An individual whose genotype is RRPP has what phenotype?Round seeds, purple flowersAn individual whose genotype is rrpp has what phenotype?Wrinkled seeds, white flowersAn individual whose genotype is RrPp has what phenotype?
25 2 characteristics per cross Punnett Square has 16 boxes
26 Method to organize alleles on a Punnett Square F firstO outterI innerL last
27 R= round r= wrinkledP= purple flowers p= white flowersPlease cross a homozygous round, heterozygous purple plant with a homozygous wrinkled, heterozygous purple plant.