Gregor Mendel & Genetics Principles of Science Mr. Porter
Gregor Mendel: The Father of Genetics Gregor Mendel - a 19th century monk from eastern Europe, was the first to study how traits are passed.
Genetics Heredity - the passing of traits from parents to offspring. Genetics -the study of heredity.
Genetics: Mendel s Experiment Mendel chose peas because peas are easy to breed for pure traits. Purebred - an organism that always produces the same traits in its offspring. Mendel studied 7 purebred traits for peas.
Trait Dominant Recessive Genetics: Mendel s Studies Seed Shape Smooth shape Wrinkled shape Seed Color Yellow Green Flower Color Red White Flower Position Axial Terminal Stem Length Long stem Short stem Pod Shape Inflated (smooth) Connected (bumped) Pod Color Green Yellow
Genetics Alleles - different forms of a gene for a trait. Examples: Gene Eye Color Hair Type Height Disease Allele Blue eyes / Brown eyes Straight hair / Curly hair Tall / Short Low risk / High risk for high BP
Genetics: Traits Dominant trait - a trait that is expressed when there is one of each type of allele. Recessive trait - a trait that is hidden when there is one of each kind of allele.
Trait Dominant Recessive Genetics: Mendel s Studies Seed Shape Smooth shape Wrinkled shape Seed Color Yellow Green Flower Color Red White Flower Position Axial Terminal Stem Length Long stem Short stem Pod Shape Inflated (smooth) Connected (bumped) Pod Color Green Yellow
Genetics: Punnett Square Genotype - shows the genetic make-up of an organism or trait. Represented by pairs of alleles for a "trait. Dominant - Capital letter Example: T = long stem Recessive - Lower case letter Example: t = short stem
Genetics: Punnett Square Homozygous Gene with two of the same alleles Example: TT or tt Heterozygous - Gene with two different alleles Example: Tt Phenotype - The physical trait that shows as a result of a genotype.
Genetics: Punnett Square Trait Genotype Phenotype Stem Size TT Long Stem Stem Size Tt Long Stem Stem Size tt Short Stem Cross-pollination - taking pollen from the male reproductive organ of one plant s flower and placing them on the female reproductive organ of another plant s flower.
Mendel s Experiment 1) Mendel cross-bred a purebred tall plant with a pure-bred short plant 2) The results (F1, first generation) were all tall. 3) The short trait seemed to disappear
Mendel s Experiment 4) He then allowed the tall plants to cross-pollinate and planted the seeds. 5) To his surprise, the short form reappeared with the tall form in this second (F2) generation.
Punnett Square: Stem Size - F 1 Tt Tt Tt Tt
Punnett Square: Stem Size - F 2 TT Tt Tt tt
Punnett Square Practice Two brown-eyed parents have a child. Dad is a purebred for brown eye color Mom is heterozygous for brown eye color Set up a Punnett Square that determines the probability for the outcome for the eye color of their offspring B = Dominant (Brown eyes) b = Recessive (Blue eyes)
Punnett Square Practice
Punnett Square Practice Dad is a purebred for blue eye color Mom is heterozygous for brown eye color Set up a Punnett Square that determines the probability for the outcome for the eye color of their offspring B = Dominant (Brown eyes) b = Recessive (Blue eyes)
Punnett Square Practice
Review 1. What is heredity? 2. Who is considered the father of modern genetics? 3. What is the difference between dominant and recessive genes? 4. What are alleles? 5. Were there any short stem plants in the F1 generation? Why? 6. Were there any short stem plants in the F2 generation? Why?
Heredity & Environment The environment can even play a role in which traits survive for a species. Nature vs. Nurture
Heredity & Environment
Heredity & Environment
Heredity & Environment Genetic Variation - the differences in heredity between individuals of a species. Mutation - Changes in a gene. X-rays, UV rays, some chemicals, and other factors can cause mutations. 99.9% of mutations are harmful to the organisms
Albinism
Review 1. What is the difference between a mutation and genetic variation? 2. What factors can affect the genes that an organism will successfully carry?