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Heredity and Genetics

Heredity and Genetics. What makes you, you?. Learned vs. Inherited. Learned behaviors. Table manners How to throw a ball. Inherited . Eye color Curly hair Height. Heredity. The passing of traits from parents to offspring. Characteristics vs. Traits.

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Heredity and Genetics

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  1. Heredity and Genetics

  2. What makes you, you?

  3. Learned vs. Inherited

  4. Learned behaviors • Table manners • How to throw a ball

  5. Inherited Eye color Curly hair Height

  6. Heredity The passing of traits from parents to offspring.

  7. Characteristics vs. Traits • Characteristic- a feature that has different forms in a population • Such as hair color (general) • Trait- different forms of the characteristics • Such as black hair (specific)

  8. History of Genetics • Gregor Mendel- the father of modern genetics • Studied pea plants • Why? • Fast growing • Able to cross pollinate and self-pollinate

  9. Vocabulary Cross pollination: pollen from one plant fertilizes another plant. Self-pollination: pollen from flower fertilizes itself True-breeding plant: a plant, that when it self pollinates, its offspring will have the same traits. “Pure” Hybrid: an offspring of two different parents

  10. Mendel’s First Experiment Mendel crossed (cross pollinated) true-breeding purple flowered pea plant with a true-breeding white pea plant. The offspring are called first generation (F1).

  11. All of the pea plants in the first generation had purple flowers.

  12. Mendel got similar results each time, one trait was always present in the first generation and the other trait seemed to disappear. Mendel called the trait that appeared the Dominate Trait. (shown as a capital letter) The trait that does not express itself is called the Recessive Trait. (shown as a lower case letter)

  13. Mendel’s Second Experiment Mendel then allowed the F1 generation plants to self-pollinate, producing an F2 generation. Some of the F2 generation plants were white.

  14. Mendel noticed that the ratio of dominant (purple) plants to recessive (white) plants was 3:1 His results could only be explained if each plant had 2 sets of instructions, one from each parent.

  15. Each parent gives a set of instructions called alleles. Two alleles make up a genotype (gene). Alleles are shown with either a capital letter (dominant) or a lower case letter (recessive).

  16. Example B b Bb allele allele genotype

  17. Vocabulary Genotype: both inherited alleles (Hh, AA, ff). Homozygous: gene with two dominant or two recessive alleles (BB, dd). True-breeding. Heterozygous: gene with one dominant and one recessive allele (Gg, pP). Hybrid. Phenotype: the outward expression of the genotype. What the genotype would look like, example: red hair.

  18. Punnett Squares a diagram that is used to predict the probability that a given trait will be expressed.

  19. Mendel’s ExperimentP=purple p=white PPxpp

  20. P=purplep=white PpxPp

  21. What needs to happen for a recessive trait to appear? • The genotype has to be homozygous recessive. • Two lower case letters

  22. Incomplete Dominance • Both alleles are expressed, resulting in a combined phenotype • Example: R = red W = white RR x WW

  23. Incomplete Dominance

  24. Sex Chromosomes • Males • XY • Females • XX

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