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GENETICS

GENETICS. What is it?. Genetics Terms Trait: Physical characteristics ex. Hair color or eye color Allele: Different forms of a trait (letters that code for a trait) ex. TT (tall) or tt (short) Purebred : only producing or carrying one type of gene or allele.

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GENETICS

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  1. GENETICS What is it?

  2. Genetics Terms Trait: Physical characteristics ex. Hair color or eye color Allele: Different forms of a trait (letters that code for a trait) ex. TT (tall) or tt (short) Purebred: only producing or carrying one type of gene or allele. ex: TT, WW, (all dominant) tt, ww (all recessive)

  3. Genetics Terms Hybrid: Having two different forms of a single trait. ex. Tt ( T= tall, and t= short) Phenotype: Physical representation of a trait. ex: brown eyes, black hair. Genotype: The set of genes that an organism has. ex: TT, Tt, tt, WW, Ww, ww Sexual Reproduction: reproduction involving 2 organisms. Asexual Reproduction: reproduction involving only one organism.

  4. Gregor Mendel • Austrian monk • Studied garden peas from 1856-63 • Known as the father of genetics • His experiments were special because: • They were quantitative (measurable) • 2)He discovered that traits were passed from parent to offspring.

  5. Mendelian Genetics Gamete -- reproductive cell (seed and pollen) Zygote-- fertilized egg cell In Mendel’s experiments, which plants were homo or heterozygous inP0? F1? F2? F3? Genotype-- genetic makeup of an organism (what alleles it contains) Phenotype-- observable properties of an organism

  6. Mendelian Genetics F0 generation-- originally crossed organisms (parents) (cross pollination) F1 generation-- offspring of the F0 generation F2 generation-- offspring of F1 generation (self pollination) dominant– trait which is always expressed recessive– trait which is only expressed when the dominant trait is not present.

  7. Pea Plant Traits

  8. Pea Plant Traits

  9. Mendelian Genetics Allele-- particular form of a gene homozygous-- organism carrying two copies of the same allele heterozygous- organism carrying different alleles of the same gene In Mendel’s experiments, which plants were homozygous or heterozygous in P0? F1? F2? F3?

  10. Mendel’s Experiment

  11. 75% 25% Punnett square representing possible genotypes and phenotypes and their proportions in the F2 and F3 generations.

  12. Punnett square representing possible genotypes and phenotypes and their proportions in the F2 generation.

  13. Mendelian Genetics Classical Punett's Square is a way to determine ways traits can be passed . This is another way of determining the probability that a trait will show up. F1 cross F0 cross backcross: mating F1 generation to the parental (usually recessive) strain

  14. Genetic Crosses • Tall is dominant and short is recessive in pea plant height. Cross a homozygous tall pea plant with a short pea plant. Provide both genotypic and phenotypic ratios. • Brown is dominant and white is recessive in guinea pig hair color. Cross two hybrid brown guinea pigs. Provide both genotypic and phenotypic ratios. • Green is dominant and yellow is recessive in pea plant color. Cross a hybrid green plant with a yellow plant. Provide both genotypic and phenotypic ratios. • Purple is dominant and white is recessive in pea plant flower color. Cross a homozygous purple flowered plant with a white plant. Provide both ratios.

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