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Genetics

Genetics. Chromosomes . Autosomes : chromosomes that do not contain genes that determine the sex of an individual Sex chromosomes : chromosomes that contain genes that determine the sex of an individual. Sex Determination.

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Genetics

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  1. Genetics

  2. Chromosomes • Autosomes: chromosomes that do not contain genes that determine the sex of an individual • Sexchromosomes: chromosomes that contain genes that determine the sex of an individual

  3. Sex Determination • Sex determination: one sex chromosome determines the sex of the organism • In humans eggs have an X chromosome and sperm have either an X or a Y chromosome

  4. Fruit Fly Karyotype

  5. Chicken Karyotype

  6. Dog Karyotype

  7. Chromosome mapping • Chromosomemapping: a diagram that shows where genes are located on each chromosome

  8. Genes • Gene: a section of DNA that codes information for making proteins. • Genes are located on Chromosomes

  9. Alleles • Allele- an alternative form of a gene • Represented by letters of the alphabet • Dominant-masks the other traits • Capital letters • Recessive-hidden by dominant trait • Lower case letters

  10. Traits • Trait: a characteristic that is determined by what genes an organism has

  11. Traits and Heredity • Dominanttrait: masks the other traits • Capital letters • Recessivetrait: hidden by dominant trait • Lower case letters • Homozygous: has 2 of the same allele for a gene (AA or aa) • Heterozygous: has 2 different alleles for the same gene (Aa)

  12. Heredity • Heredity: the passing of traits from parent to offspring

  13. Traits and Heredity • Genotype: an organisms genetic makeup (alleles that are on our chromosomes) • Phenotype: an organisms appearance (traits that are expressed)

  14. Gregor Mendel • The father of genetics • Austrian monk who worked on genetics with pea plants

  15. Mendel’s Laws • 1. The Law of Segregation: during the formation of gametes (sperm and egg) the two copies of each hereditary factor separate so that offspring acquire one factor from each parent • 2. The Law of Independent Assortment: the hereditary factors separate randomly during the formation of gametes • 3. The Law of Dominance: one factor in a pair of traits dominates the other in inheritance

  16. Vocabulary • True-breeding: pure, always produces offspring with the same traits • Self-pollination: sperm pollinates egg in the same plants • Cross-pollination: sperm pollinates egg in a different plant

  17. Vocabulary HybridCross: Cross between parents with one differing trait P or P₁: Parental Generation F₁: First Generation offspring F₂: Second Generation offspring

  18. Mendel’s Experiments

  19. Punnett Squares • PunnettSquare: predicts the genetic probabilities of offspring

  20. Punnett Squares

  21. Punnett Squares

  22. Dihybrid crosses • Dihybridcross: 2 traits are tracked because the genes move together R: round r: winkled Y: yellow y: green

  23. Dihybrid crosses

  24. Other forms of inheritance • IncompleteDominance: neither allele is completely dominant over the other

  25. Other forms of Inheritance • Co-dominance: both alleles are expressed

  26. Sex-linked Traits • Sex-linked: determined by the x chromosome • Males will be affected more than females because males only have one X chromosome

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