Mendelian Genetics Basics Fernando

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Mendelian Genetics Basics.
Smart board activity + Mendel´s laws + Genetics Basics Vocabulary.

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Mendelian Genetics Basics Fernando

  1. 1. Genetics basics Mendelian activity
  2. 2. Parent Generation
  3. 3. Parent Generation Cross pollination
  4. 4. Parent Generation ?
  5. 5. <ul><li>result </li></ul>
  6. 6. Parent Generation F1 Generation
  7. 8. Parent Generation F1 Generation
  8. 9. Parent Generation F1 Generation Self pollination
  9. 10. Parent Generation F1 Generation ?
  10. 11. <ul><li>result </li></ul>
  11. 12. Parent Generation F1 Generation F2 Generation, 3:1 ratio
  12. 13. Parent Generation F1 Generation F2 Generation, 3:1 ratio Why?
  13. 14. Parent Generation F1 Generation F2 Generation, 3:1 ratio Why?
  14. 15. What Do the Peas Look Like?
  15. 16. Mendelian vocabulary <ul><li>Hereditary factors </li></ul><ul><li>Hybrid </li></ul><ul><li>Pure or purebreed </li></ul>
  16. 17. Dihybrid Cross <ul><li>Traits : Seed shape & Seed color </li></ul><ul><li>Alleles : </li></ul><ul><li>R round / r wrinkled </li></ul><ul><li>Y yellow / y green </li></ul>RrYy x RrYy
  17. 18. RrYy x RrYy RY Ry rY ry RY Ry rY ry All possible gamete combinations
  18. 20. Genetic Terminology <ul><li>Trait - any characteristic that can be passed from parent to offspring </li></ul><ul><li>Heredity - passing of traits from parent to offspring </li></ul><ul><li>Genetics - study of heredity </li></ul>
  19. 21. Types of Genetic Crosses <ul><li>Monohybrid cross - cross involving a single trait e.g. flower color </li></ul><ul><li>Dihybrid cross - cross involving two traits e.g. flower color & plant height </li></ul>
  20. 22. <ul><li>Alleles - two forms of a gene (dominant & recessive) </li></ul><ul><li>Dominant - stronger of two genes expressed in the hybrid; represented by a capital letter (R) </li></ul><ul><li>Recessive - gene that shows up less often in a cross; represented by a lowercase letter (r) </li></ul>Terminology
  21. 23. <ul><li>Genotype - gene combination for a trait (e.g. RR, Rr, rr) </li></ul><ul><li>Phenotype - the physical feature resulting from a genotype (e.g. red, white) </li></ul>Terminology
  22. 24. Genotypes <ul><li>Homozygous genotype – When the two alleles are same (dominant or 2 recessive genes ) e.g. TT or tt; also called pure  </li></ul><ul><li>Heterozygous genotype – When the 2 alleles are different- one dominant & one recessive allele    ( e.g. Tt); also called hybrid </li></ul>
  23. 26. Mendel’s Laws 1. Law of Dominance 2. Law of Segregation 3. Law of Independent assortment
  24. 27. <ul><li>Law of Dominance </li></ul>States that on crossing homozygous organisms for single pair of contrasting characters, only one characters make its appearance in F 1 generation and is name as Dominant character . 1
  25. 29. Law of Segregation <ul><li>During the formation of gametes (eggs or sperm), the two alleles responsible for a trait separate from each other. </li></ul><ul><li>Alleles for a trait are then &quot;recombined&quot; at fertilization, producing the genotype for the traits of the offspring . </li></ul>2
  26. 31. Law of Independent Assortment <ul><li>Alleles for different traits are distributed to sex cells (& offspring) independently of one another. </li></ul><ul><li>This law can be illustrated using dihybrid crosses . </li></ul>3
  27. 35. Mendel´s pollination method
  28. 36. Mendel’s Experimental Methods <ul><li>Mendel hand-pollinated flowers using a paintbrush </li></ul><ul><ul><li>He could snip (cut) the stamens to prevent self-pollination </li></ul></ul><ul><li>He traced traits through the several generations </li></ul>
  29. 38. Why peas?
  30. 39. Why peas, Pisum sativum ? <ul><li>Can be grown in a small area </li></ul><ul><li>Produce lots of offspring </li></ul><ul><li>Produce pure plants when allowed to self-pollinate </li></ul><ul><li>several generations </li></ul><ul><li>Can be artificially cross-pollinated </li></ul><ul><li>Bisexual. </li></ul><ul><li>Many traits known . </li></ul><ul><li>Above all, easy to grow </li></ul>
  31. 40. <ul><li>Some slides were taken from a previous work </li></ul><ul><li>by Dr. R. Siva (VIT University, INDIA) </li></ul>

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