1 / 51

Genetics

Genetics. Genetics. What is Genetics ?. Genetics is the study of heredity and variation Examples of genetic variation. 1. Domesticated species 2. Human genetics 3. Natural Populations. History of Genetics. Domestication of animals Cultivation of plants. Cultivated varieties.

harding-potter
Download Presentation

Genetics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Genetics Genetics

  2. What is Genetics ? Genetics is the study of heredity and variation Examples of genetic variation • 1. Domesticated species • 2. Human genetics • 3. Natural Populations

  3. History of Genetics • Domestication of animals • Cultivation of plants

  4. Cultivated varieties

  5. Animal Breeds

  6. Human Genetic Variation

  7. Variance

  8. Which suspect matches the blood stain ? Bloodstain

  9. Ethical Issues Boot GM out of animal feed

  10. Cloning

  11. American Journal of Medical Genetics Clinical Genetics Developmental Genetics Human Molecular Genetics Genetics European J. of Human Genetics Genetics Selection Evolution Nature Genetics Genetika Fungal Genetics and Biology Genome Cancer Genetics and Cytogenetics Genomics American J. Human Genetics Hereditas Opthalmic Genetics Japanese Journal of Human Genetics Human Genetics Journal of Heredity Current Genetics Molecular Biology and Evolution Animal Genetics Molecular Ecology Brazilian J. Genetics Molecular and General Genetics Biochemical Genetics Theoretical and Applied Genetics J. of Medical Genetics Trends in Genetics Genetic Journals

  12. Basic Concepts of Genetics Nucleus - contains genetic material DNA - genetic material 4 bases (nucleotides G, C, A, T) Gene - functional unit of heredity sequence of 4 nucleotides Chromosome -linear DNA molecule

  13. Basic Concepts of Genetics Cell/nuclear division • Mitosis (somatic tissue): identical cells • Meiosis (germ tissue): gametes

  14. Basic Concepts of Genetics • Mendelian Genetics (transmission genetics) • Molecular Genetics (hereditary material)

  15. Historical Notes 1865 Gregor Mendel - controlled genetic experiments (garden peas) - statistical regularity - theory of inheritance

  16. Understanding Genetics • Relationship between: GENOTYPE ENVIRONMENT PHENOTYPE set of genes morphology inherited physiology behaviour

  17. Mendelian Genetics Requirements: 1. Attributes of the phenotype that vary among individuals 2. Phenotypic variation caused by genetic differences

  18. Genotype and Phenotype • The genotype is our actual genes. We cannot see our genes. • The phenotype is the physical expression of those genes.

  19. Mendelian Genetics • Genes - cannot be observed directly • Phenotypes - observed directly ** inheritance of phenotypes used to infer the inheritance of genes

  20. Mendel’s Experiments Seven Pea varieties “True Breeding Lines” Character “traits”Phenotypes 1. seed shape round, wrinkled 2. seed colour yellow, green 3. flowers (pods) axial, terminal 4. pods full, constricted 5. pods yellow, green 6. flowers violet, white 7. stem tall, dwarf

  21. Fertilization Gametes carry the genetic information about an organism. The male gamete produce Sperm. The female gametes produce Eggs. The process in which one gamete is united with another is called Fertilization.

  22. Fertilization Daddy Mommy BABY

  23. Self-Fertilization • When an organism has both male and female gametes, they are able to self-fertilize.

  24. Advantages • easy to grow • matures in a season • self-fertilizing • easy to cross-fertilize

  25. Dominance • Some characteristics overshadow others when crossed. • This is referred to as a Dominant trait. • The unseen trait is said to be Recessive. • Dominant traits are represented on charts by a capital letter. • Recessive traits are represented by a lower case letter

  26. Pure Lines(Homozygous) • When an organism is said to be of pure lines, it means their genotype is two identical alleles. • TT is the pure line for a tall plant. • tt is the pure line for a short plant.

  27. Hybrids(Heterozygous) • When parents of two different pure lines are crossed, the offspring are called hybrids. • A hybrid’s genotype consists of two different alleles. • The genotype Tt would be a tall plant hybrid.

  28. Homozygous and Heterozygous • When an organism has identical alleles, it is said to be homozygous. • TT, and tt would both be homozygous • When an organism has two different alleles, it is heterozygous. • Tt is heterozygous.

  29. Punnett Square T T T TT TT T TT TT

  30. Cross Pollination

  31. Punnett Square of Cross Pollination MOM T t DAD T Tt TT T TT Tt

  32. Punnett Square (Monohybrid Cross) MOM T t DAD T Tt TT t Tt tt

  33. Punnett Square MOM T t DAD t tt Tt t Tt tt

  34. Punnett Square MOM t t DAD t tt tt t tt tt

  35. Mendel’s Experimental Approach Suitable experimental organism • examine few traits in each experiment • accurate quantitative records • analyzed data formulated hypotheses

  36. Genetic Analysis (pea shape)

  37. Hypothesis to explain results 1. Hereditary determinants (genes) 2. Each adult plant has a gene pair F1 plants: one gene dominant phenotype one gene recessive phenotype

  38. Hypothesis (continued) 3. Members of a gene pair segregate equally into the gametes 4. Each gamete has only one member of a gene pair 5. Gametes combine at random to form zygote

  39. Hypothesis

  40. Self Fertilization

  41. Test of Equal Segregation Hypothesis

  42. Principle of Segregation Three parts: 1. Hereditary characteristics are determined by distinct units or factors. 2. For each characteristic, an individual carries two factors, one inherited from each parent. 3. The two factors of each pair segregate from each other and end up in separate gametes.

  43. If a plant is short, what is its genotype? • It must be homozygous recessive, tt.

  44. If a plant is tall, what is its genotype? • It could be homozygous dominant, or heterozygous. TT, or Tt. • To determine which genotype it is we use a test cross.

  45. Test Cross Heterozygous Known homozygous recessive T t 1/2 Tall 1/2 Short t tt Tt t Tt tt

  46. Test Cross Homozygous Known homozygous recessive T T All Tall N0 Short t Tt Tt t Tt Tt

  47. Genetic Terminology Genes: hereditary elements • Alleles: forms of a gene: A a • Heterozygote: Aa • Homozygotes: AA aa • Genotype: Genetic makeup • Phenotype: What we actually see • Dominance AA, Aa same phenotype

  48. Summary Experimental: 1. Two pure breeding lines 2. Cross --------> F1 hybrid 3. Self F1 ------> F2

  49. Summary Results: 1. F1 one phenotype 2. F2 3:1 ratio of 2 phenotypes

More Related