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Genetics

Genetics. Heredity. Lesson 1. Do Now. Video: What are genes ?. Heredity. The passage of these coded instructions from one generation to the next Some traits are readily observable – ex: hair color, leaf shape, shape of wing.. Etc.

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Genetics

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  1. Genetics

  2. Heredity Lesson 1

  3. Do Now Video: What are genes?

  4. Heredity The passage of these coded instructions from one generation to the next Some traits are readily observable – ex: hair color, leaf shape, shape of wing.. Etc. ** others are less obvious ex: defective heart, sickle cell anemia, color blindness

  5. Inheritance of chromosomes • Egg + sperm  zygote egg meiosis zygote mitosis &development fertilization sperm

  6. Inheritance of genes • On the chromosomes passed from Mom & Dad to offspring are genes • may be same information • may be different information eye color (blue or brown?) eye color (blue or brown?)

  7. Effect of genes • Genes come in different versions • brown vs. blue eyes • brown vs. blonde hair • alleles

  8. Genes affect what you look like X bb BB Bb Bb Bb Bb Where did the blue eyes go??

  9. Genes affect what you look like… X bb Bb Bb Bb bb bb Why did the blue eyes stay??

  10. Genes affect what you look like… X Bb Bb bb BB or Bb BB or Bb BB or Bb Where did the blue eyes come from??

  11. What did we show here? • Genes come in “versions” • brown vs. blue eye color • alleles • Alleles are inherited separately from each parent • brown & blue eye colors are separate & do not blend • either havebrown or blue eyes, not a blend • Some alleles mask others • brown eye color masked blue

  12. eye color (blue?) hair color hair color How does this work? • Paired chromosomes have same kind of genes • but may be different alleles eye color (brown?)

  13. In Class Assignment • Hereditary Simulation Worksheet • Determining your genes worksheet

  14. Homework • History and Terminology worksheet

  15. Punnett Crosses • Lesson 2

  16. Do Now Take out Homework from last night & begin looking over the questions for the video Where do your genes come from?

  17. Traits are inherited as separate units • For each trait, an organism inherits 2 copies of a gene, 1 from each parent • a diploid organism inherits 1 set of chromosomes from each parent • diploid = 2 sets of chromosomes 1 from Mom homologous chromosomes 1 from Dad

  18. Making gametes B B B b b b BB Bb bb BB = brown eyes bb= blues eyes Bb= brown eyes  brown is dominant over blue  blue is recessive to brown Remember meiosis!

  19. B B B b b b BB Bb bb How do we say it? 2 of the same Homozygous BB = brown eyes bb= blues eyes homozygous dominant homozygous recessive 2 different Heterozygous Bb= brown eyes

  20. B b B b Punnett squares Bb x Bb male / sperm X BB Bb female / eggs Bb bb

  21. Genetics vs. appearance • There can be a difference between how an organism looks & its genetics • appearance or trait = phenotype • brown eyes vs. blue eyes • genetic makeup = genotype • BB, Bb, bb 2 people can have the same appearance but have different genetics: BB vs Bb

  22. B B B b BB Bb Genetics vs. appearance How were these brown eyes made? eye color (brown) eye color (brown) eye color (brown) eye color (blue) vs.

  23. In class assignment • Genetics Practice 1: Basic genetics

  24. Homework • Basics Punnett Squares

  25. Penny Genetics Lesson 3 Lab Activity

  26. Genetics&The Work of Mendel Lesson 4 2007-2008

  27. Do Now • BrainPop: heredity

  28. Gregor MendelThe Founder of Genetics An Austrian monk who lived over 100 years ago and studied how traits were passed from 1 generation to the next He did hundreds of experiments on thousands of pea plants in the monastery and used mathematical analysis to explain who heredity worked

  29. Modern genetics began in the mid-1800s in an abbey garden, where a monk named Gregor Mendel documented inheritance in peas used good experimental design usedmathematicalanalysis collected data & counted them excellent example of scientific method Gregor Mendel

  30. Mendel’s work Bred pea plants cross-pollinate true breeding parents raised seed & then observed traits allowed offspring to self-pollinate& observed next generation Pollen transferred from white flower to stigma of purple flower all purple flowers result self-pollinate ?

  31. Mendel collected data for 7 pea traits

  32. Looking closer at Mendel’s work true-breeding purple-flower peas true-breeding white-flower peas 100% purple-flower peas 1st generation (hybrids) 100% 75% purple-flower peas 25% white-flower peas 3:1 2nd generation X Parents self-pollinate

  33. What did Mendel’s findings mean? Some traits mask others purple & white flower colors are separate traits that do not blend purple x white ≠ light purple purplemaskedwhite dominant allele functional protein affects characteristic masks other alleles recessive allele no noticeable effect allele makes a non-functioning protein I’ll speak for both of us! allele producingfunctional protein mutant allele malfunctioningprotein homologouschromosomes

  34. Genotype vs. phenotype Difference between how an organism “looks” & its genetics phenotype description of an organism’s trait genotype description of an organism’s genetic makeup X P purple white F1 all purple Explain Mendel’s results using …dominant&recessive …phenotype&genotype

  35. Making crosses Can represent alleles as letters flower color alleles  P or p true-breeding purple-flower peas  PP true-breeding white-flower peas  pp PP pp x X P purple white F1 all purple Pp

  36. Punnett squares Pp x Pp PP 25% male / sperm P p Pp 50% 75% P Pp female / eggs pp p 25% 25% Aaaaah, phenotype & genotypecan have different ratios 1st generation (hybrids) % genotype % phenotype PP Pp Pp pp 1:2:1 3:1

  37. Law of Segregation • Two alleles in an individual will separate during gamete formation and act independently.

  38. Law of Independent Assortment • Describes the relation between different genes. • Ex. Plant Height and Color, if on different chromosomes can act independently during test crosses

  39. Law of Independent Assortment

  40. Linkage • Alleles fail to assort independently because they are on the same chromosome • Recombination affects Linkage - The further apart the genes the more recombination

  41. Linked Genes On the same chromosome = inherited together ex: red hair/freckles (crossing over can “unlink” genes) Karyotype = photograph of chromosomes with camera attached to a microscope  paired up and # from largest to smallest Human karyotype = 22 pairs of perfectly matched chromosomes (autosomes) 1 pair of sex chromosomes XY (male) or XX (female)

  42. Egg cells always have 22 autosomes + X Sperm cells always have 22 autosomes + X or Y  sperm cells determines the sex of the organism Probability of having a boy or girl in pregnancy: 50% chance boy 50% chance girl

  43. Inheritance Patterns • Pedigrees – family tree depicting inheritance of a particular trait over several generations • Males are indicated by squares, females by circles • Individuals affected by trait are shaded while those unaffected are unshaded • Carriers of the trait are half shaded

  44. Pedigree

  45. In class assignment • Simple Genetics Practice Problems

  46. Homework • Complete simple genetics practice for homework

  47. Gene Expression • Lesson 5

  48. Do Now • Directed Reading Activity: Gene Expression

  49. Phenotype is controlled by both environment & genes Environment effect on genes Human skin color is influenced by both genetics & environmental conditions Coat color in arctic fox influenced by heat sensitive alleles Color of Hydrangea flowers is influenced by soil pH

  50. In class assignment • Gene Expression

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