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Some individuals are able to bend their thumb back at the distal joint at 50° or more

Human Heredity. Some individuals are able to bend their thumb back at the distal joint at 50° or more. PTC Taster. The ability to detect a specific taste from the chemical phenylthiocarbamide (PTC) has been labeled as the trait PTC Tasting or Taster ..

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Some individuals are able to bend their thumb back at the distal joint at 50° or more

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  1. Human Heredity Some individuals are able to bend their thumb back at the distal joint at 50° or more

  2. PTC Taster • The ability to detect a specific taste from the chemical phenylthiocarbamide (PTC) has been labeled as the trait PTC Tasting or Taster.. • The gene for this trait has been mapped to the long arm of chromosome 7.

  3. Individual Phenotypes

  4. Class Phenotypes

  5. How do the class data compare to the actual answers? Bent Pinky Straight Dominant Roller Dominant Non-roller Thumb Bent Dominant Straight Free Dominant Attached Taster Dominant non

  6. Heredity DNA- deoxyribonucleic acid, stores genetic information Gene- a segment of DNA that codes for a trait NOVA Online | Cracking the Code of Life | 9 min, 6 min

  7. Heredity Chromosome- rod-shaped body, found in the nucleus, made of the DNA molecule Chromatin- loosely stored, relaxed DNA 25 to 30 THOUSAND genes at “rest” Mendel’s “factors” Are Chromosomes! video clip

  8. Karyotyping • In your lab tutorial, you looked at three patients who needed diagnosis. For all three patients, what was the trouble? • Specifically A? B? C? Last name lineup, check in Lab Notes

  9. Genetics- field of biology, study of heredity Heredity- how characteristics are passed from parent to offspring These black Labrador puppies are purebred—their parents and grandparents were black Labs with very similar genetic makeups.

  10. Their behavior and appearance is more varied as a result of their diverse genetic inheritance • The parents of these puppies were a mixture of different breeds

  11. Gregor Mendel FLOWER COLOR Purple White • WHO WAS HE? • Father of Genetics • Monk who lived in mid-1800s • worked with pea plants and researched heredity FLOWER POSITION Axial Terminal SEED COLOR Yellow Green SEED SHAPE Round Wrinkled Mendel observed 7 different plants characteristics of peas. These characteristics were called traits… POD SHAPE Inflated Constricted POD COLOR Green Yellow STEM LENGTH Figure 9.2A, B Tall Dwarf

  12. G. Mendel FLOWER COLOR Purple White • Three Key CHOICES- • Control over the breedings • Use of purebred plants for Parent Gen. • Written observations of “either-or” traits FLOWER POSITION Axial Terminal SEED COLOR Yellow Green SEED SHAPE Round Wrinkled POD SHAPE Inflated Constricted POD COLOR Green Yellow STEM LENGTH Figure 9.2A, B Tall Dwarf

  13. What are each of the traits shown in the pairs below? Mendel Cont. Flower Color • Peas are great to study because • Only two possible characteristics per trait • they easily cross-pollinate • and have many offspring! • Trait- a category that has two or more contrasting characteristics • Ex- seed color Flower Position Seed Color Seed Shape Pod Shape Pod Color Stem Length

  14. Mendel’s Experiments • In Mendel’s plant experiments, he used special names to describe each generation of pea plants • P1 generation- parent generation • F1 generation- offspring of parent generation • F2 generation- offspring of F1 generation Mendel and his Experiments- Video

  15. RESULTS White 1 Removed stamensfrom purple flower Dominant- (capital) a trait that covers another Recessive- (lower-case letter) trait that is hidden by a dominant gene Stamens Carpel 2 Transferred pollen from stamens of white flower to carpel of purple flower PARENTS(P) Purple 3 Pollinated carpel matured into pod 4 Planted seeds from pod OFF-SPRING(F1)

  16. Survey 5 people (including yourself)Based on your data, is a Widow’s peak dominant or recessive?

  17. What is your genotype?(Hint: assign letters for Widow’s peak and no Widow’s peak)

  18. Alleles • different forms of a gene that code for a trait • reside at the same place on homologous chromosomes Example- Bb GENE DOMINANT allele P a B P= purple p = white A = axial a= terminal B= buds b= no buds P a b RECESSIVE allele GENOTYPE: PP aa Bb HOMOZYGOUSfor thedominant allele HOMOZYGOUSfor therecessive allele HETEROZYGOUS Figure 9.4 Mendel’s Laws, Genotype vs. Phenotype- Video

  19. Genotype- genetic makeup of an organism (alleles) Example- PP Phenotype – physical appearance of an organism Example- purple colored petals gene P a B P= purple p = white A = axial a= terminal B= buds b= no buds P a b RECESSIVE allele GENOTYPE: PP aa Bb HOMOZYGOUSfor thedominant allele HOMOZYGOUSfor therecessive allele HETEROZYGOUS Figure 9.4

  20. For those with a widow’s Why is your genotype W?

  21. Homozygous= Purebred = having two copies of the same allele; BB or bb Heterozygous= Hybrid = two different alleles; Bb gene P a B P= purple p = white A = axial a= terminal B= buds b= no buds P a b RECESSIVE allele GENOTYPE: PP aa Bb HOMOZYGOUSfor thedominant allele HOMOZYGOUSfor therecessive allele HETEROZYGOUS Figure 9.4

  22. Review Question What is the difference between genes and alleles? Example: Blood type is the gene, what would the alleles be? Pg.205

  23. Should this Dog be named Spot? L t H A What is his GENOtype? What is his PHENOtype? What trait is he Homozygous for? l T H a

  24. Mendel: Law of Segregation From his pea experiments, Mendel believed: • Each individual inherits 2 copies of every gene. • During the formation of gametes, the 2 copies of a gene separate “segregate” (1 copy in every gamete). Parent 1 Parent 2 What happens when the F1s cross?

  25. Law of Segregation Cont.

  26. MONOHYBRID CROSSES • Monohybrid Cross- involves one pair of contrasting traits • Example- Cross a male and female, determine the gender of offspring • Punnett Square- Who? R.C.Punnett, geneticist What? tool used to predict the outcomes of crosses

  27. Punnett squares Who? P.183 • The Punnett square: grid system for predicting all possible genotypes from a mating (cross). • axis- each parent possible gametes • inside grid possible offspring genotypes • Punnett square yields ratio of potential genotypes and phenotypes.

  28. Law of Independent Assortment- Factors for different characteristics are distributed to gametes independently

  29. A dihybrid cross involves two traits. • Mendel’s dihybrid crosses led to his second law,the law of independent assortment. • The law of independent assortment states that allele pairs separate independently of each other during meiosis. • Mendel’s dihybrid crosses with heterozygous plants yielded a 9:3:3:1 phenotypic ratio.

  30. Dragon Lab

  31. Genetics and Probability • Probability- the likelihood that a specific outcome will occur • Expressed as: a fraction, decimal ratio, or % • In a basic Punnett Square, you have four 4 boxes so your ratios could be 1:4 (25%) , 2:4(50%) , 3:4(75%) , 4:4 (100%) Mendel’s works : 126 red: 122 white 126/248 = 50.8 % P(red)

  32. Your Notes look like this… EACH WILL BE A SEPARATE EXAMPLE Punnett Squares

  33. Example 1: Homozygous x Homozygous Homozygous for purple PP = purpleHomozygous for white pp = white Genotypic Ratio: Phenotypic Ratio:

  34. Example 2: Homozygous x Heterozygous Homozygous for black coat BB Heterozygous for black coat Bb Genotypic Ratio: Phenotypic Ratio:

  35. Example 3: Heterozygous x Heterozygous Heterozygous for black coat BbHeterozygous for black coat Bb Genotypic Ratio: Phenotypic Ratio:

  36. Example 4: Testcross-individual of unknown genotype is crossed with a homozygous recessive individual UNKNOWN! Is he BB or Bb? Genotypic Ratio: Phenotypic Ratio: Homozygous Recessive

  37. TEST CROSS Results tell whether tested individual is PUREBRED or HYBRID dominant. ---Test Cross Ex. Would give 100% Dominant offspring if the individual was PURE for the dominant trait. ---ANY recessive phenotype offspring mean the tested parent must have been HETEROZYGOUS

  38. Test Cross example 2 P1 - ?Unknown Dominant? X Homozygous Recessive ROUND wrinkle ? RR -or- Rr ? We know is [[ rr ]] F1 - If offspring are ALL round, then unknown parent was ______________ If some offspring phenotype shows wrinkles, then the unknown parent was ___________

  39. Smiley : Genotype vs. Phenotype • Finished product - Word doc • DUE: Print/Color by Hand = HALL • POST TO WIKI - Go to YOUR HOUR’s PAGE, Upload Tool • Title at top : Genotype vs. Phenotype Smiley • Draw Smiley by “INSERT” > Pictures > AutoShapes • At Bottom: Name your Smiley • Give names: yours & partners • List Hour #

  40. Beyond Mendel More Complex Inheritance & Sex-Linked Traits

  41. Incomplete Dominance • An inheritance relationship in which a “mix” or blend of the two alleles is produced

  42. Incomplete Dominance • A cross between round radishes and long radishes produces oval radishes. (incomplete dominance). • A cross between round radishes and long radishes produces oval radishes. (incomplete dominance). If oval radishes were selling for the most money, what would you cross for highest profit? • round x round b. round x long • c. oval x oval d. long x oval

  43. Co-Dominance • Both alleles are visible in the phenotype • -examples- Lubber grasshopper or a roan horse--- or my sable corgi ! The lubber grasshopper is a very large grasshopper, and is black with red and yellow stripes.

  44. 1 RW: 0 • What is the expected genotypic ratio of the F1 generation? • What is the expected phenotypic ratio of the F1 generation? • What percent is expected to be white? • How do incomplete dominance and co-dominance differ? • Using your text, explain how blood typing illustrates both complete dominance and co-dominance? 1 roan: 0 0%

  45. Example 1: Homozygous x Homozygous Round (RR) Yellow (YY) seeds crossed with Wrinkled (rr) green (yy) seeds Genotypic Ratio: Phenotypic Ratio:

  46. Dihybrid Cross • Mono = One… so Monohybrid cross we were only focusing on ONE trait. • Di = Bi = Two So DiHybrid cross considers two traits at the same time.

  47. Dihybrid Cross pg. 171Round= R wrinkle= r // Yellow = Y green=y

  48. Example 2: Heterozygous x Heterozygous Round (Rr) Yellow (Yy) seeds crossed with Round (Rr) Yellow (Yy) seeds Genotypic Ratio: Phenotypic Ratio:

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