Goal 3.03 Interpret and predict patterns of inheritance.

1. Goal 3.03 Interpret and predict patterns of inheritance. Let there be PEAS ON EARTH! And let it begin with me! math.uit.no

2. Gregor Mendel • 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

3. Mendel’s work Pollen transferred from white flower to stigma of purple flower When bred to themselves will always produce organisms with same phenotype. EX. White bred to white always produces white; purple bred to purple always produces purple. • Bred pea plants • cross-pollinate true breeding parents • raised seed & then observed traits • allowed offspring to self-pollinate& observed next generation anthers removed all purple flowers result When a flower pollinates itself. No new genes are introduced. self-pollinate ?

4. Mendel collected data for 7 pea traits Each of these traits is represented by a specific allele on a specific chromosome. Allele = genes that determine a specific trait. Flower color Seed color Seed shape Pod color Pod shape Flower location Plant size

5. true-breeding white-flower peas true-breeding purple-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

6. 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 mutant allele malfunctioningprotein allele producingfunctional protein homologouschromosomes

7. X P purple white F1 all purple Genotype vs. phenotype • Difference between how an organism “looks” & its genetics • phenotype • Form of the trait that gets expressed“what you see” • genotype • An organism’s actual alleles Explain Mendel’s results using …dominant&recessive …phenotype&genotype

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

9. Phenotype is a result of both genetics and environment. Cold Environment Siamese cats that grow up in a cold environment are darker… www.safeandsoundlostandfound.org …than those that grow up in a warmer environment. Warm Environment www.cats-central.com

10. 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?)

11. Remember how Meiosis separates the alleles into sex cells? This separation is called the Law of Segregation.

12. Effect of genes • Genes come in different versions - alleles • brown vs. blue eyes • brown vs. blonde hair • Alleles = different forms of a gene

13. Homozygous dominant = AA Homozygous recessive = aa Heterozygous = Aa Homozygous = same Heterozygous = different aa rr XY Ss Ww Tt Aa Yy BB RR Ee bb AB Bb

14. Genes affect how you look… X bb BB Bb Bb Bb Bb Where did the blue eyes go??

15. X bb Bb Bb Bb bb bb Why did the blue eyes stay??

16. X Bb Bb bb BB or Bb BB or Bb BB or Bb Where did the blue eyes come from??

17. Genes come in “versions” • brown vs. blue eye color • Alleles (different forms of a gene) • 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

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

19. 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 (copies) of chromosomes 1 from Mom homologous chromosomes 1 from Dad

20. B B B b b b BB Bb bb Making gametes BB = brown eyes bb= blues eyes Bb= brown eyes Dominant = can mask others  brown is dominant over blue  blue is recessive to brown Recessive = can be hidden by others Remember meiosis!

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

22. Punnett squares B b B b Bb x Bb male / sperm X BB Bb female / eggs Bb bb Punnett square practice.

23. 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

24. 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.

25. PP pp x X P purple white F1 all purple 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

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

27. Any Questions?? Assignment: Punnett Square Practice Worksheet www.publispain.com

28. Beyond Mendel’s Lawsof Inheritance

29. Extending Mendelian genetics • Mendel worked with a simple system • peas are genetically simple • most traits are controlled by single gene • each gene has only 2 version • 1 completely dominant (A) • 1 recessive (a) • But its usually not that simple!

30. Incomplete dominance • Hybrids have “in-between” appearance • RR = red flowers • rr = white flowers • Rr = pink flowers • make 50% less color RR WW or R’R’ RW or RR’ RR Rr rr

31. 100% pink flowers 1st generation (hybrids) 100% 25% red 50% pink 25% white 1:2:1 2nd generation Incomplete dominance X true-breeding red flowers true-breeding white flowers P self-pollinate

32. RR 25% 25% male / sperm R W RW 50% 50% R RW female / eggs WW W 25% 25% Incomplete dominance RW x RW % genotype % phenotype 1:2:1 1:2:1

33. Codominance • Equal dominance • Chickens • A black-feathered chicken is crossed with a white-feathered chicken. • All of the babies are white with black speckling. • Both white and black show up equally. = x

34. More Codominance… x

35. Multiple Alleles • More than one allele to select from. • Blood “types” can be A, B, AB, or O. • The alleles to make these types include A, B and i. • “i” is the recessive allele and A and B are both dominant. • So to get… • Type A you must have AA or Ai • Type B you must have BB or Bi • Type AB you must have AB • Type O you must have ii

36. BLOOD Antigens are tiny receptors on the outside of the blood cell that matches the “type.” Multiple Alleles Blood cells have antigens and antibodies. Antibodies are what the cell doesn’t like (which is anything different from the “type.”)

37. Blood Types Multiple Alleles A B Anti-A Anti-B Type A Type B A B A B Antigens (none) A B Type O Type AB B Anti-A and B none A

38. Genetics of Blood type Multiple Alleles

39. One gene : Many effects? • The genes that we have covered so far affect only one trait • But most genes are affect many traits • 1 gene affects more than 1 trait • dwarfism (achondroplasia) • gigantism (acromegaly)

40. Acromegaly: André the Giant

41. Inheritance pattern of Achondroplasia Aa x aa Aa x Aa A a A a a Aa aa A AA Aa a Aa a aa Aa aa 50% dwarf:50% normal or1:1 67% dwarf:33%normalor2:1

42. Many genes : One trait Polygenic =“many genes” • Polygenic inheritance • additive effects of many genes • humans • skin color • height • weight • eye color • intelligence • behaviors

43. Human skin color Polygenic =“many genes” • AaBbCc x AaBbCc • range of shades • most children = intermediate skin color • some can be very light & very dark

44. Albinism Johnny & Edgar Winter melanin = universal brown color albinoAfricans

45. OCA1 albino Bianca Knowlton

46. Coat color in other animals • 2 genes: E,eandB,b • color (E) or no color (e) • how dark color will be: black (B) or brown(b) E–bb eebb eeB– E–B–

47. SEX and GENES • Women & men are very different, but just a few genes create that difference • In mammals = 2 sex chromosomes • X & Y • 2 X chromosomes = female: XX • X & Y chromosome = male: XY • X only = XO (Turner’s Syndrome) X X X Y

48. Who you are… Autosomes SexChromosomes

49. Sex-linked traits • Sex chromosomes have other genes on them, too • especially the X chromosome • hemophilia in humans • blood doesn’t clot • Duchenne muscular dystrophy in humans • loss of muscle control • red-green color blindness • see green & red as shades of gray X X X Y

50. HH XHXH XHXh XHXh XHXh Hh XH XHY XHY XhY Xh male / sperm XH Y XHXH XHY XH XHY XH female / eggs Y Xh XhY XHXh sex-linked recessive x 2 normal parents, but mother is carrier