The document discusses genetics concepts including: 1) Monohybrid crosses which result in a 3:1 phenotypic ratio between heterozygous and homozygous recessive offspring. 2) Dihybrid crosses which can produce multiple phenotypic ratios depending on if the genes are on the same or different chromosomes. 3) Incomplete dominance where heterozygotes display an intermediate phenotype between the homozygotes. 4) Test crosses which can be used to determine if genes are located on the same or different chromosomes based on observed offspring ratios.

1. Genetics

8. Fig. 14-5-3 P Generation Appearance: Genetic makeup: Gametes: Purple flowers White flowers PP P pp p F 1 Generation Gametes: Genetic makeup: Appearance: Purple flowers Pp P p 1 / 2 1 / 2 F 2 Generation Sperm Eggs P P PP Pp p p Pp pp 3 1

9. Fig. 14-6 Phenotype Purple Purple 3 Purple Genotype 1 White Ratio 3:1 (homozygous) (homozygous) (heterozygous) (heterozygous) PP Pp Pp pp Ratio 1:2:1 1 1 2

11. Purple Eyes

12. F 2 Offspring P F 1 F 2

13. Lobe Eyes

14. PTC

17. Black Body & Sepia Eyes

19. LE 9-18-3 F 1 generation All round yellow seeds ( RrYy ) Metaphase  of meiosis (alternative arrangements) Anaphase  of meiosis R r Y y R r R r y Y r R Y y R Y y y Metaphase  of meiosis Y R Y r R Y y r Y r y y y Y R R r r r y r y Y R R Y Gametes RY 1 4 1 4 ry 1 4 rY 1 4 Ry Fertilization among the F 1 plants F 2 generation 9 :3 :3 :1 (See Figure 9.5A)

20. Fig. 14-15 Key Male Female Affected male Affected female Mating Offspring, in birth order (first-born on left) 1st generation (grandparents) 2nd generation (parents, aunts, and uncles) 3rd generation (two sisters) Ww ww ww Ww Ww ww ww Ww Ww ww ww Ww WW or Widow’s peak No widow’s peak (a) Is a widow’s peak a dominant or recessive trait? 1st generation (grandparents) 2nd generation (parents, aunts, and uncles) 3rd generation (two sisters) Ff Ff Ff Ff Ff Ff FF or ff ff ff ff ff FF or Ff Attached earlobe Free earlobe (b) Is an attached earlobe a dominant or recessive trait?

21. Incomplete Dominance

23. Multiple Alleles & Codominance

26. Polygenic Inheritance

27. Fig. 14-13 Eggs Sperm Phenotypes: Number of dark-skin alleles: 0 1 2 3 4 5 6 1 / 64 6 / 64 15 / 64 20 / 64 15 / 64 6 / 64 1 / 64 1 / 8 1 / 8 1 / 8 1 / 8 1 / 8 1 / 8 1 / 8 1 / 8 1 / 8 1 / 8 1 / 8 1 / 8 1 / 8 1 / 8 1 / 8 1 / 8 AaBbCc AaBbCc 

30. Pleitropy

33. Nature versus Nurture

34. LE 9-UN178-3 Red RR  White rr Incomplete dominance Pleiotropy Polygenic inheritance Single gene Multiple genes Multiple traits Pink Rr Single trait (such as skin color)

37. X

39. Vestigle Wings & Black Body

41. Fig. 15-9-4 EXPERIMENT P Generation (homozygous) RESULTS Wild type (gray body, normal wings ) Double mutant (black body, vestigial wings)  b b vg vg b b vg vg Double mutant TESTCROSS  b + b + vg + vg + F 1 dihybrid (wild type) b + b vg + vg Testcross offspring Eggs b + vg + b vg b + vg b vg + Black- normal Gray- vestigial Black- vestigial Wild type (gray-normal) b vg Sperm b + b vg + vg b b vg vg b + b vg vg b b vg + vg PREDICTED RATIOS If genes are located on different chromosomes: If genes are located on the same chromosome and parental alleles are always inherited together: 1 1 1 1 1 1 0 0 965 944 206 185 : : : : : : : : :

42. Fig. 15-10b Testcross offspring 965 Wild type (gray-normal) 944 Black- vestigial 206 Gray- vestigial 185 Black- normal b + vg + b vg b vg b vg b + vg b vg b vg b + vg + Sperm b vg Parental-type offspring Recombinant offspring Recombination frequency = 391 recombinants 2,300 total offspring  100 = 17% b vg b + vg b vg + b vg + Eggs Recombinant chromosomes

43. LE 9-20a Tetrad Crossing over A B a b A B A b Gametes a b a B

44. LE 9-20c-b Explanation GgLl (female) ggll (male) g l g l g l g L G l g l G L G L g l Eggs Sperm Offspring G L g l G l g L g l g l g l g l

45. Fig. 15-11 RESULTS Recombination frequencies Chromosome 9% 9.5% 17% b cn vg

46. LE 9-21c Short aristae Black body ( g ) Cinnabar eyes ( c ) Vestigial wings ( l ) Brown eyes Red eyes Normal wings ( L ) Red eyes ( C ) Gray body ( G ) Long aristae (appendages on head) Mutant phenotypes Wild-type phenotypes