2. Gregor Mendel  In 1865, Gregor Mendel published studies of inheritance in pea plants.  During sexual reproduction, male and female gametes (reproductive cells; n) join to form a zygote (2n) in the process known as fertilization.

3. Heredity is… 1.Controlled by “factors.” (known as genes on chromosomes) 2.Passed from generation to generation. 3.Predicted Outcomes through Probability using Punnett Squares.

4. 1902 – Chromosome Theory of Heredity  Genes (Mendels “factors”) are located on chromosomes.  The different forms (variations) of a gene are called Alleles.  This is the basis for the modern science of Genetics.

5. Genetic Principles  Dominant and Recessive  Dominant = seen when present on the chromosome  Recessive = only seen when dominant allele is not present on the chromosome  Law of Segregation and Independent Assortment  Randomness  Placement of chromosomes within the process of meiosis  Genotype and Phenotype  Genotype – using letters to represent the trait’s alleles  Ex: Flower Color - FF, Ff, ff  Phenotype – using descriptive words (adjectives) to describe the trait’s alleles.  Ex: Flower Color – Purple or white  Homozygous and Heterozygous  Homozygous = same allele variations (TT, tt)  Heterozygous = difference allele variations (Tt)

6. Genes VS Alleles Gene Allele

7. Genes VS Alleles GenePlant HeightFlower Color Allele Tall PlantPurple Flowers Short PlantWhite Flowers

8. R.C. Punnett  In 1905, R.C. Punnett introduced the Punnett square.  Punnett squares can be used to predict and compare the genetic variations that will result from a cross (pg. 268).

9. Using Punnett Squares Yellow pea seed (Y) is DOMINANT to green (y). Genotype:YY x yy Phenotype: Yellowx green Parents (P)YY y y

10. Using Punnett Squares Yellow pea seed (Y) is DOMINANT to green (y). Genotype:YY x yy Phenotype: Yellowx green Parents (P)YY y y

11. Using Punnett Squares Yellow pea seed (Y) is DOMINANT to green (y). Genotype:YY x yy Phenotype: Yellowx green Parents (P)YY yYy y

12. Using Punnett Squares Yellow pea seed (Y) is DOMINANT to green (y). Genotype:YY x yy Phenotype: Yellowx green Parents (P)YY yYy y

13. Using Punnett Squares Yellow pea seed (Y) is DOMINANT to green (y). Genotype:YY x yy Phenotype: Yellowx green Parents (P)YY yYy y

14. Using Punnett Squares Yellow pea seed (Y) is DOMINANT to green (y). Genotype:YY x yy Phenotype: Yellowx green Parents (P)YY yYy y

15. Using Punnett Squares Yellow pea seed (Y) is DOMINANT to green (y). Genotype:YY x yy Phenotype: Yellowx green Parents (P)YY yYy y

16. Using Punnett Squares Yellow pea seed (Y) is DOMINANT to green (y). Genotype:YY x yy Phenotype: Yellowx green Parents (P)YY yYy y

17. Using Punnett Squares Yellow pea seed (Y) is DOMINANT to green (y). Genotype:YY x yy Phenotype: Yellowx green Parents (P)YY yYy y

18. Using Punnett Squares Yellow pea seed (Y) is DOMINANT to green (y). Genotype:YY x yy Phenotype: Yellowx green All (100%) offspring in F 1 Generation are Yellow hybrids. Parents (P)YY yYy y

19. Monohybrid Cross Yyx Yy Yellow xYellow F 1 GenerationYy

20. Monohybrid Cross Genotype: Yyx Yy Phenotype: Yellow x Yellow F 1 GenerationYy Y y

21. Monohybrid Cross Genotype: Yyx Yy Phenotype: Yellow x Yellow F 1 GenerationYy Y y

22. Monohybrid Cross Genotype: Yyx Yy Phenotype: Yellow x Yellow F 1 GenerationYy YYY y

23. Monohybrid Cross Genotype: Yyx Yy Phenotype: Yellow x Yellow F 1 GenerationYy YYY y

24. Monohybrid Cross Genotype: Yyx Yy Phenotype: Yellow x Yellow F 1 GenerationYy YYY yYy

25. Monohybrid Cross Genotype: Yyx Yy Phenotype: Yellow x Yellow F 1 GenerationYy YYY yYy

26. Monohybrid Cross Genotype: Yyx Yy Phenotype: Yellow x Yellow F 1 GenerationYy YYYYy y

27. Monohybrid Cross Genotype: Yyx Yy Phenotype: Yellow x Yellow F 1 GenerationYy YYYYy y

28. Monohybrid Cross Genotype: Yyx Yy Phenotype: Yellow x Yellow F 1 GenerationYy YYYYy y yy

29. Monohybrid Cross Genotype: Yyx Yy Phenotype: Yellow x Yellow Phenotypic Ratio: 75% (3/4) offspring are Yellow; Ratio is 3:4 (Yellow : total) 25% (1/4) offspring are green; Ratio is 1:4 (green : total) F 1 GenerationYy YYYYy y yy Genotype Ratio: 25% (1/4) offspring are YY, Ratio is 1:4 (homozygous dominant : total) 50% (2/4) offspring are Yy, Ratio is 1:2 (heterozygous : total) 25% (1/4) offspring are yy, Ratio is 1:4 (homozygous recessive : total)

30. Dihybrid Cross  Round pea seed (R) is dominant to wrinkled pea seed (r).  FOIL: YyRr  YR, Yr, yR, yr  (These are the possible genotypic combinations)

31. Dihybrid Cross Round pea seed (R) is dominant to wrinkled pea seed (r). Possible Combinations YRYryRyr YR Yr yR yr

32. Dihybrid Cross Round pea seed (R) is dominant to wrinkled pea seed (r). Possible Combinations YRYryRyr YRYYRRYYRrYyRRYyRr YrYYRrYYrrYyRrYyrr yRYyRRYyRryyRRyyRr yrYyRrYyrryyRryyrr

33. What is the probability that the plant will produce: Yellow, Round Peas: Yellow, Wrinkled Peas: Green, Round Peas: Green, Wrinkled Peas: Possible Combos YRYryRyr YR YYRR Yellow, Round YYRr Yellow, Round YyRR Yellow, Round YyRr Yellow, Round Yr YYRr Yellow, Round Yyrr Yellow, wrinkled YyRr Yellow, Round Yyrr Yellow, wrinkled yR YyRR Yellow, Round YyRr Yellow, Round yyRR green, Round yyRr green, Round yr YyRr Yellow, Round Yyrr Yellow, wrinkled yyRr green, Round Yyrr green, wrinkled

34. What is the probability that the plant will produce: Yellow, Round Peas: 9/16 Yellow, Wrinkled Peas:3/16 Green, Round Peas:3/16 Green, Wrinkled Peas:1/16 Possible Combos YRYryRyr YR YYRR Yellow, Round YYRr Yellow, Round YyRR Yellow, Round YyRr Yellow, Round Yr YYRr Yellow, Round Yyrr Yellow, wrinkled YyRr Yellow, Round Yyrr Yellow, wrinkled yR YyRR Yellow, Round YyRr Yellow, Round yyRR green, Round yyRr green, Round yr YyRr Yellow, Round Yyrr Yellow, wrinkled yyRr green, Round Yyrr green, wrinkled

35. To find the probability that two different events will happen at the same time, multiply the probabilities of each event happening separately.

36. Probability of offspring having YELLOW pea seeds: ¾ Probability of offspring having ROUND pea seeds: ¾ Probability of offspring having BOTH YELLOW AND ROUND PEAS: ¾ X ¾ = 9/16

37. Trihybrid Cross  Tall Stem (T) is dominant to short stem (t).  The probability of producing tall stems in a monohybrid cross is:  What is the probability that the offspring in a trihybrid cross will be Yellow, Round, and Tall?

38. Trihybrid Cross  Tall Stem (T) is dominant to short stem (t).  The probability of producing tall stems in a monohybrid cross is: ¾  What is the probability that the offspring in a trihybrid cross will be Yellow, Round, and Tall? ¾ X ¾ X ¾ = 27/64