1. 1 Mendelelian Genetics GPS: Using Mendel’s laws, explain the role of Meiosis in reproductive variability

2. Gregor Mendel (1822-1884)  Studied the inheritance of traits in pea plants  Developed the laws of genetics  aka “Father of Genetics”

3.  Mendel stated that physical traits are inherited as “particles”  Mendel did not know that the “particles” were actually GENES Particulate Inheritance

4. Genetic Terminology  Trait - any characteristic that can be passed from parent to offspring  Heredity - passing of traits from parent to offspring  Genetics - study of heredity

5. Types of Genetic Crosses  Punnett Square - cross involving a single trait e.g. flower color  AKA Monohybrid cross  Dihybrid cross - cross involving two traits e.g. flower color & plant height

6. Punnett Square A diagram used to show the probability of a trait being present in offspring.

7. “Genes”  Alleles - two forms of a gene (dominant & recessive)  Dominant - stronger of two genes. Expressed in a cross; represented by a capital letter (R)  Recessive - gene that shows up less often in a cross; is dominated or overpowered by the dominant gene; represented by a lowercase letter (r)

8. More Terminology  Genotype – genetic makeup or gene combination for a trait (e.g. RR, Rr, rr)  Phenotype - the physical feature resulting from a genotype (e.g. red, white)

9. Genotypes  Homozygous genotype - gene combination where both alleles are the same (e.g. RR or rr); also called pure bred  Homozygous genotype - gene combination where both alleles are the same (e.g. RR or rr); also called pure bred  Heterozygous genotype - gene combination where the alleles are different (e.g. Rr); also called hybrid

10. 10 Mendel’s Laws

11. Law of Dominance Some alleles are dominant and some are recessive.Some alleles are dominant and some are recessive. When combined in a hybrid, the dominant overpowers the recessive.Like  RrWhen combined in a hybrid, the dominant overpowers the recessive.Like  Rr The dominant form of the trait ALWAYS shows in the phenotype.The dominant form of the trait ALWAYS shows in the phenotype.

12. Law of Dominance T = tall (dominant) t = short (recessive) TT – tall Tt – tall tt - short R = round (dominant) r = wrinkled (recessive) RR – round Rr – round rr - wrinkled Y = yellow (dominant) y = green (recessive) YY – YY – Yy – Yy – yy - yy - P = purple (dominant) p = white (recessive) PP – PP – Pp – Pp – pp - pp -

13. Law of Segregation During meiosis, the two alleles responsible for a trait separate from each other. (when the homologous chromosomes separate) Alleles for a trait are "recombined" at fertilization Study diagram!!!

14. Law of Segregation

15. Let’s Practice Using SpongeBob!!! Assignments For Today!! Begin Spongebob Practice Sheet Watch Video to Better Understand How to use Punnett Squares. Practice Doing Punnett Squares – Spongebob Worksheet. Complete Lecture Quiz  Paper Pet Genetics  Power Notes

16. Male Gametes Male Parent MEIOSIsMEIOSIs Meiosis Female Parent Female Gametes

17. Law of Independent Assortment Alleles for different traits are distributed to the gametes independently of one another. This law can be illustrated using dihybrid crosses.

18. GENOTYPE vs. PHENOTYPE B – brown eyes (dominant) b – blue eyes (recessive) What are the possible genotypes for brown eyes? What are the possible genotypes for blue eyes? W – widow’s peak ( ? ) w – no widow’s peak ( ? ) Possible genotypes for having a widow’s peak: Possible genotypes for not having a widow’s peak:

19. HETEROZYGOUS vs. HOMOZYGOUS F – free earlobe (dominant) f – attached earlobe (recessive) FF – homozygous Ff – ff - H – hitchhiker’s thumb ( ? ) h – no hitchhiker’s thumb ( ? ) HH – hh – Hh -

20. PUNNETT SQUARES

21. Trait: Seed Shape Alleles: R – Round r – Wrinkled Cross: homozygous Round seeds x Wrinkled seeds x Genotype: Phenotype Genotypic Ratio: Genotype: Phenotype: Genotypic Ratio: Phenotypic Ratio:

22. Trait: Seed Shape Alleles: R – Roundr – Wrinkled Cross: Heterozygous Round seeds x Heterozygous Round seeds x Genotype: Phenotype Phenotype:G.Ratio:P.Ratio:

23. Trait: Seed Shape Alleles: R – Roundr – Wrinkled Cross: Homozygous Round seeds x Heterozygous Round seeds Genotype: Phenotype Genotypic Ratio: Phenotype: Genotypic Ratio: Phenotypic Ratio:

24. Male Gametes Male Parent MEIOSIsMEIOSIs Meiosis Female Parent Female Gametes

25. Male Gametes Male Parent MEIOSIsMEIOSIs Meiosis Female Parent Female Gametes

26. Dihybrid Cross ▪ Examines the cross of 2 different traits Y = Yellow (dominant) y = green (recessive) R = Round (dominant) r = wrinkled (recessive) Cross 2 heterozygous yellow, heterozygous round plants: what are the genotypes? Seed color Seed shape

27. Y = Yellow y = green R = Round r = wrinkled YyRr YyRr

32. Summary of Mendel’s laws LAW PARENT CROSS OFFSPRING DOMINANCE TT x tt tall x short Tt 100% tall SEGREGATION Tt x Tt tall x tall 75% tall 25% short INDEPENDENT ASSORTMENT RrGg x RrGg round & green x round & green 9/16 round seeds & green pods 3/16 round seeds & yellow pods 3/16 wrinkled seeds & green pods 1/16 wrinkled seeds & yellow pods

33. Non-Mendelian Inheritance

34. Incomplete Dominance One trait is not dominant over the other. The offspring’s trait is a mixture of the 2 parents. +

35. Codominance One trait is not dominant over the other. Both alleles are expressed in the offspring. + = WWBB WB

36. + = Homozygous Red Roan Homozygous White

37. Human Blood type

38. POLYGENETIC TRAIT ▪ Trait produced by 2 or more genes that interact ▪ Human skin color ▪ Human eye color Order of dominance: brown > green > blue.

39. SEX LINKED TRAITS ▪ Genes located on sex chromosomes are called sex-linked genes. ▪ Y chromosome genes in mammals are responsible for male characteristics. ▪ X chromosome genes in mammals affect many traits.

40. SEX LINKED TRAITS Most sex linked (X-linked) disorders are recessive and show up only in males. Females are carriers of sex linked disorders

41. PEDIGREES ▪ A pedigree is a chart for tracing genes in a family ▪ Trace phenotypes to infer the genotypes -Male carrier Autosomal genes: widow’s peak -Male without trait -Male with trait -Female without trait -Female with trait -Female carrier -Male carrier

42. Sex Linked genes: colorblindness M – normal color vision m - colorblind -Male without trait -Male with trait -Female without trait -Female with trait -Female carrier -Male carrier