1. Genetics: The study of heredity

2. Heredity = the passing of traits from parents to offspring

3.  Trait = A feature or characteristic of a person  Physical appearance  Behavior tendencies  Predisposed to medical conditions  A person’s traits are influenced by:  their genetic inheritance  environmental factors What is a trait? What is a trait?

4. Trait = a feature or characteristic of a person  Physical appearance  Genetics:  Environment: eye color hair color smile shape hair texture face shape

5. Trait = a feature or characteristic of a person  Physical appearance  Genetics: genes determine natural hair color  Environment: eye color hair color smile shape hair texture face shape

6. Trait = a feature or characteristic of a person  Physical appearance  Genetics: genes determine natural hair color  Environment: sun or hair dyes change hair color eye color hair color smile shape hair texture face shape

7. Trait = a feature or characteristic of a person  Behavior tendencies  Genetics:  Environment:

8. Trait = a feature or characteristic of a person  Behavior tendencies  Genetics: genes determine the tendency to use a certain hand  Environment:

9. Trait = a feature or characteristic of a person  Behavior tendencies  Genetics: genes determine the tendency to use a certain hand  Environment: can learn to use the opposite hand

10. Trait = a feature or characteristic of a person  Predisposed to medical conditions  Genetics:  Environment:

11. Trait = a feature or characteristic of a person  Predisposed to medical conditions  Genetics: genes determine a risk of heart disease  Environment:

12. Trait = a feature or characteristic of a person  Predisposed to medical conditions  Genetics: genes determine a risk of heart disease  Environment: eating healthy foods and exercising can reduce risk

13. Trait = a feature or characteristic of a person  Phenotype = a person’s version of a trait  “physical appearance” eye color: blue hair color: black hair texture: straight

14. Practice  List 3 traits Dash has.  List Dash’s phenotype for each trait.

15. Trait = a feature or characteristic of a person  Gene = part of a person’s DNA that influences a trait Eye color gene Hair color gene Face shape gene

16. Gene = part of a person’s DNA that controls a trait  Alleles= different versions of a gene Eye color gene: brown allele Eye color gene: blue allele

17. Practice  List 3 possible alleles for the hair color gene. Hair color gene

18. Alleles = different versions of a gene  Dominant Allele  Represented by a capital letter  Example: B for brown eyes  Recessive allele  Represented by a lowercase letter  Example: b for blue eyes

19. Alleles = different versions of a gene  All people have 2 alleles for every gene (one from each parent) Allele of eye color gene from mom Allele of eye color gene from dad

20. Alleles = different versions of a gene  All people have 2 alleles for every gene (one from each parent)  Genotype = a person’s combination of alleles  “genetic makeup” Allele of eye color gene from mom Allele of eye color gene from dad

21. Genotype = a person’s combination of alleles  A person may inherit 2 of the same alleles = homozygous/purebred  2 dominant alleles = homozygous dominant  Example: B and B Genotype = Phenotype = EE MomDad Child

22. Genotype = a person’s combination of alleles  A person may inherit 2 of the same alleles = homozygous/purebred  2 dominant alleles = homozygous dominant  Example: B and B Genotype = BB Phenotype = EE MomDad Child

23. Genotype = a person’s combination of alleles  A person may inherit 2 of the same alleles = homozygous/purebred  2 dominant alleles = homozygous dominant  Example: B and B Genotype = BB Phenotype = brown eyes EE MomDad Child

24. Genotype = a person’s combination of alleles  A person may inherit 2 of the same alleles = homozygous/purebred  2 recessive alleles = ee MomDad Child

25. Genotype = a person’s combination of alleles  A person may inherit 2 of the same alleles = homozygous/purebred  2 recessive alleles = homozygous recessive  Example: b and b Genotype = Phenotype = ee MomDad Child

26. Genotype = a person’s combination of alleles  A person may inherit 2 of the same alleles = homozygous/purebred  2 recessive alleles = homozygous recessive  Example: b and b Genotype = bb Phenotype = ee MomDad Child

27. Genotype = a person’s combination of alleles  A person may inherit 2 of the same alleles = homozygous/purebred  2 recessive alleles = homozygous recessive  Example: b and b Genotype = bb Phenotype = blue eyes ee MomDad Child

28. Alleles = different versions of a gene  A person may inherit 2 different alleles = heterozygous/hybrid  Dominant allele masks recessive allele  Example: B and b Genotype = Phenotype = Ee MomDad Child eE MomDad Child -or-

29. Alleles = different versions of a gene  A person may inherit 2 different alleles = heterozygous/hybrid  Dominant allele masks recessive allele  Example: B and b Genotype = Bb Phenotype = Ee MomDad Child eE MomDad Child -or-

30. Alleles = different versions of a gene  A person may inherit 2 different alleles = heterozygous/hybrid  Dominant allele masks recessive allele  Example: B and b Genotype = Bb Phenotype = brown eyes Ee MomDad Child eE MomDad Child -or-

31. Practice  Brown hair (B) is dominant to blond hair (b). GenotypePhenotype homozygous dominant homozygous recessive heterozygous

32. Practice  Brown hair (B) is dominant to blond hair (b). GenotypePhenotype homozygous dominant BB Brown hair homozygous recessive heterozygous

33. Practice  Brown hair (B) is dominant to blond hair (b). GenotypePhenotype homozygous dominant BB Brown hair homozygous recessive bb Blond hair heterozygous

34. Practice  Brown hair (B) is dominant to blond hair (b). GenotypePhenotype homozygous dominant BB Brown hair homozygous recessive bb Blond hair heterozygousBb Brown hair Which genotypes are purebred? Which is hybrid?

35. Practice  Right-handedness (R) is dominant to left-handedness (r). What genotype(s) could a right-handed person have? What genotype(s) could a left-handed person have? RR or Rr rr

36. Practice  In pea plants, green peas (G) are dominant to yellow peas (g). What would be the genotype of a: -purebred green pea? -hybrid green pea? -yellow pea? GG Gg gg