1. Principles of Heredity

2. Genetics – study of heredity => transmission of traits (genes) from one generation to another parent => offspring

3. Principles of Genetics Each individual trait (or gene) has a particular location on a chromosome (46 chromosomes hold 1000s of genes)

4. PHENOTYPE External traits you see External traits you see EX: hair color, eye color, height EX: hair color, eye color, height

5. GENOTYPE Internal genes that give a phenotype Internal genes that give a phenotype Use letters to represent Use letters to represent =ALLELE =ALLELE

6. GENOTYPE Use 2 alleles (letters) to represent a trait Use 2 alleles (letters) to represent a trait Why? Why? 2 parents 2 parents

7. 2 type of alleles DOMINANT (capital) DOMINANT (capital) RECESSIVE (small) RECESSIVE (small) F = freckles F = freckles f = no freckles f = no freckles

8. 2 type of alleles Only need 1 dominant gene to show that trait Only need 1 dominant gene to show that trait --> FF or Ff genotype “freckles” --> FF or Ff genotype “freckles”

9. LAW OF DOMINANCE - DOMINANT TRAIT (R) ALWAYS “MASKS” (COVERS UP) THE EXPRESSION OF THE RECESSIVE TRAIT (r).

10. 2 type of alleles Need 2 recessive genes to show that trait Need 2 recessive genes to show that trait --> ff = only genotype for “no freckles” --> ff = only genotype for “no freckles”

11. HOMOZYGOUS Both alleles are the same (“homo”) Both alleles are the same (“homo”) EX: FF or ff EX: FF or ff also called Purebred also called Purebred

12. HETEROZYGOUS Alleles are different (“hetero”) Alleles are different (“hetero”) EX: Ff EX: Ff also called Hybrid also called Hybrid

13. Identity the Genotype

14. GENETIC TERMINOLOGY CHECKPOINT 1. ALLELE – DOM. OR RECESSIVE FORM OF A GENE FOR A TRAIT. 1. ALLELE – DOM. OR RECESSIVE FORM OF A GENE FOR A TRAIT. (eg. SEED SHAPE: “R” AND “r”) (eg. SEED SHAPE: “R” AND “r”) 2. GENOTYPE - GENETIC MAKEUP OF ORGANISM. 2. GENOTYPE - GENETIC MAKEUP OF ORGANISM. (LETTER) COMBINATION OF ALLELES (eg. RR, Rr, rr). (eg. RR, Rr, rr). 3. PHENOTYPE - EXTERNAL FEATURE(S) 3. PHENOTYPE - EXTERNAL FEATURE(S) (eg. RED, SHORT, CURLY). 4. HOMOZYGOUS (PURE) – ALLELES ARE IDENTICAL 4. HOMOZYGOUS (PURE) – ALLELES ARE IDENTICAL (ex. BB, bb) 5. HETEROZYGOUS - (HYBRID) - ALLELE PAIRS DIFFERENT (ex. Bb) 5. HETEROZYGOUS - (HYBRID) - ALLELE PAIRS DIFFERENT (ex. Bb)

15. How was genetics discovered? Gregor Mendel = father of genetics Gregor Mendel = father of genetics Austrian Monk who work with large populations for pea plants Austrian Monk who work with large populations for pea plants

17. Mendel’s Pea Experiments Mendel’s Pea Experiments

19. SPERM + EGG = PEA PLANT SPERM + EGG = PEA PLANT * EACH GAMATE CONTRIBUTES A GENE TO DETERMINE TRAIT OF OFFSPRING!

20. PUNNETT SQUARE * CHART USED TO DETERMINE POSSIBLE COMBINATIONS OF GENES AMONG OFFSPRING IN A GIVEN GENETIC CROSS.