1. Genetics Chapter 7 Mr. Femia Biology Mr. Femia Biology

2. Heredity Heredity – characteristics inherited from parents to offspring through genes

3. Genetics The study of genes and heredity

4. Traits Characteristics that are inherited through genes

5. Gregor Mendel A monk in the 1800s First to identify heredity

6. Garden Peas Studied the traits in garden peas –Tall/short –Round/wrinkled –Green/yellow pods –Purple/white flowers

7. Background information Each trait or characteristic has 2 copies of DNA that code for that trait Each copy of the trait is called an allele Each organism has two copies of each allele

8. Conclusions Mendel had certain rules for heredity –Characteristic, unit factor/gene/height –Two contrasting traits/alleles/tall or short Another example pod color – green/yellow

10. The Rule of Dominance Alleles can be either dominant or recessive (strong or weak) –Dominant alleles are observable –Recessive alleles are not usually observable, when the dominant allele is present

11. The Law of Segregation Alleles for a gene separate when forming a sperm and egg

12. Law of Independent assortment Alleles for different genes are distributed to sperm and egg independently Could be –tall and fat –Short and thin –Tall and thin –Short and fat Why all siblings do not look exactly alike

13. Dominant The allele that is expressed – you can see it Use the first letter of the word and capitalize it C curly hair B brown hair

14. **Recessive** The allele that is not expressed It is covered up by the dominant allele It is there you just cannot see it Use the lower case for of the dominant allele c for straight hair b blonde hair

15. Phenotype The way an organism physically looks –Brown hair, tall

16. Genotype The copies of alleles or genes that an organism has BB, Bb, bb/ TT, Tt, tt

17. Homozygous – (homo same) Pure When an organism has 2 copies of the same allele BB – homozygous dominant bb – homozygous recessive

18. Heterozygous (hetero means different) Hybrid When an organism has 2 different alleles for a gene Bb, Gg etc.

19. Parent Generation P1 The 2 organisms that are used to reproduce

20. F1 generation The offspring - babies

21. F2 generation The babies of the F1 or the grandchildren of the P1

22. Incomplete dominance There is no dominant allele or recessive allele The 2 alleles are blended and make up a new physical appearance Ex. A red allele and a white allele can make a pink flower

23. Co dominance There is no dominant or recessive allele but both are expressed Ex: a chicken with white feathers mates with a chicken with black feathers and they have offspring with black and white feathers

25. **Punnett Square** A way of organizing genetics so that scientist can determine the genotype of the offspring of 2 individuals If 2 plants have a baby – predict what it would look like!

26. Monohybrid One cross because you are looking at only one trait

27. Dihybrid Two crosses - you are looking at 2 traits

29. Pedigree A diagram representing a family tree The alleles that each person in the family has

30. Monohybrid Punnett Square Problems Height – tall is dominant to short Symbol for tall _______ Symbol for short _____ Phenotype – –Homozygous tall male X short female Genotype –Male _____ X Female ______

31. P1 Punnett Square –F1 genotype ratio –F1 phenotype ratio

32. Monohybrid Punnett Square Problems Height – tall is dominant to short Symbol for tall _______ Symbol for short _____ Phenotype – _______ male X _______ female Genotype –Male _____ X Female ______

33. F1 Punnett Square –F2 genotype ratio –F2 phenotype ratio