1. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition Solomon Berg Martin Chapter 10 The Basic Principles of Heredity

2. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity Terminology Phenotype Genotype Locus Allele Dominant allele Recessive allele Homozygous Heterozygous

3. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity Mendel’s principles of inheritance Segregation –During meiosis, alleles for each locus segregate Independent assortment –Alleles of different loci distributed randomly into the gamete –Results in recombination –Production of new gene combinations not found in parent

4. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity Seven characters in Mendel’s study of pea plants

5. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity One of Mendel’s pea crosses

6. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity Gene loci and their alleles

7. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity Monohybrid cross Cross between homozygous parents Differ at one locus Dihybrid cross Differ at two loci Test cross Between individual of unknown genotype and homozygous recessive individual

8. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity Monohybrid cross in guinea pigs

9. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity Dihybrid cross in guinea pigs

10. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity Test cross in guinea pigs

11. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity Genetic ratios can be expressed as probabilities Product rule predicts combined probability of independent events Sum rule predicts combined probability of mutually exclusive events

12. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity Rules of probability

13. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity Segregation Results from homologous chromosomes separating during meiosis Independent assortment Orientation of homologous chromosomes on the metaphase plate determines how chromosomes are distributed

14. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity Chromosomal basis for segregation

15. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity Linkage Tendency for a group of genes on same chromosome to be inherited together Recombination of linked genes Results from crossing-over in meiotic prophase I By measuring frequency of recombination, can construct linkage map of chromosome

16. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity Two-point test cross to detect linkage in fruit flies

17. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity Crossing-over

18. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity Sex chromosomes Cells of females of many species contain two X chromosomes Males have single X chromosome and single, smaller Y chromosome Y chromosome determines male sex in most species of mammals

19. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity Sex determination in mammals

20. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity X-linked red-green colorblindness

21. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity Dosage compensation in female mammals

22. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity Incomplete dominance Heterozygote is intermediate in phenotype Codominance Heterozygote simultaneously expresses the phenotypes of both homozygotes

23. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity Incomplete dominance in four o’clocks

24. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity

25. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity Multiple alleles in rabbits

26. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity Gene interaction in chickens

27. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity Epistasis in Labrador retrievers

28. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity Norm of reaction Range of phenotypic possibilities from a single genotype under different environmental conditions Example is height in human –Can be modified by factors such as diet –Genes that affect height set norm of reaction –Environment molds phenotype within norm of reaction

29. Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 10 The Basic Principles of Heredity Polygenic inheritance in human skin pigmentation