1. Extending Mendelian Genetics
Chapter 7 page 186

2. A. Chromosomes and Phenotype
2 copies of each autosomal gene affect phenotype
Inherit 1 set of chromosomes from each parent
Homologous chromosomes could have same gene but different alleles
Gene expression often related to whether the gene is on an autosome or sex chromosome

3. d. Disorders caused by recessive alleles 1) Only homozygous recessive individuals express the disorder 2) Carrier – does not show symptoms but can pass on the disease 3) Parents are typically heterozygous for the trait 4) Ex – Cystic fibrosis

4. Punnett Square for Cystic Fibrosis

5. e. Disorders caused by dominant alleles 1) Less common than recessive disorders 2) At least one parent will have the disorder 3) Huntington’s disease

6. 2. Sex-linked traits a. Sex-linked genes 1) Genes located on the sex chromosomes 2) XX genotype = female and XY genotype = male 3) Females can only give an X, males can give an X or Y

7. 4) Genes on X and Y chromosomes are sex-linked 5) X chromosome carries nearly 1100 genes, but the Y chromosome has less than 250 6) More traits are controlled by the X chromosome

8. b. Expression of sex-linked genes 1) Sex linked traits are more common in males a) Males only have 1 X chromosome b) One recessive trait on an X chromosome gives an expressed trait 2) Females a) X chromosome inactivation – 1 X chromosome is randomly turned off

9. Female
b) Causes a “patch work” of different genes in cells c) Female calico and tortoiseshell cats
Male

10. B. Complex Patterns of Inheritance
Incomplete Dominance
Heterozygous phenotype is b/w the two homozygous phenotypes
Neither is completely dominant or recessive
Beta fish and snap-dragon

11. Incomplete dominance
Green (B1B1) Steel Blue (B2B2) Royal Blue (B1B2)

12. 2. Codominance a. Both traits are expressed equally b
2. Codominance a. Both traits are expressed equally b. Red flowers x white flowers = red and white patches c. Blood type 1) A and B alleles are codominant 2) O allele is recessive 3) A and B blood means you make proteins called antigens

13. Human Blood Types

14. 3. Polygenic Traits a. Traits produced by two or more genes b
3. Polygenic Traits a. Traits produced by two or more genes b. Skin, eye, and fur color c. Green dominant over blue yet recessive to brown

15. d. Epistatic gene 1) Interferes with all other gene expression 2) Can cause albinism

16. 4. Environmental influence a
4. Environmental influence a. Gender of turtles before hatching 1) Warm temperatures = females 2) Cooler temperatures = males b. Genotypes may express different phenotypes 1) Hair changes color in summer from the sun 2) Artic fox has white fur in winter and brown in summer c. Identical twins raised in different environments

17. 29˚ C = 84.2˚ F

18. Arctic Fox
Summer
Winter

19. C. Human Genetics and Pedigrees
Studying genetics of simple organisms helps us understand our genetics
Genetics are the same in all sexually reproducing organisms
Inheritance of many human traits is very complex

20. 4. Females can carry sex-linked disorders a
4. Females can carry sex-linked disorders a. Males only have 1 X chromosome 1) They express every X-linked trait (dominant or recessive) 2) Nothing to mask recessive traits 3) Males can’t be carriers of sex-linked traits only females b. Expression of disorder depends on: 1) Which parent carries the allele 2) Sex of the child

21. c. Ex: Hemophilia and color blindness

22. 5. Pedigrees a. Chart which traces geno/phenotypes in a family to determine if people are carriers b. Used by genetic counselors to determine probability of parents having children with genetic disorders c. Determining autosomal trait or sex-linked: 1) Sex-linked – appear more often with males 2) Autosomal – appear equally b/w both males and females

23. d. Key 1) Boxes – males 2) Circles – females 3) Shaded – person expresses trait 4) Half shaded – person is a carrier 5) Line through it – person has died 6) Connecting lines – shows mate or children

25. Colorblindness

26. Colorblindness Test

27. # #4

28. # #6

29. # #8

30. Fig. 4.4 pg 204

31. 6. Karyotypes a. Genome – all DNA in a cell b
6. Karyotypes a. Genome – all DNA in a cell b. Karyotype – picture of all chromosomes in a cell c. Used to detect large changes like #, size, or shape of chromosomes d. Human Genome Project 1) International effort 2) Tries to map, sequence, and ID all genes in human genome

32. Human Karyotype
Is this karyotype from a male or female?