1. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-1 Human Genetics Concepts and Applications Seventh Edition Powerpoint Lecture Outline Ricki Lewis Prepared by Mary King Kananen Penn State Altoona

2. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-2 Chapter 14 When Allele Frequencies Stay Constant

3. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-3 Population Is an interbreeding group of the same species within a given geographical area Gene pool - the collection of all alleles in the members of the population Population genetics - the study of the genetics of a population and how the alleles vary with time Gene Flow - alleles can move between populations when individuals migrate and mate

4. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-4 Allele Frequencies Allelic # of particular allele Frequency total # of alleles in the population Count both chromosomes of each individual Allele frequencies affect the genotype frequencies –The frequency of each type of homozygote and heterozygote in the population

5. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-5 Phenotype Frequencies Frequency of a trait varies in different populations Table 14.1

6. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-6 Microevolution Genetic change due to changing allelic frequencies in populations Allelic frequencies can change when: –Nonrandom mating –Gene flow –Genetic drift –Natural selection (unequal reproductive success) Macroevolution –The formation of new species

7. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-7 Hardy-Weinberg Equilibrium Developed by mathematicians A condition in which allele frequencies remain constant Used in algebra to explain how allele frequencies predicts genotype and phenotype frequencies in equilibrium

8. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-8 Hardy-Weinberg Equilibrium p + q = 1 p = allele frequency of one allele q = allele frequency of a second allele p 2 + 2pq + q 2 = 1 p 2 and q 2 genotype frequencies for each homozygote 2pq genotype frequency for heterozygotes All of the allele frequencies together equals 1 or the whole collection of alleles All of the genotype frequencies together equals 1

9. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-9 Figure 14.1

10. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-10 Hardy-Weinberg Equilibrium Generation 1 p allele frequency of D normal finger length =.7 q allele frequency of d short middle finger =.3 DD p 2 = (.7) 2 =.49 Genotype frequencies Dd 2pq = 2 (.7)(.3) =.42 dd q 2 = (.3) 2 =.09 Gamete frequencies.49.21.21.09 Frequency D gamete =.7 frequency d gamete =.3

11. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-11 Hardy-Weinberg Equilibrium Figure 14.2

12. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-12 Hardy-Weinberg Equilibrium Figure 14.2

13. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-13 Figure 14.3

14. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-14 Populations Vary Frequency of an allele may vary between populations An illness may be common in one group but rare elsewhere 60 known cases of Crigler- Najjar syndrome, many are found in Mennonite and Amish communities in Lancaster, Pa Figure 14.3

15. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-15 Calculating the Carrier Frequency of an Autosomal Recessive Figure 14.4

16. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-16 Carrier Frequency for Cystic Fibrosis Table 14.4

17. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-17 Females: p 2 + 2pq + q 2 = 1 Males:p + q = 1 All of the women in the population All of the men in the population Calculating Risk with X-linked Traits Hemophilia is X-linked and occurs in 1 in 10,000 males p = 1/10,000 =.0001therefore q =.9999 Carrier females = 2pq = 2 (.0001) (.9999) =.0002 1 in 5000 are carriers Affected females = p 2 = (.0001) 2 =.00000001 1 /100 million women will have hemophilia

18. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-18 Calculating Carrier Frequency for X-linked Traits Figure 14.5

19. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-19 DNA Profiling Hardy-Weinberg equilibrium applies to portions of the genome that do not affect phenotype They are not subject to natural selection Short repeated segments that are not protein encoding Uses SNPs or Single nucleotide polymorphisms Single base differences between chromosomes Repeated sequences Variation in the number of repeats present

20. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-20 DNA Profiling Repeats are distributed all over the genome Detects differences in repeat copy number Calculates probability that certain combinations can occur in two sources of DNA Requires molecular techniques and population studies

21. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-21 Table 14.5

22. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-22 Comparing DNA Repeats Figure 14.6

23. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-23 DNA Profiling Developed in 1980s Identifies individuals Used in forensics, agriculture, paternity testing, and historical investigations DNA can be obtained from many sources

24. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-24 Figure 14.7

25. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-25 DNA Identification Figure 14.8

26. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-26 A Sneeze Identifies Art Thief Table 14.6

27. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-27 DNA Profiling Techniques (1) A blood sample is collected from suspect (2) White blood cells release DNA (3) Restriction enzymes cut DNA (4) Electrophoresis aligns fragments by size (5) Pattern of DNA fragments transferred to a nylon sheet

28. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-28 (6) Exposed to radioactive probes (7) Probes bind to DNA (8) Sheet placed against X ray film (9) Patten of bands constitutes DNA profile (10) Identify individuals DNA Profiling Techniques

29. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-29 Box Figure 14.1

30. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-30 Comparing DNA Sequences Figure 14.9

31. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-31 DNA Profiles Databases are essential for statistical analysis Nuclear and mitochondrial DNA can be used Very small amounts of DNA can be used Recent examples of large scale analysis –World Trade Center victims –2004 Asian tsunami disaster

32. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14-32 Genetic Privacy Concerns Health Insurance Portability and Accountability Act (HIPAA)