This document provides an overview of human genetics concepts and applications. It discusses that genetics is the study of inherited traits and genes, which contain DNA instructions for protein production. The human genome was sequenced in 2000. Genetic testing can detect health-related variants and provide risk information. Counseling helps explain genetic testing results. Examples of tests include those for cystic fibrosis and certain cancers. DNA and RNA are described, as are genes, alleles, chromosomes, karyotypes, levels of biological organization, genotypes, phenotypes, pedigrees, populations, and evolution. Applications of genetics include forensics, health care, agriculture, and ecology.

1. Human Genetics Concepts and Applications Seventh Edition Powerpoint Lecture Outline Ricki Lewis Prepared by Mary King Kananen Penn State Altoona Edited RP Fall 2007

2. Overview of Genetics Chapter 1

3. Genetics Is a life science It is the study of inherited variation and traits Genes are the units of heredity Genes are composed of Deoxyribonucleic Acid ( DNA) Traits are produced by an interaction between the genes and the environment

4. Genes Contain the instructions within the cells for protein production Figure 1.1

5. The Genome Is the complete set of genetic information for an organism It includes: All of the genes present in an organism and Other DNA sequences that do not encode genes Human genome was sequenced in 2000

6. Genetic Testing Uses new technology Detects health-related genetic variants May be used To prevent, delay, control, or treat symptoms Gain information on risk of genetic diseases and for pre-pregnancy testing Personalize medical treatment

7. Steps in Genetic Testing Figure 1.2

8. Genetic Counseling Genetic counselor recommends tests and explains the findings from the laboratory testing Confidentiality is important Laws prevent employers and insurers from discriminating against anyone based on genetic information

9. Examples of Genetic Tests Cystic fibrosis Certain cancers Inherited forms of Alzheimer's Type 2 diabetes Others

10. Levels of Genetics Figure 1.3

11. Deoxyribonucleic Acid (DNA) A double stranded polymer consisting of a chain of nucleotides Deoxyribonucleotide components: Phosphate Sugar : Deoxyribose Base : Guanine G Adenine A Thymine T Cytosine C The sequence of the bases code for the amino acid sequence in a protein

12. Box Figure 1.1

13. Ribonucleic Acid (RNA) Single stranded polymer of ribonucleotides Ribonucleotides components: Phosphate Sugar : Ribose Base : Guanine G Adenine A Uracil U Cytosine C Several types Uses information on DNA to construct proteins

14. Box Figure 1.2

15. Genome Only 1.5% of the DNA in the human genome encodes protein Rest includes highly repeated sequences with unknown functions Includes about 24,000 protein encoding genes Cataloged in database Online Mendelian Inheritance in Man (OMIM)

16. Genes Alleles are variants of genes They form by mutation Mutations in sperm or egg cells are passed on to the next generation May be positive, negative, or neutral Examples

17. Variations Polymorphisms are variations in the DNA sequence that occur in at least 1% of the population Single nucleotide polymorphisms (SNPs) are single base sites that differ among individuals and are important as markers

18. Chromosomes Composed of DNA and protein Found in the nucleus of the cell Human cells have 46 chromosomes 22 pairs of autosomes The sex chromosomes X and Y Females have two X chromosomes Males have one X and a Y

19. A Karyotype is a chart of the chromosomes organized by the size of the chromosome pairs. Figure 1.3

20. Cells All cells with a nucleus in the body contain the same genetic information Differentiation causes cells to differ in appearance and function. This is controlled by variation in gene expression. Stem cells are less specialized

21. Levels of Organization Cells Tissues Organs Organ systems Organism

22. Individual The genotype of an individual is the alleles they carry The phenotype is the visible trait Dominant alleles are expressed if the individual carries one or two copies of the allele Recessive alleles are only expressed if the individual carries two copies of the allele

23. The Family Inheritance of traits can be observed in families. A pedigree indicates the structure of a family schematically. Figure 1.3

24. A Population Is a group of interbreeding individuals The gene pool is the alleles in a population Evolution is the changing allelic frequencies in populations over time. Figure 1.3

25. Evolution Comparison of DNA sequences indicates the amount of similarity between two species. 98% of human DNA sequences are shared with chimpanzees. Humans share genes with mice, fish, fruit flies, yeast, and bacteria . Figure 1.5

26. Two random people share approximately 99.9% of their genome Concept of “race” as defined by skin color is a social, not a biological, concept Studies indicates humans arose in Africa and migrated across the globe with relatively little change. Variation in the Human Population

27. Review of Genetic Terms Table 1.1

28. Most Genes Do Not Function Alone Mendelian traits are determined by a single gene Most traits are multifactorial and not controlled by a single gene. They are influenced by more than one gene and the environment Some illnesses may occur in different forms: Mendelian, multifactorial, and non-inherited

29. Genetic Risk Absolute risk the probability that an individual will develop a condition or trait Relative risk the likelihood that an individual from one group will develop a condition in comparison to another group (usually the general population) Empiric risk risk determined by observing incidence of a trait in the population Risk factor a situation that alters incidence of a disease (or trait)

30. Relative Risk Figure 1.7

31. DNA profiling compares DNA sequences to Establish relationships Forensics Biobanks Applications of Genetics Box Table 1.1

32. Applications of Genetics Historical Common origins Figure 1.9

33. Figure 1.10

34. Applications of Genetics Health care Prediction of disease Development of treatments Family planning

35. Applications of Genetics Agriculture Crop and animal breeding Genetically modified foods Pest management Figure 1.12

36. Applications of Genetics Ecology