1. Lecture Topic: “Genetic Control of Cellular Function/Gene Technology” l Explain the mechanisms whereby genetic information is passed from one generation to another. l Define gene mapping. l Identify goal of the Human Genome Project. l Compare and contrast patterns of inheritance. l Discuss ethical issues relating to the Human Genome Project.

2. Lecture Terms l DNA l Messenger RNA l Transfer RNA l Ribosomal RNA l Genetic mutations l Genotype l Phenotype l Karyotype l Homozygous l Heterozygous l Polygenic inheritance l Co-dominance l Incomplete dominance l Diploid l Haploid l Gene mapping l Recessive trait l Dominant trait

3. Genetics and Disease l Extrinsic Factors  Infectious agents  Mechanical trauma  Toxins  Radiation  Temperature extremes  Nutrition  Psychological stress l Intrinsic Factors  Age  Sex  Acquired abnormalities  Genome

4. DNA - Deoxyribonucleic acid l All information needed for programming cellular functions is stored in DNA! l DNA = Base + Sugar + Phosphate

5. Duplication of Genetic Code l Transcription  DNA unzips and mRNA formed  Translation  mRNA attaches to ribosomes  tRNA delivers amino acid to ribosomes to form polypeptides

6. Organization of Genetic Code l Codons - sequence of three bases that “switch on and off” other parts of DNA l Mutations - alterationsin sequences of bases  Can result in favorable or unfavorable functions of cell processes  Healthy individuals thought to have at least 3 - 5 mutated genes (generally in heterozygous condition)!

7. Nature of the Genome l Gene - portion of DNA that controls development of a particular trait l Located at a specific position, locus, on a chromosome l One gene inherited from each parent  Except for gametes, each cell possesses two sets of chromosomes (one from father & one from mother) which is called diploid state.  Gametes (sex cells) have undergone meiosis and haveonly one set of chromosomes which is called haploid state.

8. Chromosomal Theory of Inheritance l Dominant vs. Recessive » Genes exist in various chemical states, called alleles. Generally one allele is dominant to other recessive alleles (dominant is expressed; recessive alleles are masked). l Incomplete dominance l Co-dominance l Polygenic inheritance

9. Pattern of Inheritance l Homozygous Individuals that possess same allele on each of their pair of chromosomes are homozygous with respect to a given trait! l Heterozygous Individuals with different alleles on each of their chromosome pairs.

10. Theory of Inheritance l Chromosomes » 22 pairs autosomes » 1 pair sex chromosomes l Karyotype - picture of chromosomes l Genotype - an individual’s unique sequence of bases l Phenotype - recognizeable trait

11. Pattern of Inheritance l Expressivity - expression of a gene in the phenotype; ranges from mild to severe l Penetrance - ability of a gene to express its function l 50% penetrance means that 50% of individuals with a particular genotype will demonstrate a recognizeable phenotype.

12. Human Genome Project l Goal  to map the entire human genetic code  an estimated 50,000 to 100,000 genes  to identify chemical basis of approximately 4000 genetic diseases by year 2005

13. Human Genome Project l Procedure  Gene mapping - assignment of genes to specific chromosomes; earlies efforts used X-linked traits  Markers established by analysis of coinherited disorders  Unit of measurement = centimorgan (cM)  1 cM = separation 1% of time during transmission from parent to child  1 cM - roughly equivalent to 1 million base pairs of DNA

14. Genome Project Issues l Confidentiality! l Diagnosis without hope of cure or treatment! l Current and future discoveries?  Huntington’s chorea  Alzheimer’s disease  Breast cancer

15. How would you answer the following question? l Are most diseases inherited?