Role of Gene Expression

1. CH11 pg217 Role of Gene Expression • DNA on several chromosomes • Only some of these genes are expressed at any given time • Activation of a gene that results in transcription and the production of mRNA.

2. Section 1 Control of Gene Expression Chapter 11 Gene Expression in Eukaryotes • Structure of a Eukaryotic Gene • Eukaryotic genes are organized into; • noncoding sections, introns, • coding sections, exons • Mitosis and Meiosis (Interphase) • Promotor (introns and exons) • Introns are areas that at transcribed only • Exons are transcribed and translated

3. Control of Gene Expression Chapter 11 • Research still being done about the presence of introns and exons • Believe to regulate translation of RNA • Act as a switch

4. Control of Gene Expression Chapter 11 Removal of Introns After Transcription

5. Control of Gene Expression Chapter 11 • Control at the Onset of Transcription • Gene expression can be controlled through regulatory proteins known as transcription factors. • Dictate placement of RNA polymerase • Enhancers

6. Section 1 Control of Gene Expression Chapter 11 Controlling Transcription in Eukaryotes

7. Developmental Genes CH11 pg 225 • Homeotic Genes • Genes that determine where anatomical structures will be placed during development. • For example, appendages • A specific DNA sequence known as thehomeoboxregulates patterns of development. • The homeoboxes of many eukaryotic organisms appear to be very similar.

8. CH12 pg 235 Chromosomes and Inheritance Chromosomes • Genes reside on chromosomes. • Sex Chromosomes and Autosomes • Sex chromosomes determine an organism’s sex (gender). • Chromosomes that do not determine the sex of an individual are called autosomes. • Pg 235 – 238 Discusses other influences on traits that we have covered, please review

9. Chapter 12 Mutations • Germ-cell mutationsoccur in gametes and can be passed on to offspring. • Somatic-cell mutationsoccur in body cells and affect only the individual organism.

10. Section 1 Chromosomes and Inheritance Chapter 12 Mutations, continued • Chromosome Mutations • Chromosome mutationsare changes in the structure of a chromosome or the loss or gain of an entire chromosome.

11. Section 1 Chromosomes and Inheritance Chapter 12 Chromosomal Mutations

12. Section 1 Chromosomes and Inheritance Chapter 12 Mutations, continued • Gene Mutations • Gene mutationsare changes in one or more of the nucleotides in a gene.

13. Section 1 Chromosomes and Inheritance Chapter 12 Gene Mutations

14. Section 2 Human Genetics Chapter 12 Inheritance of Traits • Pedigrees • Geneticists use pedigrees to trace diseases or traits through families. • Pedigrees are diagrams that reveal inheritance patterns of genes.

15. Pedigree for Cystic Fibrosis Chapter 12

16. Human Genetics Chapter 12 Some Important Genetic Disorders

17. Section 2 Human Genetics Chapter 12 Detecting Genetic Disease • Genetic screening examines a person’s genetic makeup and potential risks of passing disorders to offspring. • Amniocentesis and chorionic villi sampling help physicians test a fetus for the presence of genetic disorders.

18. Section 2 Human Genetics Chapter 12 Detecting Genetic Disease, continued • Genetic Counseling • Genetic counseling informs screened individuals about problems that might affect their offspring.

19. Section 2 Human Genetics Chapter 12 Treating Genetic Disease • Genetic disorders are treated in various ways. • Among the treatments are symptom-relieving treatments and symptom-prevention measures, such as insulin injections for diabetes.

20. Section 2 Human Genetics Chapter 12 Treating Genetic Disease, continued • Gene Therapy • In gene therapy, a defective gene is replaced with a copy of a healthy gene. • Somatic cell gene therapy alters only body cells. • Germ cell gene therapy attempts to alter eggs or sperm.