CH 11 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.

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

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

Chapter 11 Removal of Introns After Transcription 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

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

Developmental Genes CH 11 pg 225 Homeotic Genes –Genes that determine where anatomical structures will be placed during development. –For example, appendages –A specific DNA sequence known as the homeobox regulates patterns of development. –The homeoboxes of many eukaryotic organisms appear to be very similar.

CH 12 pg 235 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 Chromosomes and Inheritance

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

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

Chapter 12 Chromosomal Mutations Section 1 Chromosomes and Inheritance

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

Chapter 12 Gene Mutations Section 1 Chromosomes and Inheritance

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.

Chapter 12 Pedigree for Cystic Fibrosis

Chapter 12 Some Important Genetic Disorders Human Genetics

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.

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

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.

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.