Genetic Changes Life Science Chapter 8

Mutations Mutation – any change in an organism’s genetic material Almost always harmful. Usually occurs randomly. Single base pair exchange for another Can involve a whole chromosome, or set of chromosomes. Lethal mutation – a mutation that causes death

Gene Mutation Gene Mutation – a change in the sequence of bases in a gene; directly affects the protein formation Some mutations have more of an effect than others Eye-color gene mutates in a finger cell, probably no affect. Skin cell affecting color – might produce spot in skin Skin cell with lethal gene mutation

Gene Mutations Somatic mutations – occur in cells that do not make gametes (body cells) Not passed on to future generations Germ mutations – occur in gametes or cells that form gametes May not affect organism but can be passed on to the offspring and affect them Mostly recessive

Chromosomal Mutations Chromosomal Mutation – involves the number of chromosomes or the number of genes or location of genes on a chromosome Does not directly affect the protein formation May cause an organism to have some different traits Down’s syndrome – three 21st chromosomes

Human Mutation Disorders Hemophilia Known as “bleeders disease” Sex-linked, more prominent in males, females can be carriers Missing blood clotting chemical

Human Mutation Disorders Duchenne Muscular Dystrophy Sex-linked Muscle deterioration Muscles enlarge and swell, then shrink and waste away

Human Mutation Disorders Cystic Fibrosis Recessive trait disorder Thick mucous that blocks glands and pores; causes thick, sticky mucus. Severely affects the lungs, usually cause of death

Human Mutation Disorders Tay-Sachs Lack enzyme that breaks down fatty substances. Fatty substances build up in nervous system and cause death of neurons; blindness, seizures, paralysis, finally death usually by age 5.

Human Mutation Disorders Malignant Hyperthermia Dominant gene mutation Mostly discovered when someone has general anesthesia (are put to sleep for surgery) Triggers sudden high blood pressure and extremely high body temperature

Human Mutation Disorders Achondroplasia Dominant gene mutation Causes long bones in arms and legs to stop growing prematurely Normal size head and body with short arms and legs Most dwarfs have this.

Applied Genetics Selective Breeding – man chooses organisms with desirable traits and breeds them with the hope that the offspring will carry the desired traits Inbreeding – mating of an organism with it’s close relative Ex. Pink roses, short-legged sheep, Labradoodles

Applied Genetics Crossbreeding (hybridization) – breeding individual traits from different varieties to produce offspring that have the traits of both parents Ex. Breeding wheat that resists certain fungal diseases, with a wheat that survives cold temperature. Offspring, called Marquis wheat, has both traits. Genetic Engineering – the use special techniques to control the genetic makeup of an organism

Clones Clone- group of genetically identical organisms that were produced by sexual reproduction. Cloning- ethical dilemmas

Twins Identical – result of a single sperm and ovum uniting. Technically clones Fraternal- result of two sperm and two ovum uniting separately. Not the same genetic makeup.

Human Genetic Engineering Man is made in God’s image We have the God-given ability to learn, gain knowledge, and direct our lives. We must use knowledge wisely.