Modern Genetics Table of Contents Human Inheritance Human
Modern Genetics Table of Contents Human Inheritance Human Genetic Disorders Advances in Genetics
Modern Genetics Essential Question How can genetic information be used?
Modern Genetics Lesson 1 Objectives: 1. Identify some patterns of inheritance in humans. 2. Describe the functions of the sex chromosomes.
Modern Genetics Human Inheritance -Many human traits are controlled by a single gene with two alleles: one dominant and one recessive *Examples: widow’s peak, smile dimples, hitch-hikers thumb, curved pinkie.
Modern Genetics -Other human traits are controlled by single genes with multiple alleles. *This means more than two alleles exist for a trait. *However, you still only inherit two alleles *Example: Human Blood Type
Modern Genetics -Three alleles are involved: A, B, and o. -A and B are both dominant (co-dominant) -O is recessive -Blood type A can have genotypes AA or Ao; -Blood type B can have genotypes BB or Bo; -Blood type AB can have only genotype AB -Blood type O can have only genotype oo
Modern Genetics -Finally, a lot of human traits are controlled by many genes that act together. This is called, Polygenic Inheritance. *Examples: eye, skin, and hair color, height, weight, body build, and shape of eyes, lips, and ears.
Modern Genetics Skin Color Graph and Punnett Square
Modern Genetics The Sex Chromosomes One pair of chromosomes determines the sex of an organism. The larger chromosome in the pair is the X chromosome. The smaller is the Y. XY = male X Y X X XX = female
Modern Genetics -Egg cells from a female contain only X chromosomes. -Sperm cells from a male can contain either an X or a Y. So it is the father who determines the sex of the child depending on which sperm cell fertilizes the egg
Modern Genetics - Human Inheritance
Modern Genetics Sex-Linked Traits -The sex chromosomes carry genes that make a person male or female. -They also carry genes that determine other traits. -These traits are usually more common in men because they are carried on the X chromosome. The matching gene on the Y chromosome is missing.
Modern Genetics -They are called Sex-Linked Traits. -Examples: *Color-blindness and Hemophilia
Modern Genetics Punnett Sq. with Sex-Linked Traits Color Blind Male marries a Normal Female Xc Y x XX None of their X X Xc Y X c. X XY Xc X XY kids will be color blind. However, any girl they have will be a carrier.
Modern Genetics Lesson 2 Objectives: 1. Identify two major causes of genetic disorders in humans. 2. Explain how genetic disorders are traced, diagnosed, and treated.
Modern Genetics Human Genetic Disorders -A genetic disorder is an abnormal condition that a person inherits. Information for the disorder is carried on chromosomes just like other genetic information.
Modern Genetics -Examples: *Cystic Fibrosis—genetic disorder in which the body produces too much mucus in the lungs and intestine. It is homozygous recessive. 1/20 Caucasians carry a recessive allele. It is caused by a 3 base deletion in the DNA molecule.
Modern Genetics *Sickle-Cell Anemia—genetic disorder in which red blood cells have an unusual sickle shape. RBC’s can’t carry as much oxygen and can clog arteries. The allele is codominant with the normal so you must have two alleles to produce ONLY sickle-shaped RBC’s. More common in African americans (1/400).
Modern Genetics Sickle-Cell RBC Normal RBC How sickle cells cause blood clots.
Modern Genetics - Human Genetic Disorders Sickle-Cell Disease Click the Video button to watch a movie about sickle-cell disease.
Modern Genetics *Hemophilia—genetic disorder in which blood clots slowly or not at all. It is a homozygous recessive sex linked trait carried on the X chromosome. So it is more common in men than women.
Modern Genetics *Down Syndrome—caused by an extra 21 st chromosome. Results in some degree of mental retardation. Heart defects and other physical conditions are also common. Children with Down Syndrome
Modern Genetics Pedigrees -A pedigree is a chart that tracks which members of a family have a particular trait. -The trait can be an ordinary trait or a genetic disorder.
Modern Genetics These are the symbols used on a Pedigree chart. = female with the trait being studied. = female without the trait being studied. = male without the trait being studied.
Modern Genetics Half-colored figures represent carriers. Horizontal lines represent marriages or matings. Vertical lines represent children or offspring.
Modern Genetics - Human Genetic Disorders
Modern Genetics - Human Genetic Disorders A Hemophilia Pedigree The pedigree shows the inheritance of hemophilia, a sexlinked disorder in a family.
Modern Genetics Lesson 3 Objectives: 1. Describe three ways of producing organisms with desired traits.
Modern Genetics Advances in Genetics -Three genetic techniques allow people to produce organisms with more desirable traits. -They are: Selective breeding, Cloning, Genetic engineering
Modern Genetics - Advances in Genetics Selective Breeding Click the Video button to watch a movie about selective breeding.
Modern Genetics Selective Breeding -Selective Breeding—selecting organisms with desired traits to be parents of the next generation. -Two types:
Modern Genetics *Inbreeding—the crossing of closely related organisms. Self-pollination in plants is an example. Purebred animals are an example. It is a way of keeping desirable traits in a breed.
Modern Genetics Problems: Organisms are too genetically similar and tend to be susceptible to diseases. Inbred animals have difficulty adapting to environmental changes. Certain undesirable traits become common because they form pairs during fertilization.
Modern Genetics Hybridization—the crossing of two genetically different individuals. Results in offspring that have characteristics of both parents. Organisms are more genetically different and are therefore likely to be stronger and healthier than inbred organisms. This is especially true in hybrid plant varieties.
Modern Genetics Problems: Many times the organisms produced are sterile. Examples: Tigon—cross between a female lion and a male tiger. Mule—cross between a donkey and a female horse. Liger—cross between a male lion and a female tiger.
Modern Genetics Just for Fun---Check these out!!! What if you could cross a golden retriever with a bald eagle…
Modern Genetics a great dane and a horse…
Modern Genetics A pug and gorilla…
Modern Genetics a penguin and a housecat…
Modern Genetics a sparrow and a tiger…
Modern Genetics a dachshund an owl…
Modern Genetics an orangutan and a mutt…
Modern Genetics or a ram, a gorilla and a German Shepherd?
Modern Genetics Cloning Clone —an individual that is genetically identical to and has only one parent.
Modern Genetics Cloning -Cloning plants is easy and has been done for many years. -Just take a cutting from a stem, give it water until it sprouts roots, then plant it. You have a clone of the first plant.
Modern Genetics -Another technique is called vegetative propagation. Here you take branches from one plant and graft them onto other plants. -Many seedless fruits are grown this way.
Modern Genetics Animal Cloning -The first successfully cloned animal was a tadpole, cloned in 1952. It was cloned from embryonic cells.
Modern Genetics -In February 1997, Ian Wilmut, a Scottish scientist, successfully cloned an adult sheep. *The sheep’s name was Dolly. *Dolly was cloned from a mammary cell taken from her mother. She was the only lamb to Dolly was the first animal survive from 277 eggs. cloned from an adult animal.
Modern Genetics In sexual reproduction, a child gets half its genes from its mother (in her egg) and half from its father (in his sperm cell). Cloning is a type of asexual reproduction. All the child’s genes would come from a body cell of a single individual.
Modern Genetics In order for the embryo to develop, the reconstructed egg must be treated with chemicals or electric current to get the cells to divide.
Modern Genetics Two types of Cloning : Reproductive and Therapeutic -Reproductive Cloning produces an embryo which is implanted into a female’s womb with the intent to produce a fully formed offspring *Dolly was produced this way. (Dolly was put down on Feb. 14, 2003. She suffered from lung cancer and crippling arthritis. She was 6 yrs old. Most Finn Dorset sheep live to be 11 -12 yrs. old).
Modern Genetics -Other successfully cloned mammals include: goats, cows, mice, pigs, cats, rabbits and a gaur. -Attempts to clone other species such as *monkeys, chickens, horses, and *dogs have been unsuccessful
Modern Genetics Therapeutic Cloning is the production of embryos for use in research. The cloned embryos are not placed in a female to be carried to term, but are used to generate stem cells which can then create tissues and organs.
Modern Genetics -This cloning uses the nucleus of a body cell to grow new skin, nerve, or muscle cells—or any type of cell needed. -These cells will be genetically identical to the other cells, so the body will not reject them. -This would improve the success of transplant surgeries. -Researchers also believe that one day stem cells can be used as replacement cells to treat heart disease, Alzheimer’s, cancer, and other diseases.
Modern Genetics Risks of Cloning -Reproductive Cloning *Expensive *Highly inefficient (90% of cloning attempts fail) *Cloned animals seem to be less healthy *May be premature aging problems
Modern Genetics *Therapeutic Cloning -Ethical concerns about harvesting and terminating human embryos. -May lead to “designer babies”
Modern Genetics Genetic Engineering -In genetic engineering, genes from one organism are transferred into the DNA of another organism. -This process can be used to produce medicines (like insulin), to improve food crops, and in gene therapy (to cure people of genetic diseases).
Modern Genetics The Human Genome Project -Began in 1985. -First draft is complete.
Modern Genetics -A genome is all the DNA in one cell of one organism. -Project goal—to identify the DNA sequence of every gene in the human genome.
Modern Genetics DNA Fingerprinting -This technique was developed in 1984 by Professor Sir Alec Jeffreys of England. -It is used to identify people and show whether people are related. -Unless you are an identical twin, your DNA is unique.
Modern Genetics - Human Inheritance Colorblindness Punnett Square
Modern Genetics - Human Inheritance of Blood Type Blood type is determined by a single gene with three alleles. This chart shows which combinations of alleles result in each blood type.
Modern Genetics - Human Inheritance Identifying Main Ideas As you read the section “Patterns of Human Inheritance, ” write the main idea in a graphic organizer. Then write three supporting details that further explain the main idea. Main Idea Human traits are controlled by single genes with two alleles, single genes with multiple alleles, and multiple genes. Detail Human traits controlled by single genes with two alleles have two distinctly different phenotypes. Though a single gene can have multiple alleles, a person carry only two of these alleles. Multiple genes that control a trait act together to produce a single trait with a large number of phenotypes.
Modern Genetics - Human Inheritance Links on Genetics Click the Sci. Links button for links on genetics.
Modern Genetics End of Section: Human Inheritance
Modern Genetics - Human Genetic Disorders Pedigree Activity Click the Active Art button to open a browser window and access Active Art about pedigrees.
Modern Genetics - Human Genetic Disorders Comparing and Contrasting As you read, compare and contrast the types of genetic disorders by completing a table like the one below. Disorder Cystic fibrosis Sickle-cell disease Description Body produces abnormally thick mucus. Red blood cells are sickle -shaped and have reduced ability to hold oxygen. Cause Recessive allele due to removal of three DNA bases Codominant allele Hemophilia Blood clots slowly or not at all. Recessive allele on X chromosome Down Syndrome Mental retardation and heart defects An extra copy of chromosome 21
Modern Genetics End of Section: Human Genetic Disorders
Modern Genetics - Advances in Genetics Changing Rice Production The graph shows how worldwide rice production changed between 1965 and 2000. New, hybrid varieties of rice plants are one factor that has affected the amount of rice produced.
Modern Genetics - Advances in Genetics Changing Rice Production Reading Graphs: According to the graph, how did rice production change between 1965 and 2000? Rice production increased.
Modern Genetics - Advances in Genetics Changing Rice Production Reading Graphs: How many metric tons of rice per hectare were produced in 1965? How many were produced in 2000? 2 in 1965; 4 in 2000
Modern Genetics - Advances in Genetics Changing Rice Production Calculating: Calculate the approximate difference between rice production in 1965 and 2000. 2 metric tons/hectare
Modern Genetics - Advances in Genetics Changing Rice Production Developing Hypotheses: What factors besides new varieties of plants might help account for the difference in rice production between 1965 and 2000? Possible answer: fertilizers and improved harvesting methods
Modern Genetics - Advances in Genetics Genetic Engineering Scientists use genetic engineering to create bacterial cells that produce important human proteins such as insulin.
Modern Genetics - Advances in Genetics Asking Questions Before you read, preview the red headings. In a graphic organizer like the one below, ask a question for each heading. As you read, write answers to your questions. Questions What is selective breeding? Answers Selective breeding is the process of selecting organisms with desired traits to be parents of the next generation. Why are organisms cloned? To produce offspring with desired traits What is genetic engineering? A process in which genes from one organism are transferred into the DNA of another organism What advance has helped us learn about human genetics? The Human Genome Project
Modern Genetics - Advances in Genetics Links on Genetic Engineering Click the Sci. Links button for links on genetic engineering.
Modern Genetics End of Section: Advances in Genetics
Modern Genetics Graphic Organizer Human traits controlled by Single genes Multiple alleles Many genes Sex-linked genes such as Widow's peak Blood type Height Colorblindness
Modern Genetics End of Section: Graphic Organizer
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