State Standard 2C. Using Mendel’s laws, explain the role of meiosis in reproductive variability. 2D. Describe the relationships between changes in DNA and potential appearance of new traits Dominant & Recessive Genetic Disorders (11.1)

11.1 Basic Patterns of Human Inheritance Complex Inheritance and Human Heredity Chapter 11 Recessive Genetic Disorders  A recessive trait is expressed when the individual is homozygous recessive for the trait.  A person who is heterozygous is called a carrier.

Complex Inheritance and Human Heredity Cystic Fibrosis (Recessive)  Common among caucasians  Affects the mucus-producing glands, digestive enzymes, and sweat glands  Chloride ions are not absorbed into the cells of a person with cystic fibrosis but are excreted in the sweat.  Without sufficient chloride ions in the cells, a thick mucus is secreted.  Treatment includes physical therapy, medication, & special diets Basic Patterns of Human Inheritance Chapter 11

A normal woman marries a man with cystic fibrosis. If they have children, what ratio will be totally normal? Explain.

Complex Inheritance and Human Heredity Albinism (Recessive)  Caused by altered genes, resulting in the absence of the skin pigment melanin in hair, skin, and eyes  White hair  Very pale skin  Pink pupils  Sun’s ultraviolet radiation is especially dangerous 11.1 Basic Patterns of Human Inheritance Chapter 11

Complex Inheritance and Human Heredity Albinism (Recessive) 11.1 Basic Patterns of Human Inheritance Chapter 11

An albino man marries a woman who is a carrier. Create a Punnett Square to show the possibilities of their offspring. Include genotypic & phenotypic ratios.

Complex Inheritance and Human Heredity Tay-Sachs Disease (Recessive)  Recessive disorder on chromosome 15  Caused by the absence of the enzymes responsible for breaking down fatty acids called gangliosides  Gangliosides accumulate in the brain, inflating brain nerve cells and causing mental deterioration.  Occurs predominantly in Jews of Eastern European descent Basic Patterns of Human Inheritance Chapter 11

A man & woman who are both Tay Sachs carriers get married & decide to have children. What percent chance is there of them having a purebred normal baby? Use a Punnett Square to determine your answer.

Complex Inheritance and Human Heredity Galactosemia (Recessive)  Recessive genetic disorder characterized by the inability of the body to digest galactose.  These people must avoid milk products.  Milk products will cause numerous complications, including mental disability Basic Patterns of Human Inheritance Chapter 11

Complex Inheritance and Human Heredity Dominant Genetic Disorders  Because these disorders are caused by a dominant allele, they affect people who are homozygous dominant and people who are heterozygous Basic Patterns of Human Inheritance Chapter 11

Complex Inheritance and Human Heredity Huntington’s Disease (Dominant)  Huntington’s disease affects the nervous system.  Occurs in 1 in 10,000 humans.  Symptoms first appear between the ages of 30 & 50.  Symptoms include loss of brain function, uncontrollable movements, and emotional disturbances Basic Patterns of Human Inheritance Chapter 11

Complex Inheritance and Human Heredity Huntington’s Disease (Dominant) 11.1 Basic Patterns of Human Inheritance Chapter 11

A woman who is hybrid for Huntington’s marries a man who is normal. What will be the genotypic & phenotypic ratios of their children?

Complex Inheritance and Human Heredity Achondroplasia (Dominant)  Achondroplasia is a genetic condition that causes small body size and limbs that are comparatively short.  Most common form of dwarfism.  Adult height of about four feet.  Normal life expectancy Basic Patterns of Human Inheritance Chapter 11

A man & woman who are both heterozygous for Achondroplasia have children. Can they have a normal child? Explain

Complex Inheritance and Human Heredity Chapter 11

Complex Inheritance and Human Heredity Pedigree  A diagram that traces the inheritance of a particular trait through several generations 11.1 Basic Patterns of Human Inheritance Chapter 11

Label each part of the diagram below

On your first day interning in the office of a human geneticist, a man with purple ears walks in. You questioned the man and wrote down the following family history. The man's mother and one of his sisters also had purple ears, but his father, his brother, and two other sisters had normal ears. The man and his normal- eared wife had seven children, including four boys and three girls. Two girls and two boys had purple ears. Draw the family pedigree and indicate what form of inheritance that the purple-ear trait most likely follows. (Is it dominant or a recessive passed trait?) Pedigree Challenge

Complex Inheritance and Human Heredity Inferring Genotypes  Knowing physical traits can determine what genes an individual is most likely to have. Predicting Disorders  Record keeping helps scientists use pedigree analysis to study inheritance patterns, determine phenotypes, and ascertain genotypes Basic Patterns of Human Inheritance Chapter 11

1.A 2.B 3.C 4.D CDQ 1 A. albinism B. cystic fibrosis C. galactosemia D. Tay-Sachs Identify the disease characterized by the absence of melanin. Complex Inheritance and Human Heredity Chapter 11 Chapter Diagnostic Questions

1.A 2.B 3.C 4.D CDQ 2 Complex Inheritance and Human Heredity Chapter 11 Chapter Diagnostic Questions A. excessive mucus production B. an enlarged liver C. a cherry-red spot on the back of the eye D. vision problems An individual with Tay-Sachs disease would be identified by which symptom?

1.A 2.B 3.C 4.D CDQ 3 Complex Inheritance and Human Heredity Chapter 11 Chapter Diagnostic Questions Under what circumstances will a recessive trait be expressed? A. A recessive allele is passed on by both parents. B. One parent passes on the recessive allele. C. The individual is heterozygous for the trait. D. There is a mutation in the dominant gene.

1.A 2.B 3.C 4.D FQ 2 Complex Inheritance and Human Heredity Chapter 11 A. DD B. Dd C. dd D. dE Which is the genotype of a person who is a carrier for a recessive genetic disorder? 11.1 Formative Questions

1.A 2.B 3.C 4.D FQ 3 Complex Inheritance and Human Heredity Chapter Formative Questions A. at least one parent is a carrier B. both parents are carriers C. both parents are homozygous recessive D. at least one parent is homozygous dominant Albinism is a recessive condition. If an albino squirrel is born to parents that both have normal fur color, what can you conclude about the genotype of the parents?

1.A 2.B 3.C 4.D FQ 4 Complex Inheritance and Human Heredity Chapter 11 A. dosage compensation B. incomplete dominance C. multiple alleles D. sex-linked When a homozygous male animal with black fur is crossed with a homozygous female with white fur, they have offspring with gray fur. What type of inheritance does this represent? 11.2 Formative Questions

1.A 2.B 3.C 4.D FQ 5 Complex Inheritance and Human Heredity Chapter Formative Questions A. autosomes B. Barr bodies C. monosomes D. sex chromosomes Of the 23 pairs of chromosomes in human cells, one pair is the _______.

1.A 2.B 3.C 4.D CAQ 1 Complex Inheritance and Human Heredity Chapter 11 A. 1 and 2 are siblings B. 1 and 2 are parents C. 1 and 2 are offspring D. 1 and 2 are carriers Use the figure to describe what the top horizontal line between numbers 1 and 2 indicates. Chapter Assessment Questions

1.A 2.B 3.C STP 1 Complex Inheritance and Human Heredity Chapter 11 A. heterozygous B. homozygous dominant C. homozygous recessive If a genetic disorder is caused by a dominant allele, what is the genotype of those who do not have the disorder? Standardized Test Practice

1.A 2.B 3.C STP 2 Complex Inheritance and Human Heredity Chapter 11 Standardized Test Practice A. RR B. Rr C. rr Analyze this pedigree showing the inheritance of a dominant genetic disorder. Which would be the genotype of the first generation father?