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Pseudohypertrophic muscular dystrophy is an inherited disorder that causes gradual deterioration of the muscles. It is seen almost exclusively in boys born to apparently unaffected parents and usually results in death in the early teens. Is this disorder caused by a dominant or a recessive allele? Is its inheritance sex-linked or autosomal? How do you know? Explain why this disorder is almost never seen in girls.
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- Hereditary hemochromatosis is an autosomal recessive genetic disorder that causes the body to absorb too much iron from the diet. This excess iron is stored in the body's tissues and organs, particularly the skin, heart, liver, pancreas, and joints. Because humans cannot increase the excretion of iron, excess iron can overload and eventually damage tissues and organs. Some individuals who are homozygous for this autosomal recessive gene experience only skin discoloration and joint pain, others experience heart disease in addition to the skin discoloration, still other individuals suffer also suffer from diabetes, severe heart disease, and liver damage. Name and define this genetic phenomenon and explain how it relates to this specific genetic situation described above.arrow_forwardOne form of the bleeding disorder known as von Willebrand disease is an autosomal recessive disease. A man who is a carrier marries a woman who is also a carrier of the disease. (a) What percentage of their children are likely to have a disease phenotype? (b) What percentage of their children are likely to have a normal phenotype? (c) What percentage of their children are likely to be carriers of the disease?arrow_forwardPseudohypertrophic muscular dystrophy is an inheriteddisorder that causes gradual deterioration of the muscles. It isseen almost exclusively in boys born to apparently unaffectedparents and usually results in death in the early teens. Isthis disorder caused by a dominant or a recessive allele?Is its inheritance sex-linked or autosomal? How do youknow? Explain why this disorder is almost never seen in girls.arrow_forward
- Color-blindness (c) is a sex-linked recessive trait, while normal color vision (C) is dominant: If two normal-visioned parents have a color-blind son, what are the parent's genotypes? ~What are the chances that their children will be color-blind?arrow_forwardWhich genotype is indicative of the carriers of a trait associated with an autosomal recessive inheritance pattern? Tt TT tt All of thesearrow_forwardFor a recessive condition, two normal heterozygous individuals have children. What is the likelihood of their children being affected by this condition? What is the likelihood of their children being carriers without the condition? What is the likelihood of their asymptomatic children being carriers? Suppose that an individual with the condition has children with a heterozygous individual, what is the likelihood of their children being carriers?arrow_forward
- Assume for a moment that a child has a autosomal recessive disorder, but both parents appear normal. What is the genotype of both parents? : one parent must be homozygous dominant : both parents must be homozygous recessive : both parents are heterozygous : both parents nust be homozygous dominantarrow_forwardAlbinism is a recessive disorder where there is a lack of melanin. Andrea and her husband Claude both have normal skin pigmentation. Andrea’s mother has the albino phenotype, but her father and her brother do not (normal pigmentation). Claude’s parents are both normal, but he has a sister who has the condition (is albino). Answer the following questions If Andrea and Claude are carriers for the albino allele, what is the probability that they have an albino child? If Andrea and Claude have a second child, what is the probability this child be normal (non-albino)? NOTE: Draw a punnet square or show your work.arrow_forwardA young couple went to see a genetic counselor because each had a sibling affected with cystic fibrosis. (Cystic fibrosis is a recessive disease and neither member of the couple nor any of their four parents is affected). What is the probability that the female of this couple is a carrier and what are the chances that their child will be affected with cystic fibrosis?arrow_forward
- Both have a genetic disorder, but they already have one child who does not have the disorder. They would like to have more children and were told by a friend that since their first child was normal their future children would be normal as well. Explain to them the probability of future offspring being normal or having the disease (assume that this is an autosomal disease). Be sure to tell them whether the disease is brought about by a dominant or recessive allele and what fraction of their children (if any) could be carriers for the disease.arrow_forwardEpilepsy is a central nervous system (neurological) disorder in which brain activity becomes abnormal, causing seizures or periods of unusual behavior, sensations and sometimes loss of awareness. For epilepsy, the concordance values are 72% for monozygotic twins and 15% for dizygotic twins. 1) Is this a single gene inheritance or multifactorial disease? 2) Is there a strong genetic or environmental cause to the development of this disease? If both genetic and environmental causes are implicated, you have to indicate each of them separately.arrow_forwardWhat is nondisjunction? Why does it cause chromosomal abnormalities? What is aneulploidy? Trisomy? Monosomy? Which kind of monosomy always results in miscarriage in early pregnancy? What do these terms mean: genotype, phenotype, allele, homozygous, heterozygous? Be able to recognize single gene inheritance patterns [autosomal dominant, autosomal recessive, X linked recessive] from a pedigree. Also, how are simple Mendelian traits transmitted? What genotype produces the phenotype? Why do some inheritance patterns result in many more males than females showing the phenotype? What inheritance patterns do Huntington disease and sickle cell anemia, and hemophilia follow (autosomal dominant or autosomal recessive, or X-linked recessive)? What are some of the symptoms of these diseases?arrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage LearningBiology (MindTap Course List)BiologyISBN:9781337392938Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. BergPublisher:Cengage Learning