Exam 29: Genetics and Human Inheritance

Which genetic condition can be described as the inheritance of the heterozygous phenotype, which is expressed as an intermediate between the dominant and recessive alleles?

A cardiac researcher is trying to determine whether a pattern of very high blood cholesterol is genetic in a group of Pennsylvania Dutch. Therefore, the scientist looks through years of medical records plus patterns of marriage through several generations. The investigator is doing a type of hereditary research called ________.

________ traits involve the expression of certain autosomal genes that are not located on the sex chromosomes but that are powerfully influenced by the presence of sex hormones, so that the expression of these genes differs between males and females.

Duffy factor is due to a chemical that occurs on the membranes of red blood cells and is sometimes used as a blood-typing attribute in the same way that ABO and Rh factor blood types are used. Recent research has found that people with Duffy factor are about 40% less likely to be infected with HIV, given similar circumstances. Given that HIV affects white blood cells, how would you characterize the Duffy factor gene, and why?

An individual with the genotype AaBbCC will produce gametes with which possible assortment of genes?

The gene for Tay-Sachs disease codes for a nonfunctional form of the enzyme hexosaminidase A (or Hex A ) It has been found that a person with only one-third the maximum amount of Hex A can function absolutely normally. Please characterize the heredity of Tay-Sachs disease.

Match each definition to the correct term -A situation in which both alleles for a certain trait produce functional proteins.

When one gene causes multiple effects, the condition is called ________.

Gene testing allows the parents to learn more about their child in the prenatal period. However, there are genetic disorders, such as Huntington's disease, that show no phenotypic signs until age 35. This disease is caused by a dominant allele, resulting in degeneration of the brain, muscle spasms, and death within a decade or two. Because it is caused by a dominant allele, 50% of the offspring will carry the disease. If you knew that someone in your family had Huntington's disease, would you get tested early on, before you start a family and have your own children? Would you rather not know your fate, even if it means that you may pass the dominant allele of this disease to your offspring? (Note: Before being tested, a person usually undergoes a battery of psychological tests to make sure that he or she is emotionally stable enough to deal with knowing that he or she will develop the disease and that there is no cure.)

Match each definition to the correct term -The alteration of a chromosome that involves the addition of a piece of chromosome.

Match each definition to the correct term -A condition in which someone has different alleles for the same gene.

PKU is a hereditary condition that appears only if a person has two copies of the gene. Therefore, the gene is ________.

A pedigree is useful because it ________.

If Hani has type A blood and his mother has type B blood, which of the following is the most likely genotype of Hani's father?

If your parents are heterozygous for a gene, what is the chance that you will have at least one copy of it?

Babies were accidentally switched at the hospital! Mr. and Mrs. Fire both have type O blood. Which of the following four babies of the same age is most likely the Fire child?

Duplication can be advantageous for evolution. While the correctly functioning DNA segment remains intact, duplication provides new copies of genes that can be altered to new functions. Unfortunately, duplication can also result in human genetic disorders. Please provide an example of a human genetic disorder that occurs when certain DNA sequences are duplicated.

Adel has freckles, autosomal dominant. What is her genotype?

In a family, both parents have freckles and widow's peak. Both of these traits are dominant: F = freckles, W = widow's peak. They have a child who has no widow's peak and no freckles. Which one is a possible dihybrid genotype of the child?

An autosomal recessive disorder in which a young person produces thick mucus and excessively salty sweat and has serious respiratory problems is ________.