Exam 13: Genes, Chromosomes, and Human Genetics

Which condition would most likely lead to an apparently normal human female?

Suppose that you have discovered a new mutant in Drosophila melanogaster . The trait is known to be sex linked. Which crosses should you perform to determine if the mutant trait is recessive or dominant?

2014 Examine the pedigree in the accompanying figure. Individuals affected by the genetic condition in question are indicated by filled squares or circles. Which inheritance pattern is most likely correct for this condition in this family?

About 10-15% of African Americans in the US are carriers for ____, an autosomal recessive genetic disorder in which a defective version of the hemoglobin protein is produced.

Which statement correctly describes the inheritance of sex chromosomes?

You are a genetic counselor, and a couple comes to you with concerns that if they have a child together, he or she could have hemophilia. The woman has an X-linked recessive form of hemophilia, but the man does not. How should you advise them?

This autosomal dominant genetic trait is associated with a gene on human chromosome 4 and causes a type of dwarfing due to defective cartilage formation.

Carriers of the sickle-cell allele have a genetic advantage because they have ____.

2014 Examine the pedigree in the accompanying figure. Individuals affected by the genetic condition in question are indicated by filled squares or circles. Which inheritance pattern is most likely correct for this condition in this family?

As an undergraduate research assistant, you are given a genetic mapping project. You are told that genes a and b are 7.4 map units from each other and that genes b and c are 5.7 map units from each other. You perform a testcross to determine the map distance between a and c . Which of the following results would indicate that c lies between a and b ?

A woman with normal blood clotting mates with a man who also has normal blood clotting. Their first child is a boy who has hemophilia. Tests show that the child's hemophilia is X-linked and that he has normal genetic inheritance. You can predict that if the couple has more children together, then it is likely that ____.

The X chromosome ____.

Genetic studies of an animal show that eye color is controlled by an autosomal gene with the dominant allele ( R ) for red eye color and the recessive allele ( r ) for yellow eye color. A second autosomal gene has the dominant allele ( T ) for paws with thumbs and the recessive allele ( t ) for paws without thumbs. The genetic cross RRTT x rrtt creates offspring with genotype RrTt . One of those dihybrids is mated in a testcross ( RrTt x rrtt ). If the two genes are completely linked (no recombination occurs between them), then the testcross should produce offspring with the phenotype ratio ____.

In humans, an extra copy of chromosome 21 typically leads to moderate to severe mental retardation and sterility, as well as to a greater likelihood of heart defects and other problems. This disorder is known as ____.

Your cousin learns that she is a carrier for phenylketonuria (PKU). Her husband's biological mother has PKU. She asks you to explain what this could mean if she and her husband have children and asks what, if anything, could be done to best protect any child that may have. What would you tell her?

The product of the ABL gene is a ______.

Recombination frequency for two genes is a function of the ____.

In humans, sex determination generally depends upon the ____.

Which process exchanges alleles between homologous chromosomes?

The presence of genes that encode many types of hemoglobin in mammals, but not in other vertebrates that evolved earlier, is evidence of ____ of genetic material.