Exam 13: Genes, Chromosomes, and Human Genetics

Genetic map units represent ____.

When one parental allele is expressed and the other is silenced, the phenomenon is called ____.

Recombination frequency is ____.

Individuals with extra or missing copies of one or more chromosomes are called ____.

Sex-linked genes are ____.

If a hypothetical human female of genotype XX had no Barr body in any of her cells, ---____.

Suppose that in studies of genes on the same chromosome you find the following recombination frequencies: Figure 13.2 Why is the total distance between a and b less than the distance between a and c plus the distance between c and b ?

In Drosophila melanogaster, the gene for eye color is located on the X chromosome. The allele for red eye color (X^w+) is dominant over the allele for white eye color (X^w). You examine a vial of 100 flies that are all offspring from a single genetic cross. You find only red-eyed females and red-eyed males present. Flies from the vial were allowed to interbreed, and in the next generation you find only red-eyed females, but you find both red-eyed and white-eyed males. The genotypes of the original parents were ____.

In Drosophila melanogaster, the allele for long wings is dominant over the allele for vestigial wings, and the allele for a gray body is dominant over the allele for a black body. A testcross was done to check for genetic linkage between the genes for these traits, with the following results for the offspring: 410 flies with long wings and a gray body 105 flies with long wings and a black body 390 flies with vestigial wings and a black body 95 flies with vestigial wings and a gray body Which of the choices below best represents the map distance between the genes for these two traits?

Prenatal diagnosis techniques, such as amniocentesis and chorionic villus sampling, remove cells produced by the embryo. These cells are then used ____.

In humans, males are the ____ sex, and females are the ____ sex.

Figure 13.7 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?

A recombinant phenotype is ____.

In Drosophila melanogaster, the gene for eye color is located on the X chromosome. The allele for red eye color (X^w+) is dominant over the allele for white eye color (X^w). You examine a vial of 100 flies that are all offspring from a single genetic cross. You see only red-eyed females and white-eyed males present. The genotypes of the parents were ____.

Figure 13.4 The change in the chromosome depicted between the top and the bottom in the accompanying figure represents a(n) ____.

About 4% of individuals of Northern European descent are carriers for ____, an autosomal recessive genetic disorder in which a defective membrane transport protein leads to deficient chloride levels in extracellular fluids.

Nondisjunction refers to the ____.

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 man has an X-linked recessive form of hemophilia, but the woman does not. Genetic tests reveal the woman is not a carrier for hemophilia. How should you advise them?

Why are mitochondrial genes inherited in a non-Mendelian pattern?

Progeria is a genetic condition that causes ____.