A color-blind woman mates with a male with normal color vision. Which of these results would indicate that color blindness is caused by an X-linked recessive allele?
All of the sons, and none of the daughters, are color-blind.
Color blindness is an X-linked recessive trait. A color-blind man has a daughter with normal color vision. What is the genotype of the daughter?
Color blindness is an X-linked recessive trait. A color-blind man has a daughter with normal color vision. She mates with a male who has normal color vision. What is the expected phenotypic ratio of their offspring?
2 normal vision females : 1 normal vision male : 1 color-blind male
Color blindness is an X-linked recessive trait. A color-blind man has a daughter with normal color vision. She mates with a color-blind male. What is the expected phenotypic ratio of their offspring?
1 normal vision female : 1 color-blind female : 1 normal male : 1 color-blind male
Color blindness is an X-linked recessive trait. A color-blind woman mates with a male with normal color vision. What is the expected phenotypic ratio of their offspring?
1 normal vision daughter : 1 color-blind son
2 normal vision
Mendel's Principle of Segregation can be visualized when we observe _____.
Homologous chromosomes separating during Meiosis I.
A white-eyed female Drosophila is crossed with a red-eyed male Drosophila. Which statement below correctly describes the results?
None of the females will have white eyes
In humans, the _____ determines the sex of the offspring because _____.
male gamete ... each male gamete can contribute either an X or a Y chromosome
In general, the frequency with which crossing over occurs between two linked genes depends on _____.
How far apart they are on the chromosome
A situation in which chromosome number can be represented as either 2n+1 or 2n-1 is called_____.
True or False: An aneuploid individual has either too many or too few chromosomes, usually as a result of non-disjunction.
If a fragment of a chromosome breaks off and then reattaches to the original chromosome at the same place but in the reverse direction, the resulting chromosomal abnormality is called _____.
A particular allele will either be expressed or silenced, depending on whether it is inherited from a male rather than a female. This phenomenon is known as _____.
What is a nondisjunction?
An error in cell division that causes homologous chromosomes or sister chromatids to move to the same side of the dividing cell
When can nondisjunction occur?
In meiosis, when homologous chromosomes fail to separate
In mitosis, when sister chromatids fail to separate
In meiosis, when sister chromatids fail to separate
What kind of cell results when a diploid and a haploid gamete fuse during fertilization?
A triploid cell
Of the following chromosomal abnormalities, which type is most likely to be viable in humans?
If a diploid cell undergoes meiosis and produces two gametes that are normal, and one with n − 1 chromosomes, and one with n + 1 chromosomes, what type of error occurred?
A nondisjunction error occurred in meiosis II, in which both sister chromatids of a chromosome migrated to the same pole of the cell.
If a diploid cell undergoes meiosis and produces two gametes with n + 1 chromosomes and two gametes with n− 1 chromosomes, what type of error occurred?
A nondisjunction error occurred in meiosis I, in which both members of a homologous pair migrated to the same pole of the cell.
Humans are diploid and have 46 chromosomes (or two sets). How many sets of chromosomes are found in each human gamete?
A particular diploid plant species has 48 chromosomes, or two sets. A mutation occurs and gametes with 48 chromosomes are produced. If self-fertilization occurs, the zygote will have _____ set(s) of chromosomes.
Determine the sequence of genes along a chromosome based on the following recombination frequencies: A - B, 8 map units; A - C, 28 map units; A - D, 25 map units; B - C, 20 map units; B - D, 33 map units.
D - A - B - C
Imagine a human disorder that is inherited as a dominant, X-linked trait. How would the frequency of this disorder vary between males and females?
Females would display this disorder with greater frequency than males
Which of these descriptions of the behavior of chromosomes during meiosis explains Mendel's law of segregation?
The two alleles for each gene separate as homologous chromosomes move apart during anaphase I.