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1

Genes located along the X chromosome:

are called X-linked genes.

2

During meiosis in the male, sex chromosomes segregate to produce two types of sperm: X-bearing sperm and Y-bearing sperm.

true

3

The group represented by a large proportion of the progeny, deriving from maternal gametes containing alleles present in the same combinations as found in the mother's X chromosomes, is called the ______________________ group.

nonrecombinant

4

Which of the following statements regarding sex ratios are true?

Sex ratios are dynamic and can change over time; the ratio of males to females at birth may be different from that during adolescence and adulthood.

5

A woman is at the train station and sees a family with five boys. The occurrence of five boys in this family is likely the result of a mutation in one of the X chromosomes of the mother that impacts the survival of female embryos in the womb.

false

6

Which one of the following statements does not accurately describe segregation of the sex chromosomes?

In humans, the sex at each birth is not a random process because there are often large families with either all girls or all boys.

7

Sons of a cross between a white-eyed male and a red-eyed female always have red eyes.

false

8

The group that represents a small proportion of the progeny, deriving from maternal gametes containing combinations of alleles not found in either X chromosome of the mother, is called the _______________ group.

recombinant

9

Which of the following events occur during anaphase I of meiosis?

In males, the X chromosome is segregated from the Y chromosome.

10

Nondisjunction could be the reason for a red-eyed male offspring from a cross between a red-eyed male and a white-eyed female.

true

11

Why are the female progeny from the F1 cross shown in Figure 17.9 not used for linkage analysis?

All F2 females have a wild-type phenotype of red eyes and cross-veined wings.

12

During meiosis in the female, sex chromosomes segregate to produce two types of eggs: X-bearing eggs and Y-bearing eggs.

false

13

Which of the following statements explains why all of the F1 females from a cross between a red-eyed homozygous female and a white-eyed male are heterozygous?

The male parent provides them with a white-eye allele on the X, and the female parent provides them with a red-eye allele on the X.

14

Daughters of a cross between a white-eyed male and a red-eyed female always have red eyes.

false

15

What kind of eye color would be expressed in male progeny from a white-eyed female and a red-eyed male?

All males would have white eyes.

16

Most chromosomes are paired and are both inherited from either the mother or the father.

false

17

Which of the following statements regarding both the X and Y chromosomes are true?

All organisms on Earth―whether insects, birds, mammals, etc.―have both X and Y chromosomes.
If an organism of any species is male, it must possess a Y chromosome.
The Y chromosome of any species is always smaller than the X chromosome.
The X and Y chromosomes are similar across all species, given the evolutionary relationship between these chromosomes.
all of these are false****

18

All organisms have either an X or Y chromosome, as these chromosomes are solely responsible for determining the sex of an individual. Mendel's failure to identify X and Y chromosomes in his pea plants invalidated a portion of the data he collected.

false

19

For rare X-linked traits, most of the affected individuals are males.

For rare X-linked traits, most of the affected individuals are males.

20

In a male fruit fly, the white-eye gene is carried on the Y chromosome.

false

21

A wild-type fruit fly:

exhibits the most common phenotype in the population.

22

In Figure 17.5a, none of the F2 females has white eyes. Why?

The allele for red eyes is dominant over white eyes, and these F2 females are either homozygous dominant (red-eye allele) or are heterozygous.

23

Which one of the following statements does not accurately describe the sex chromosomes?

The relative size and gene content of the X and Y chromosomes is very similar across species.

24

The frequency of recombination is expressed as the ratio of recombinants to the total number of progeny.

true

25

Imagine that a researcher is looking at the movement of sperm in a vial. He notices that although all the sperm tend to move upward, there is a group that consistently moves faster and reaches the top of the vial first. This may be the result of differences in which sex chromosome―either the YXor Y―the sperm contain. As X chromosomes are larger than Y chromosomes, Y-chromosome–bearing sperm may move faster.

true

26

The ratio of recombinants to total number of progeny can be simplified to a percentage, and 1% recombination is equal to 1 __________________, which represents the distance between two linked genes.

map unit

27

Two genes, A and B, are found on the same chromosome. One homologous chromosome carries alleles A and B, whereas the other homologous chromosome carries alleles a and b. If genes A and B are so closely linked that the recombination frequency is 0%, only AB and ab gametes will be produced during meiosis.

true

28

Genetic variations in DNA sequences in human populations, such as single nucleotide polymorphisms (SNPs), have been used to map "disease genes" by determining whether the SNP is linked to the mutant gene.

true

29

An X chromosome carrying the allele for white eyes is transferred from a male to a female of the next generation and in the next generation is transmitted back to the male again. This is called:

crisscross inheritance.

30

Which one of the following statements does not accurately describe segregation of the sex chromosomes?

In humans, the sex at each birth is not a random process because there are often large families with either all girls or all boys.