Genetic Linkage & Mapping – Ch6 Test Bank | 7th Ed

View Product website:

https://selldocx.com/docx/genetic-linkage-mapping-ch6-test-bank-7th-ed-1295

Student name:__________

1) Which of the following defines the principle of linkage? Check all that apply.

A) Two or more genes that are physically connected on a chromosome.
B) Genes that are transmitted to the next generation as a group.
C) The process by which genetic information is exchanged between homologous chromosomes.

2) Assume that genes C and D are located on the same chromosome. On one chromosome, alleles C and D are found, while the homolog contains alleles c and d. Which of the following would be evidence of a recombination event? Check all that apply.

A) Alleles C and D together on one chromosome.
B) Alleles c and d together on one chromosome.
C) Alleles C and d together on one chromosome.
D) Alleles c and D together on one chromosome.

3) Select each true statement regarding sexual reproduction in ascomycetes. Check all that apply.

A) In fungi likeNeurospora crassa, the diploid structures are called spores.
B) The end result of meiosis in fungi is a tetrad of spores.
C) A fungal reproductive structure that contains all of the products of a single meiotic division is called the ascus.
D) In fungal gene mapping, the abbreviation NPD stands for new parental ditype.
E) An ascus that contains two parental spores and two nonparental spores is called a tetratype.

4) The first observational evidence that genes may be inherited together rather than by simple Mendelian inheritance was provided by __________.

A) Mendel
B) Morgan and Bridges
C) Bateson and Punnett
D) Boveri and Sutton
E) None of these choices are correct.

5) Experimental evidence that crossing over occurs between the X chromosomes of female Drosophila was provided by __________.

A) Morgan
B) Punnett
C) Darwin
D) Bateson

6) Which of the following statistical tests is used to determine if two genes are linked or assorting independently?

A) Sum rule
B) Binomial expansion
C) Product rule
D) Chi-square test

7) In a chi-square test to determine if two genes are linked or assorting independently, what is the default (null) hypothesis that is tested?

A) The genes are linked to one another.
B) The genes are assorting independently.
C) The genes are located on the sex chromosomes.
D) No crossing over occurs.
E) The distance between the genes is very small.

8) The visual proof that chromosomes exchange pieces of information during crossing over was provided by __________.

A) Bateson and Punnett
B) Morgan and Bridges
C) Creighton and McClintock
D) Watson and Crick

9) Twin spotting provides evidence of what genetic event?

A) Meiotic recombination
B) Mitotic recombination
C) Linkage
D) Mutation
E) Biological evolution

10) An organism that contains patches of tissue that vary for a specific characteristic such as a pigment, can be an example of which of the following?

A) Linkage
B) Meiotic recombination
C) Mitotic recombination
D) Translocations

11) Crossing over is more likely to occur between genes that are __________ on a chromosome.

A) close together
B) far apart

12) A testcross is always performed between the individual that is heterozygous for the genes to be mapped and an individual who is ____________.

A) heterozygous for the genes
B) homozygous dominant for the genes
C) homozygous recessive for the genes
D) lacking the genes

13) While mapping two genes in Drosophila, you observe 30 recombinants among 200 total offspring. What is the distance between these genes?

A) 30 map units
B) 6.67 map units
C) 200 map units
D) 15 map units

14) A map distance of 23.6 between two genes indicates which of the following?

A) The genes are 23.6 millimeters apart.
B) There are 23.6 other genes between the two genes of interest.
C) 23.6% of the offspring exhibit recombination between the two genes.
D) 23.6% of the offspring do not survive.

15) In a mapping experiment with three linked genes, which phenotype should occur most often in the F2 offspring?

A) Parental phenotypes.
B) Phenotypes of individuals with single crossover events.
C) Phenotypes of individuals with double crossover events.
D) All of the phenotypes should occur equally in the F2 generation.

16) The middle gene of a three gene mapping experiment can be determined by examining the genotypes of which of the following?

A) Offspring that resemble the parents.
B) Offspring that exhibit a single crossover event.
C) Offspring that exhibit double crossover events.

17) In a given mapping experiment, you expect that incidence of double crossovers is 3.5%, but you only observe 2.5%. This can be explained by ________________.

A) interference
B) linkage
C) coincidence
D) segregation

18) You have calculated the interference value for a given mapping experiment to be 30%. What does this mean?

A) 30% more double crossovers occurred than expected.
B) 30% fewer double crossovers occurred than expected.
C) 70% more double crossovers occurred than expected.
D) 70% fewer double crossovers occurred than expected.

19) Which of the following is not one of the principles of linkage that Morgan obtained from his experiments?

A) Genes that are onthe same chromosome may be inherited together.
B) Crossing over exchanges pieces of chromosomes and creates new allelecombinations.
C) The likelihood ofcrossing over occurring between two genes is dependent on the distance of thegenes from one another.
D) Genes that are onthe same chromosome are always transmitted together as a unit.

20) In humans, there are __________ autosomal linkage groups, plus a linkage group for each sex chromosome.

A) 23
B) 46
C) 22
D) 92

21) Another name for a chromosome is a __________, since it contains genes that are often inherited together.

A) linkage group
B) crossing overgroup
C) geneticrecombinant
D) bivalent

22) Two genes that are located on the same chromosome are said to be __________.

A) physically linked
B) recombinant
C) parental-like
D) nonparental-like

23) Creighton and McClintock worked with _______ and their model system to show that homologous chromosomes physically exchange genetic information during crossing over.

A) fruit flies
B) peas
C) corn
D) tobacco

24) In certain algae and in most ascomycete fungi, the nuclei in the cells present in the majority of their life cycle are in the __________ condition.

A) diploid
B) haploid
C) triploid
D) tetraploid

25) Which of the following procedures may be used to map genes in a fungi with an unordered tetrad ascus?

A) Testcross
B) Monohybrid cross
C) Dihybrid cross
D) Chi-square analysis
E) Analysis of interference

26) The diploid garden pea plant has 14 chromosomes. The haploid fungus Neurospora crassa has 7 chromosomes. Neither organism has separate male and female individuals. Which of the following correctly identifies the number of linkage groups in each organism?

A) Garden pea has 14 linkage groups, and Neurospora has 7.
B) Garden pea has 7 linkage groups, and Neurospora has 7.
C) Garden pea has 8 linkage groups, and Neurospora has 8.
D) Gardent pea has 15 linkage groups, and Neurospora has 8.

27) The number of linkage groups in an organism with a single type of sex chromosome equals __________, where n equals the haploid number of autosomes.

A) 1n
B) 2n +1
C) 1n + 1
D) 2n + 2

28) The number of linkage groups in a species that does not have sex chromosomes equals __________, wheren equals the haploid number of autosomes.

A) 1n
B) 1n + 1
C) 2n
D) 2n + 2

29) The locus B on the X chromosome of a malaria-carrying mosquito shows a 49% recombination rate with respect to the locus M. Since a recombination rate of 50% is essentially indistinguishable from independent assortment, you might be tempted to look for a locus that falls between B and M. Before you decide to do all that work, you run a chi square test to determine the P value of your experiment. Which of the following P values would be most likely to tell you that you should accept the conclusion that locus B and locus M are, indeed, 49mu apart and that another locus is not necessary?

A) P = 0.45
B) P = 0.01
C) P = 0.005
D) P = 0.0007

30) In a mapping cross, you determine that the recombination frequency between theQ and P is 12% and betweenloci Q and L is 15%. If locus Q is in between loci P and L, then the recombination frequency between P and L should be approximately __________.

A) 3%
B) 27%
C) 50%
D) 75%

31) You notice that in most biology and genetics textbooks, the authors show that Gregor Mendel used flower color as one of his pairs of traits. The purple flower phenotype is dominant to the white flower phenotype. However, if you go back to Mendel's experiments, you see that he actually studied seed coat color. The purple seed coat phenotype was dominant to the white seed coat phenotype. Mendel did note that plants with purple seed coats had purple flowers and plants with white seed coats had white flowers.
Is the gene for seed coat color pleiotropic because it also affects flower color, or are the seed coat color gene and the flower color gene very closely linked? To find out the answer to this question, you assume that the genes for flower color and seed coat color are different genes, and your null hypothesis is that they assort independently. You designate the flower color gene wf and the seed coat color gene sw. Plants that are WF__, SW___ have purple flowers and purple seed coats. Plants that are wf wf, ws ws have white flowers and white seed coats.
You do the testcross WF wf, SW sw X wf wf, sw sw and collect 15,206 offspring. What result would tell you that the wf and sw loci are probably the same, pleiotropic locus?

A) One of the offspring had white flowers and purple seed coats.
B) About half of the offspring had purple flowers and purple seed coats, and all the rest had white flowers and white seed coats.
C) All of the offspring had purple flowers and purple seed coats.
D) None of the offspring had white flowers and white seed coats.

32) If you want to determine how the alleles of different loci interact in their various combinations, it is best to have a system where you do not have to worry about dominance and recessiveness. Which of the following would represent a system where you do not have to worry about dominance and recessiveness?

A) Homo sapiens
B) Garden peas
C) Drosophila melanogaster
D) Chlamydomonas reinhardtii

33) Mitotic recombination occurs between homologous chromosomes. In which of the following would you not expect to encounter mitotic recombination?

A) The fungus, Aspergillus nidulans
B) Tobacco plants
C) Homo sapiens
D) Drosophila melanogaster

34) Pintail is a dominant trait in mice in which individuals present with shorter tails than their wildtype counterparts. Mice with the clasper phenotype displaywhole body tremor followed by clasping of the paws while suspended by the tail. A cross between a female mouse showing only the pintail phenotype and a male mouse showing only the clasper phenotype yields two offspring: a female mouse showing only the pintail phenotype and a wildtype male. Each trait is controlled by one gene, and the two genes are located 10 mu apart from one another on chromosome 4. What is the probability that an offspring produced by a mating of the two F1 progeny will show both traits?

A) 0%
B) 2.5%
C) 5%
D) 10%
E) 25%

35) In Drosophila, the genes reduced (rd) bristles and withered (whd) wing are both found on chromosome 2, with their respective positions indicated on the chromosome map depicted below. A female with reduced bristles and normal wings was mated to a male with normal bristles and withered wings. All of the F1 offspring were phenotypically wild-type. What proportion of the progeny resulting from a testcross of an F1 female is expected to be phenotypically wild-type?

A) 0%
B) 5%
C) 10%
D) 45%
E) 100%

36) In Drosophila, the genes reduced (rd) bristles and withered (whd) wing are both found on chromosome 2. You have isolated a new recessive mutation in Drosophila that results in corrugated (corr) veins. χ2-analysis has revealed that corr is linked to the genes rd and whd on Chr. 2. You perform a three-point cross to determine the relative order of the three genes. Two pure-breeding mutant lines were crossed to produce an F1 female that is normal in appearance for all three traits. The phenotypes of 1000 progeny resulting from a testcross of an F1 female are summarized below.
380withered, reduced
385 corregated
44 withered, corregated
41 reduced
7 withered
8 corregated, reduced
65 wildtype
70 withered, corregated, reduced
Which gene is in the middle?

A) corr
B) rd
C) whd

37) In Drosophila, the genes reduced (rd) bristles and withered (whd) wing are both found on chromosome 2. You have isolated a new recessive mutation in Drosophila that results in corrugated (corr) veins. χ2-analysis has revealed that corr is linked to the genes rd and whd on Chr. 2. You perform a three-point cross to determine the relative order of the three genes. Two pure-breeding mutant lines were crossed to produce an F1 female that is normal in appearance for all three traits. The phenotypes of 1000 progeny resulting from a testcross of an F1 female are summarized below.
380 withered, reduced
385 corregated
44 withered, corregated
41 reduced
7 withered
8 corregated, reduced
65 wildtype
70 withered, corregated, reduced
What is the distance between corr and whd?

A) 10 mu
B) 15 mu
C) 20 mu
D) 25 mu
E) 30 mu

38) In Drosophila, the linked genes black (b) body, reduced (rd) bristles, and withered (whd) wing are arranged on chromosome 2 as follows:

b-2.5 mu--rd-----10 mu-----whd

You testcross a female heterozygous at all three loci with a homozygous recessive male and obtain 2000 testcross progeny. When the progeny are analyzed, you find 2 double-crossover offspring. What is the interference value shown by this cross?

A) 0.025
B) 0.1
C) 0.2
D) 0.4
E) 0.6

39) The process of recombination may rarely occur during mitosis.

⊚ true
⊚ false

40) A genetic linkage map indicates that precise distance between two genes of interest.

⊚ true
⊚ false

41) Genetic linkage is the rearrangement of alleles that is achieved by the process of crossing over.

⊚ true
⊚ false

42) Map distance is equal to the number of recombinant offspring divided by the total number of nonrecombinant offspring.

⊚ true
⊚ false

43) Following crossing-over, chromosomes with genetic combinations that resemble the parents' chromosomes are called nonrecombinant.

⊚ true
⊚ false

44) A map unit or centimorgan is equal to a 10% recombination frequency.

⊚ true
⊚ false

45) Map distances above 50 are considered unreliable due to the occurrence of double-crossovers between the genes.

⊚ true
⊚ false

46) The locus is the physical place of a gene on a chromosome.

⊚ true
⊚ false

47) The percentage of recombination associated with independent assortment should approximate 50%.

⊚ true
⊚ false

48) The genotype hsp+ HSP- is something that you could easily expect to find in the fungus Neurospora crassa.

⊚ true
⊚ false

49) If two loci are extremely linked, then no recombination is expected.

⊚ true
⊚ false

50) Stern was able to demonstrate crossing over by using the X chromosomes in corn.

⊚ true
⊚ false

51) Gene mapping is useful because a genetic counselors can use a genetic map to determine if an individual will express a particular allele of a gene.

⊚ true
⊚ false