QUESTION 1
Which of these statements is correct?
a. Syntenic genes are located on the same chromosome.
b. Linked genes are always syntenic.
c. You cannot always predict the relative genetic distance from their physical distance on a chromosome.
d. All of the above.
1 points
QUESTION 2
What is the relative genetic distance between two linked genes if the recombination frequency is 0.32?
a. 32 cM
b. 3.2 cM
c. 0.32 cM
d. Not enough information is provided to answer this question.
1 points
QUESTION 3
What statement best explains the distortion in Mendelian ratios observed by Bateson & Punnett in 1905? (Reminder: they found an overrepresentation of F2 offspring showing both dominant or recessive phenotypes, and an underrepresentation of offspring displaying one dominant and one recessive phenotype)
a. Human error: they should have been more careful about their experimental setup.
b. Gene linkage: Genes for flower color and pollen shape are physically close on the same chromosome, leading to a breakdown in the independent assortment of the alleles for these traits.
c. Chromosome crossover: Homologous recombination of two chromatids during meiosis caused the alleles to shuffle, resulting in a breakdown of the independent assortment of the alleles for those genes.
d. Random variation: No two situations are alike. In finite populations, you are going to get some variation across a mean.
1 points
QUESTION 4
Researchers investigating the genome of the red imported fire ant, Solenopsis invicta, discovered that two genes are located about 100 base pairs apart on the same chromosome. They also found that the chromosome in question is undergoing no recombination at all. What is the relative genetic distance between those genes?
a. 100 cM
b. 0 cM
c. 10 cM
d. 50 cM
1 points
QUESTION 5
The two genes F and G, code for body size and aggressiveness, respectively. The F allele codes for a larger body size, and is dominant over f allele that codes for a smaller body size. The G allele codes for aggressive behavior, and is dominant over gallele that codes for docile behavior. You perform a Mendelian dihybrid cross (NOT a test cross) on these traits. If there is no recombination between these genes (recombination frequency = 0.00), what ratio should you see phenotypes in in the offspring? (note that the parent generation was made up of large aggressive ants and small docile ants.)
a. 9 large aggressive : 3 large docile : 3 small aggressive : 1 small docile
b. 1 large aggressive : 1 large docile : 1 small aggressive : 1 small docile
c. 12 large aggressive : 4 small docile (i.e. 3 large aggressive : 1 small docile)
d. None of the above.
1 points
QUESTION 6
When determining the relative genetic distance between two genes, why is dihybrid back-cross preferable over traditional dihybrid cross?
a. 9:3:3:1 phenotypic ratio is easier to work with than 1:1:1:1 ratio.
b. Genotypes of the offspring can be determined based on their phenotype.
c. Unlike the traditional dihybrid cross, dihybrid back-cross produces all possible combinations of genotypes.
d. All of the above.
QUESTION 1
Which of these statements is correct?
| a. | Syntenic genes are located on the same chromosome. | |
| b. | Linked genes are always syntenic. | |
| c. | You cannot always predict the relative genetic distance from their physical distance on a chromosome. | |
| d. | All of the above. |
1 points
QUESTION 2
What is the relative genetic distance between two linked genes if the recombination frequency is 0.32?
| a. | 32 cM | |
| b. | 3.2 cM | |
| c. | 0.32 cM | |
| d. | Not enough information is provided to answer this question. |
1 points
QUESTION 3
What statement best explains the distortion in Mendelian ratios observed by Bateson & Punnett in 1905? (Reminder: they found an overrepresentation of F2 offspring showing both dominant or recessive phenotypes, and an underrepresentation of offspring displaying one dominant and one recessive phenotype)
| a. | Human error: they should have been more careful about their experimental setup. | |
| b. | Gene linkage: Genes for flower color and pollen shape are physically close on the same chromosome, leading to a breakdown in the independent assortment of the alleles for these traits. | |
| c. | Chromosome crossover: Homologous recombination of two chromatids during meiosis caused the alleles to shuffle, resulting in a breakdown of the independent assortment of the alleles for those genes. | |
| d. | Random variation: No two situations are alike. In finite populations, you are going to get some variation across a mean. |
1 points
QUESTION 4
Researchers investigating the genome of the red imported fire ant, Solenopsis invicta, discovered that two genes are located about 100 base pairs apart on the same chromosome. They also found that the chromosome in question is undergoing no recombination at all. What is the relative genetic distance between those genes?
| a. | 100 cM | |
| b. | 0 cM | |
| c. | 10 cM | |
| d. | 50 cM |
1 points
QUESTION 5
The two genes F and G, code for body size and aggressiveness, respectively. The F allele codes for a larger body size, and is dominant over f allele that codes for a smaller body size. The G allele codes for aggressive behavior, and is dominant over gallele that codes for docile behavior. You perform a Mendelian dihybrid cross (NOT a test cross) on these traits. If there is no recombination between these genes (recombination frequency = 0.00), what ratio should you see phenotypes in in the offspring? (note that the parent generation was made up of large aggressive ants and small docile ants.)
| a. | 9 large aggressive : 3 large docile : 3 small aggressive : 1 small docile | |
| b. | 1 large aggressive : 1 large docile : 1 small aggressive : 1 small docile | |
| c. | 12 large aggressive : 4 small docile (i.e. 3 large aggressive : 1 small docile) | |
| d. | None of the above. |
1 points
QUESTION 6
When determining the relative genetic distance between two genes, why is dihybrid back-cross preferable over traditional dihybrid cross?
| a. | 9:3:3:1 phenotypic ratio is easier to work with than 1:1:1:1 ratio. | |
| b. | Genotypes of the offspring can be determined based on their phenotype. | |
| c. | Unlike the traditional dihybrid cross, dihybrid back-cross produces all possible combinations of genotypes. | |
| d. | All of the above. |
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Related textbook solutions
Related questions
Which of these statements is incorrect?
Syntenic genes are located on the same chromosome. |
Independent assortment results in recombinant chromosomes. |
You can reliably predict the relative genetic distance fromgenesâ physical distance on a chromosome. |
Linked genes are always syntenic. |
What is the relative genetic distance between two linked genesif the recombination frequency is 0.49?
0.49 cM |
4.9 cM |
49 cM |
490 cM |
What statement best explains the distortion in Mendelian ratiosobserved by Bateson & Punnett in 1905? (Reminder: they found anoverrepresentation of F2 offspring showing both dominant orrecessive phenotypes, and an underrepresentation of offspringdisplaying one dominant and one recessive phenotype)
| Human error: they should have been more careful about theirexperimental setup. |
| Gene linkage: Genes for flower color and pollen shape arephysically close on the same chromosome, leading to a breakdown inthe independent assortment of the alleles for these traits. |
| Chromosome crossover: Homologous recombination of twochromatids during meiosis caused the alleles to shuffle, resultingin a breakdown of the independent assortment of the alleles forthose genes. |
Random variation: No two situations are alike. In finitepopulations, you are going to get some variation across a mean. |
When determining the relative genetic distance between twogenes, why is dihybrid back-cross preferable over traditionaldihybrid cross?
| 9:3:3:1 phenotypic ratio is easier to work with than 1:1:1:1ratio. |
| Genotypes of the offspring can be determined based on theirphenotype. |
If the genes are independently assorted, the dihybrid back-crosswould result in only 2 genotypes in the F1 generation. |
B and C |
Why do we map genes?
| To understand how genes interact with each other |
| Comparative genomics analysis |
| To determine the genotype of an organism |
| All of the above |
Please show detailed work. Thanks in advance.
16. Syntenic genes can assort independently when
A) they are very close together on a chromosome.
B) they are located on different chromosomes.
C) crossing over occurs rarely between the genes.
D) they are far apart on a chromosome and crossing over occurs frequently between the genes.
E) they are far apart on a chromosome and crossing over occurs very rarely between the genes.
17. The alleles of linked genes tend to
A) segregate together more often than expected by random assortment
B) assort independently.
C) be mutated more often than unlinked genes.
D) experience a higher rate of crossing over.
E) assort independently and show a higher rate of crossing over.
18. If you know that the frequency of recombination between genes X and Y is 34% and between X and Z is 25%, can you predict the order of the three genes?
A) Yes; the order is X-Z-Y.
B) Yes; the order is X-Y-Z.
C) Yes; the order is Z-X-Y.
D) No; based on this data alone, the order could be Z-Y-X or X-Y-Z.
E) No; based on this data alone, the order could be X-Z-Y or Z-X-Y.
Question 19 - 20. You have performed the following dihybrid cross in Drosophila using the black body color (b) and vestigial wing (vg) mutations. The b+ (grey body) and vg+ (normal wing) are dominant wild type alleles. These genes are autosomal.
Female â b+ vg+/b vg à male â b vg/b vg
Progeny:
Phenotype # of Progeny
Grey body normal wing 965
Black body vestigial wing 944
Grey body vestigial wing 208
Black body normal wing 195
19. Assuming linkage between black and vestigial, the estimated recombination frequency would be:
0.17
0.09
0.82
1.00
0.50
20. What key test could you use to determine whether the observed offspring frequencies deviate from those expected by chance alone?
A) Pascal's triangle
B) The product rule
C) The Chi-square (Ï2) test
D) The law of random assortment
E) The sum rule
21. In a genome wide association study (GWAS) designed to map the gene(s) that control height you divide subjects into a group of 1000 who are all more than seven feet tall and a control group of 1000 people of average height. You find the following associations between two genetic markers and the height trait:
| Tall group | Control group | ||
| Marker 1 | Allele A | 20% | 50% |
| Allele T | 80% | 50% | |
| Marker 2 | Allele G | 15% | 15% |
| Allele C | 85% | 85% |
What is your best guess for which marker is more closely linked to a gene that influences height?
A) Marker 1
B) Marker 2
22. Two pure breeding parents produce red and white flowers. They are crossed and the F1 produces pink flowers. When the F1 are selfed to produce the F2, nine distinct classes of pigmentation are present among F2 individuals. What is your best guess of the minimum number of genes that underlie flower pigmentation in this species?
A. 2
B. 3
C. 4
D. 5
E. 6
23. In a quantitative genetic experiment you identify two genes that confer bands of color on the back of a fly. At each gene, a dominant allele causes one band of color. If flies that are heterozygous at both loci are crossed, what ratio of offspring do you expect in each phenotype (i.e., number of color bands) class? (answer options are given from lowest to highest band number)
A) 1:1:1:1:1
B) 1:2:2:2:1
C) 1:4:6:4:1
D) 4:4:4:4:4
