BIO 325 Study Guide - Midterm Guide: Synteny, Ploidy, Centromere

Flies with a dominant mutation in a particular gene have an additional set of wings. Through mapping techniques, you identify a candidate gene, gene X, on an autosomal chromosome that you think results in extra wings when mutated. When you sequence gene X in the mutant fly with extra wings, you notice a missense mutation in the middle of the coding region of gene X. What is the best way to verify that the mutation in gene X is responsible for the dominant phenotype?

a. Starting with a wild-type fly, knockout gene X to generate a null allele and see if flies that are heterozygous or homozygous for the null allele have extra wings.

b. Starting with the mutant fly that is heterozygous for the dominant allele, insert a wild type copy of gene X (complete with its own promoter) elsewhere in the genome of the fly and see if it rescues the mutant and results in normal/wild-type wings.

c. Starting with a mutant fly that is heterozygous for the dominant allele, replace the dominant mutant allele with a wild type version of the gene via homologous recombination and see whether flies with the replacement have normal/wild type wings.

d. Starting with a homozygous wild-type fly, replace one copy of wild-type gene X with a version carrying the dominant mutation via homologous recombination, and see whether flies with the replacement have extra wings.

e. either C or D

You have a strain of flies that are homozygous for a deletion of 2 neighboring genes, A and B (genotype aabb). Wild type flies have transparent wings but these aabb flies have rainbow-colored wings. Which of the following experiments would provide you with more information about which of these genes (if either) is responsible for the rainbow-colored wings?

a. Starting with a wild-type fly, create a transgenic fly that is homozygous for deletion in both genes A and B and see if you get the rainbow-colored wings.

b. Delete gene A alone and gene B alone in 2 independent wild-type flies and see whether flies homozygous for either deletion have rainbow-colored wings.

c. Starting with a mutant fly with rainbow-colored wings, introduce both wildtype genes A and B into a new place in the genome of the fly and see if normal wing color is restored.

d. non of the above

Expression vectors inprokaryotes do not make functional eukaryotic gene products inbacteria very well because

Answer Not sure which one ?!

I create a knockout mouseusing the agouti/black fur system \. When I cross the agoutioffspring of the originally engineered mouse, I find a ratio of 2agouti mice to 1 black furred mouse. What is the bestexplanation?

Answer not sure which one?!

A restriction enzyme cuts DNAand leaves the following end

xxCTGCA
xxG

Which of the following could be the sequence of the correspondingend of the other end of the cut DNA?

Answer

I PCR out a mutated gene in apatient with Lisenbee chorea (the inability to dance in acoordinated fashion) and I compare it to another patient with thatsame disease phenotype. One subject had a mutation on chromosome 4,and the other subject couldn't rock it because of a mutation onchromosome 5. This is an exampe of

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A mosaic is an organismwith

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Question

Genotype causesphenotype.

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Question

A true genetic chimera can becreated by

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Question

The ABO blood group can bestbe explained by the concept of _______.

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If a loss of functionmutation creates a dominant phenotype, it may be becauseof

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Please select the best matchfor each.

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A gene mutates, and theprotein produced has a novel way of interacting with the cell, andcreates a new phenotype because of this new functionality. This iscalled

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Question 62

Mutations in the somaticchromosomes may be inherited by the next generation.

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· True

· False

A degenerate PCR primer withmany variant sequences must be used to make multiple copies of agene

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Question

Please select the best matchfor each term.

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Question

A couple goes on MauryPovitch, and the results are in: you are not the father. But noother man impregnated the female (granted, unlikely for a MauryPovitch guest, but work with me here) and he must be the father.DNA analysis claims otherwise, though the child definitely wasmom's (poor thing). What may be going on here?

Answer

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 ♀ b+ vg+/b vg × male ♂ 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 (χ²) 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:

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