Question 1

If mutagenizing a number of Drosophila results in several observable phenotypes but also in several lethal mutations,does this mean that recessive lethal mutations cannot be studied further?

Accepted Answer

A)  No;the lethal allele can be recovered from heterozygous siblings.
B)  No;the lethal alleles can be sequenced from the other embryos.
C)  Yes;lethal alleles can be studied only if they are recessive.
D)  Yes;lethal alleles can be studied only if they are conditional.
E)  Yes;unless the lethal allele can be supplemented with a missing gene product. A

Question 2

For a contiguous sequence to be most useful in molecular mapping of a particular mutation,what should the contiguous sequence include?

Accepted Answer

two markers on either side of the mutation

Question 3

Whether libraries are cDNA or genomic,whether amplification is based on PCR or cloning,and whether screening is done with northern or Southern blotting or probes,all are based on which of the following?

Accepted Answer

A)  complementarity
B)  complementation
C)  reverse transcription
D)  reverse translation
E)  gene expression A

Question 4

-Which of the following would make a human disorder-causing allele or gene easiest to locate?

Accepted Answer

A)  a genomic library for the chromosome on which the gene is located
B)  a cDNA library for the chromosome on which the gene is located
C)  a group of 10 known candidate genes
D)  a transposon known to segregate with the gene
E)  a single patient with a chromosomal translocation associated with the gene

Question 5

Each restriction enzyme comes from a particular bacterial strain.Why does a restriction enzyme not destroy the bacterial strain's own DNA?

Accepted Answer

The answer of Each restriction enzyme comes from a particular...

Question 6

Should we allow (or urge)testing of minor age children or teens for adult-onset disorders for which there is no treatment or cure?

Accepted Answer

The answer of Should we allow (or urge)testing of minor...

Question 7

Genes for regulatory elements,such as creb,were found to be important in animal learning.Which of the following would increase the probability that such an element is studied throughout the animal kingdom?

Accepted Answer

A)  its unique sequence in Drosophila
B)  the finding that creb is highly conserved
C)  the number of repeats of the creb gene
D)  the interaction of creb with cAMP
E)  the finding that creb activates odor perception

Question 8

Conditional alleles result in phenotypic differences in permissive as opposed to restrictive conditions.What do these conditions have in common?

Accepted Answer

The answer of Conditional alleles result in phenotypic differences in...

Question 9

What technique of genomic library construction allows the genome to be cut by a given restriction enzyme at some but not all recognition sequences?

Accepted Answer

The answer of What technique of genomic library construction allows...

Question 10

A genetic strategy that starts with knowing the DNA sequence and works toward identifying an associated phenotype is known as ________.

Accepted Answer

The answer of A genetic strategy that starts with knowing...

Question 11

In producing a recombinant plasmid to be used to clone a given donor insert,it is possible to cut both the donor and plasmid with the same restriction enzyme,resulting in complementary sticky ends.Assuming plenty of plasmid DNA is available,why is further selection necessary before the introduction of the plasmid into a cellular system?

Accepted Answer

A)  Contamination will have introduced other donor inserts.
B)  Some donor inserts will be single stranded and deteriorate.
C)  Some donor inserts will be sensitive to particular antibiotics.
D)  Some donor pieces will remain uninserted.
E)  Some donor strands will be inserted with an incorrect orientation.

Question 12

Describe two or more ethical issues arising from sequencing the genomes of individuals.

Accepted Answer

The answer of Describe two or more ethical issues arising...

Question 13

What genetically determines the difference in frequency of restriction fragments from two different enzymes used on the same genome?

Accepted Answer

The answer of What genetically determines the difference in frequency...

Question 14

DNA markers that are found to segregate with a mutation of interest can be used to determine the mutation's distance from the markers by looking at what?

Accepted Answer

The answer of DNA markers that are found to segregate...

Question 15

A researcher wants to mutagenize an organism.He is not in need of a large number of mutants but is more concerned with being able to find and then to amplify the mutated sequence.Which of the following would therefore be more useful?

Accepted Answer

A)  ionizing radiation
B)  UV radiation
C)  transposon insertion
D)  a chemical mutagen
E)  search for spontaneous mutant

Question 16

Would it be possible and/or appropriate to design a genetic screen to look for a gene(s)involved in homosexuality?

Accepted Answer

The answer of Would it be possible and/or appropriate to...

Question 17

-In a disease associated with a nucleotide repeat,anticipation is often noticed in subsequent generations,usually associated with a more severe phenotype.Which of the following is a more likely cause of anticipation?

Accepted Answer

A)  There is more frequent unequal crossing over.
B)  Subtle phenotypic nuances are more often sought by a physician.
C)  Family members are exposed to the same mutagens.
D)  Highly repeated sequences are expressed more often.
E)  The sequences have greater stability in later generations.

Question 18

In mapping the HD gene associated with Huntington disease,eventually researchers narrowed down their hunt to four candidate genes within the mapped region.How did they identify one of these as the definitive HD gene?

Accepted Answer

The answer of In mapping the HD gene associated with...

Question 19

In the process of identifying mutations in animals,dominant mutations can be found after one generation of mating between the mutagenized male organism and wild-type female.To identify the non-sex-linked (autosomal)recessive mutants requires ________ generations.

Accepted Answer

The answer of In the process of identifying mutations in...

Question 20

You have a DNA sequence of 1600 bp.To characterize it,you decide to make a restriction map.Cutting with the first enzyme,you show by electrophoresis that the fragments produced are 400 and 1200 bp respectively.After using the second enzyme,you recover 700-bp and 900-bp fragments.After treatment with both enzymes,fragments were 300,400,and 900 bp.Which is the correct map?

Accepted Answer

A)  -900 ------/400--/3---
B)  -400/--900-----/300 ---
C)  -300-/--400--/--900----
D)  -400-/300-/---900-----
E)  -400-/-100/--300--/900

Exam 16: Forward Genetics and Recombinant DNA Technology