Exam 16: Forward Genetics and Recombinant DNA Technology

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?

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

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?

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

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

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

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?

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

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

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

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?

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

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

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?

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?

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

-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?

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?

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.

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?