One successful form of gene therapy has involved delivery of an allele for the enzyme adenosine deaminase (ADA) to bone marrow cells of a child with SCID, and delivery of these engineered cells back to the bone marrow of the affected child. What is one major reason for the success of this procedure as opposed to many other efforts at gene therapy?

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#Question id: 13080

#Unit 13. Methods in Biology

In RAPDs amplification will take place only of those regions of the genome that have the 

TLS Online TPP Program

#Question id: 13081

#Unit 13. Methods in Biology

Correct statements about RAPD’s

A. RAPD polymorphism is detected by using oligonucleotides usually more than 10 bases long of random sequences as primers in a reaction.

B. In a strain which has in genomic DNA sequences complementary to the primer oligonucleotide, PCR products will be detected in the gel,

C. Typical RAPD markers show limited variation between parents, especially in naturally inbreeding species.

D. RAPDs are more sensitive than RFLPs to experimental conditions making them more difficult to be consistent and reproducible.

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#Question id: 13082

#Unit 13. Methods in Biology

Statement: AFLP shares some features of both RFLP and RAPD analyses.

Explanations: I. It uses restriction enzyme-digested genomic DNA as template for PCR amplification using primers that contain the restriction enzyme recognition sites plus a number of, usually 2-3, arbitrary nucleotides.

II. AFLPs are faster, less labour intensive and provide more information than RFLPs, and they are highly reproducible, which is a great advantage over RAPDs.

TLS Online TPP Program

#Question id: 13083

#Unit 13. Methods in Biology

The genomic DNA of an organism is digested with two restriction enzymes; one of the, PstI (CTGCA/G), while the other., MseI (T/TAA). This would generate the following 3 types of DNA fragments: 

(1) both ends cleaved by PstI (Pst-Pst), 

(2) both ends cleaved by MseI (Mse-Mse), and 

(3) one end generated by each of the two enzymes (Pst-Mse). 

the most frequent fragments in decreasing order,

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#Question id: 13084

#Unit 13. Methods in Biology

Statement: In a modified version of AFLP, the selection of fragments using biotin-streptavidin binding is avoided.

Explanations: I. The fragments are ligated to the appropriate adapters and used for PCR amplification using two AFLP primers, each primer having a single selection nucleotide; this is called preamplification step.

II. The PCR products from this preamplificated step are diluted and used as template for second PCR amplification.

TLS Online TPP Program

#Question id: 13085

#Unit 13. Methods in Biology

The most common microsatellite sequence encountered in human genome is the sequence