ASCP Exam Study Guide with Questions and Answers

ASCP Exam Study Guide with Questions and Answers what is a solution hybridization method for the detection of nucleic acid: protein interactions? a. RNase protection assay b. gel mobility shift assay c. strand displacement amplification assay d. hybrid capture assay ANSWER b. a gel mobility shift assay involves mixing a labeled oligonucleotide with a protein extract to see if specific protein:nucleic acid interaction occurs. the oligonucleotide will exhibit an apparent increases in molecular size on a gel due to its association with a protein should such an interaction occur. Which probe is most often used to detect trisomy 21 by interphase FISH: a. locus-specific probe b. alpha satellite DNA probe c. chromosome paint probe d. spectral karyotyping probe ANSWER b. alpha satellite probes are centromere-specific and can be used to identify specific chromosomes. a chromosome 21-specific alpha satellite probe would give 3 distinct dots in interphase cells. chromosome paint probes have greater utility in metaphase spreads to detect translocations or other alterations in chromosome structure. a unique sequence probe specific for chromosome 21 could also be theoretically used, but would give a weaker signal compared to the alpha satellite probe due to the highly repetitive nature of the alpha satellite sequence. how many volumes of ethanol are added to 1 volume of a DNA:salt solution to cause the DNA to precipitate? a. 1 b. 1.5