Question

If a probe for Southern blot was dissolved in a hybridization buffer that contains 50% formamide, is the stringency of hybridization higher or lower than if there were no formamide.

a. True
b. False

Answer 1

The stringency of hybridization is higher in the presence of 50% formamide in the hybridization buffer used for a Southern blot, as formamide acts as a denaturing agent to ensure that only DNA sequences highly complementary to the probe will effectively hybridize.

Step-by-step explanation:

The presence of formamide in the hybridization buffer actually increases the stringency of hybridization in a Southern blot. Formamide is a denaturing agent that lowers the melting temperature of the nucleic acid duplexes, which means that only DNA sequences that are highly complementary to the probe will hybridize effectively under these conditions. Thus, when a probe for Southern blotting was dissolved in a hybridization buffer that contains 50% formamide, the stringency of hybridization is higher compared to a buffer without formamide.