Question

Pick the statement about mutation that is false.

		Gain-of-function mutations are usually recessive.
		Tandem duplications can be generated by strand slippage during replication.
		Depruination of a nucleotide can happen spontaneously.
		The Ames test measures reversion frequencies.
		Intercalating agents cause frameshift mutations.

Answer 1

The first statement is false. Gain-of-function mutations are usually dominant. This mutation results in a new function of the gene leading to a diffrent phenotype. Loss-of-function mutations are generally recessive. This is because the other allele compensates for the mutated allele.

Rest four statements are correct. In replication, strand slippage can occur leading to the repeated duplications, called tandem duplications. Dupurination refers to removal of a purine (A,G). This may occur spontaneously and changes cytosine to uracil. The ames test measures mutagenecity of a chemical compound. It can also trace reverse mutations in bacteria. Intercalating agents like EtBr get stacked between base pairs. It inserts or deletes a base, causing frameshift mutations.