Living Environment Regents Practice Test

What genetic change led to the development of the antifreeze gene in icefish?

1. Gene duplication

2. Mutation

3. Gene transfer

4. Chromosomal crossover

The correct answer is: Mutation

The genetic change that led to the development of the antifreeze gene in icefish is best described by mutation. Specifically, a mutation occurred that allowed for the expression of antifreeze proteins, which help icefish survive in their frigid ocean habitats by preventing the formation of ice crystals in their blood and tissues. This adaptation is crucial for their survival in extremely low temperatures. Mutations can include a wide range of changes, such as single nucleotide substitutions, deletions, or insertions, which can result in the creation of new proteins or the alteration of existing ones. In the case of icefish, mutations provided them with a unique survival feature that was advantageous in their icy environments. While gene duplication, gene transfer, and chromosomal crossover are all important mechanisms in the evolution of species, they did not specifically account for the development of the antifreeze protein in icefish. Gene duplication usually involves the copying of existing genes, creating redundancy that can lead to new gene functions over time. Gene transfer refers to the movement of genetic material between organisms, typically found in bacteria. Chromosomal crossover involves the exchange of genetic material during meiosis, which increases genetic diversity but doesn’t directly relate to the development of antifreeze capabilities in these fish. Therefore, the most accurate