Assistant Laboratory Animal Technician (ALAT) Practice Exam

Which type of animal has had a gene "turned off" by scientists?

1. Transgenic animal

2. Knockout animal

3. Genetically-modified organism

4. Hybrid animal

The correct answer is: Knockout animal

The correct choice is comprised of animals that have had a specific gene inactivated or "knocked out." This process involves targeted changes to the organism's genome, leading to the loss of function of that particular gene. This technique is crucial in research as it helps scientists study the role of specific genes in development, physiology, and disease. By observing the differences in phenotype or function when a gene is turned off, researchers can gain insights into gene function and contribute to the understanding of genetic diseases. Transgenic animals, while they may incorporate foreign genes, are not necessarily characterized by having genes turned off. Genetically-modified organisms is a broader term that can encompass both transgenic and knockout animals along with other modifications, which doesn't specifically denote the inactivation of a gene. Hybrid animals refer to the offspring resulting from the mating of different species or breeds and do not imply any genetic modification but rather natural genetic combination. Thus, the term for animals that have had a specific gene "turned off" is knockout animals, emphasizing the targeted manipulation of the genome for experimental purposes.