In transgenic lineage nomenclature, which description corresponds to the first generation offspring of the founder?

• A. Founder
• B. The first generation offspring of the founder of a line
• C. The second generation offspring of the founder of a line
• D. The brother-sister mating of founders of a line

Answer: (B)

The key idea is that the founder represents the initial transgenic animal (generation zero), and the first generation refers to its direct offspring. The phrase “The first generation offspring of the founder of a line” precisely describes the animals produced when the founder is bred, capturing that they are the immediate progeny of the founder and not the founder itself. This distinguishes them from the second generation (offspring of the first generation) and from breeding two founders together. In short, the offspring produced directly from the founder are the first generation, making that description the correct choice.