Which description best fits a cross where the parents are from different inbred strains?

Which description best fits a cross where the parents are from different inbred strains?

• A. Outcross
• B. Inbreed
• C. Hybrid
• D. Congenic

Answer: (C)

When two distinct inbred strains are crossed, the offspring are an F1 hybrid. Inbred strains are kept genetically uniform within each strain, so crossing them brings together two completely different genomes. The result is a organism that is heterozygous at many loci and carries traits from both parental lines, which is exactly what a hybrid describes. This differs from an inbred mating, which stays within one strain and increases homozygosity, and from a congenic situation, where a small genetic region from one strain is introduced into the background of another through backcrossing. Outcross is a broader term for mating unrelated individuals, but the specific scenario of two distinct inbred strains is most accurately called a hybrid.

When two distinct inbred strains are crossed, the offspring are an F1 hybrid. Inbred strains are kept genetically uniform within each strain, so crossing them brings together two completely different genomes. The result is a organism that is heterozygous at many loci and carries traits from both parental lines, which is exactly what a hybrid describes. This differs from an inbred mating, which stays within one strain and increases homozygosity, and from a congenic situation, where a small genetic region from one strain is introduced into the background of another through backcrossing. Outcross is a broader term for mating unrelated individuals, but the specific scenario of two distinct inbred strains is most accurately called a hybrid.