The apterous gene in Drosophila encodes a protein required for wing patterning and growth. It is also known to function in nerve development, fertility, and viability. When human and mouse genes whose protein products closely resemble apterous were used to generate transgenic Drosophila [Rincon-Limas et al. (1999). Proc. Nat. Acad. Sci. (USA) 96:2165–2170], the apterous mutant phenotype was rescued. In addition, the whole-body expression patterns in the transgenic Drosophila were similar to normal apterous.
What is meant by the term rescued in this context?

Verified step by step guidance

1. Understand that in genetics, the term 'rescued' refers to the restoration of a normal phenotype in an organism that has a mutation causing a defective or altered trait.
2. In this context, the apterous gene mutation in Drosophila causes defects in wing patterning, nerve development, fertility, and viability, leading to an abnormal phenotype.
3. When human and mouse genes similar to apterous are introduced into the mutant Drosophila, these genes produce proteins that can perform the function of the missing or defective apterous protein.
4. The term 'rescued' means that the introduction of these foreign genes compensates for the mutation, restoring the normal wing patterning and other functions, effectively reversing the mutant phenotype.
5. Therefore, 'rescued' indicates that the mutant phenotype caused by the defective apterous gene is corrected or alleviated by the expression of the homologous genes from other species.

Key Concepts

Gene Rescue

Gene rescue refers to the restoration of a normal phenotype in an organism that has a mutant gene, by introducing a functional copy of that gene or a similar gene. In this context, it means that the mutant Drosophila lacking functional apterous protein regained normal wing patterning and other functions when human or mouse homologs were expressed.

Homologous Genes and Functional Conservation

Homologous genes are genes in different species that evolved from a common ancestor and often retain similar functions. The ability of human and mouse genes to rescue the Drosophila apterous mutant indicates functional conservation, meaning these genes produce proteins that can substitute for each other across species.

Transgenic Organisms

Transgenic organisms are genetically modified to carry genes from other species. In this case, Drosophila were engineered to express human and mouse genes, allowing researchers to study gene function and cross-species gene compatibility by observing phenotypic changes.