You have crossed two Drosophila melanogaster individuals that have long wings and red eyes—the wild-type phenotype. In the progeny, curved wings and lozenge eyes mutant phenotypes appear as follows According to these data, is the curved-wing allele autosomal recessive, autosomal dominant, sex-linked recessive, or sex-linked dominant?

Verified step by step guidance

1. Examine the phenotypic ratios in the progeny. The data shows that both males and females exhibit curved wings and lozenge eyes, indicating that these traits are not sex-limited.
2. Consider the inheritance pattern of the curved wings trait. If the trait were autosomal dominant, all offspring would exhibit curved wings if one parent had curved wings. However, not all offspring have curved wings, suggesting it is not autosomal dominant.
3. Evaluate the possibility of the curved wings trait being autosomal recessive. In this case, both parents would need to carry the recessive allele for some offspring to exhibit curved wings. The presence of curved wings in both males and females supports this hypothesis.
4. Assess the sex-linked inheritance possibility. If the trait were sex-linked recessive, it would predominantly appear in males if the mother were a carrier. However, curved wings appear in both sexes, making sex-linked recessive inheritance unlikely.
5. Conclude that the curved wings trait is most likely autosomal recessive, as it appears in both males and females without a bias towards one sex, and not all offspring exhibit the trait, indicating recessive inheritance.

Key Concepts

Drosophila melanogaster Genetics

Drosophila melanogaster, commonly known as the fruit fly, is a model organism in genetics. Its simple genetic structure and short life cycle make it ideal for studying inheritance patterns. The phenotypes of Drosophila, such as wing shape and eye color, are often used to illustrate Mendelian genetics, where traits are inherited according to specific ratios based on dominant and recessive alleles.

Autosomal vs. Sex-linked Traits

Traits can be classified as autosomal or sex-linked based on their location on chromosomes. Autosomal traits are found on non-sex chromosomes and are inherited equally by both sexes, while sex-linked traits are located on sex chromosomes and often exhibit different inheritance patterns in males and females. Understanding this distinction is crucial for interpreting genetic crosses and predicting offspring phenotypes.

Phenotypic Ratios and Inheritance Patterns

Phenotypic ratios represent the relative frequencies of different traits in the offspring of a genetic cross. Analyzing these ratios helps determine the inheritance pattern of traits, such as whether they are dominant or recessive, and whether they are autosomal or sex-linked. In this case, the observed ratios of curved wings and lozenge eyes in the progeny can provide insights into the genetic basis of these phenotypes.