Which of the following best describes the inheritance pattern of traits in Morgan's study of fruit flies?

The correct answer is sex linkage, which is a key concept illustrated by Thomas Hunt Morgan's experiments with fruit flies, specifically Drosophila melanogaster. In his research, Morgan discovered that certain traits, such as eye color, were inherited differently depending on the sex of the organism. He found that these traits were associated with genes located on the X chromosome, which led to the conclusion that the inheritance pattern was influenced by the sex of the individual.

This discovery played a foundational role in our understanding of genetics by revealing that some traits do not follow the simple dominance and recessiveness patterns observed in Mendelian inheritance. Instead, sex-linked traits are inherited in a manner that differs between males and females, due to the presence of different sex chromosomes. For instance, in fruit flies, males have one X and one Y chromosome, while females have two X chromosomes. This difference leads to unique inheritance patterns for traits that are located on the X chromosome.

In contrast, the other options describe different genetic phenomena that do not apply to Morgan's specific findings about fruit flies. Dominance and recessiveness refer to a concept where one allele masks the effect of another, which is not the primary focus of Morgan's work. Codominance describes a scenario where both