What serves as an example of subfunctionalization of a gene duplicate?

Subfunctionalization of a gene duplicate occurs when each copy of a duplicated gene evolves to specialize in a different aspect of the original gene's function. In the case of hemoglobin genes, the duplication allows for the evolution of different versions that can be expressed in various contexts or developmental stages. For instance, different hemoglobin genes can be adapted for the specific oxygen transport needs of embryos compared to adults. This diversification allows for greater flexibility and specialization in function, highlighting how gene duplication can lead to enhanced evolutionary potential by maintaining and fine-tuning distinct roles for each duplicate.

Other options discuss different evolutionary processes. The second option pertains more to loss of function rather than the specialization of functions in duplicates. The third option relates to gene fusion, which involves combining two genes rather than splitting a function between duplicates. Finally, the fourth option indicates modifications of existing proteins and does not directly involve gene duplication or subfunctionalization. Thus, the example of hemoglobin gene duplication aptly illustrates how subfunctionalization can lead to the establishment of distinct functional roles within evolutionary biology.