Bikont

Lore & Background

Bikonts are characterized by the fusion of two genes—thymidylate synthase and dihydrofolate reductase—into a single unit that encodes a bifunctional protein. This trait is shared across the group and contrasts with unikonts, where these genes are separately translated. The group encompasses a diverse array of organisms, including plants (Archaeplastida), Excavata, Rhizaria, and Chromalveolata, with some research also placing Apusozoa within Bikonta.

Reader's Guide

The concept of Bikonta is significant in eukaryotic taxonomy as it proposes a fundamental split between unikonts (ancestral to animals, fungi, and Amoebozoa) and bikonts (ancestral to plants and several other major lineages). This division helps organize the tree of life, though relationships within bikonts remain unresolved. Some studies suggest alternative groupings, such as Cabozoa (Excavata and Rhizaria) and Corticata (Archaeplastida and Chromalveolata), while others propose a clade uniting Rhizaria and Chromalveolata. The 2015 proposal of the term Diphoda as a substitute reflects ongoing debate. The group's defining genetic fusion and flagellar structure provide key markers for evolutionary studies, though the monophyly of subgroups like Archaeplastida and Hacrobia is still disputed.

Did You Know?

• Bikonts have two flagella, as do their presumed ancestor.
• The genes for thymidylate synthase and dihydrofolate reductase are fused into a single protein in bikonts.
• Cavalier-Smith suggested that Apusozoa, typically considered incertae sedis, are bikonts.
• An alternative name for bikonts is Diphoda, proposed in 2015.