Bikont

Taxobox
color = #taxobox colour|incertae sedis
name = Bikonts


image_caption = "Ceratium hirundinella"
domain = Eukaryota
subdivision_ranks = Supergroups
subdivision =
Apusozoa

Rhizaria

Excavata

Archaeplastida

Chromalveolata
A Bikont ("two flagella") is a eukaryotic cell with two flagella, as its name suggests. Another shared trait of bikonts is the fusion of two genes into a single unit: the genes for thymidylate synthase (TS) and dihydrofolate reductase (DHFR) encode a single
protein with two functions (Cavalier-Smith, 2006). The genes are separately translated in unikonts.

Some research suggests that a unikont (a eukaryotic cell with a single flagellum) was the ancestor of opisthokonts (Animals, Fungi and related forms) and Amoebozoa, and a bikont was the ancestor of Archaeplastida (Plants and relatives), Excavata, Rhizaria, and Chromalveolata. Cavalier-Smith has suggested that Apusozoa, which are typically considered "incertae sedis", are in fact bikonts.

Relationships within the bikonts are not yet clear. Cavalier-Smith has grouped the Excavata and Rhizaria into the Cabozoa and the Archaeplastida and Chromalveolata into the Corticata, but at least one other study has suggested that the Rhizaria and Chromalveolata form a clade. [cite journal | author = Burki F, Shalchian-Tabrizi K, Minge M, Skjæveland Å, Nikolaev SI, et al. | year = 2007 | title = Phylogenomics Reshuffles the Eukaryotic Supergroups | journal = PLoS ONE | volume = 2 | issue = 8: e790 | doi = 10.1371/journal.pone.0000790 | pages = e790]

References

* cite journal
author=Thomas Cavalier-Smith
title=Protist phylogeny and the high-level classification of Protozoa
journal=European Journal of Protistology
year=2006 | volume=39 | issue=4 |pages=338–348
doi=10.1078/0932-4739-00002

* cite journal
author=Alexandra Stechmann and Thomas Cavalier-Smith
title=The root of the eukaryote tree pinpointed
journal=Current Biology
year=2003 | volume=13 | issue=17