SYSTEMATIC BIOLOGY

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SUPERGROUP UNIKONTA

In 1993 Baldauf and Palmer demonstrated the phylogenetic relationship between the animals and fungi by using sequences of 25 proteins.  This followed a suggestion by Cavalier-Smith (1987) that animals and fungi evolved from a choanoflagellate-like line.  Since then, other work (Cavalier-Smith and Chao, 1995; and Cavalier-Smith, 1996) strengthened the link and called the group, the Opisthokonts in reference to the posteriorly-directed flagellum in motile cells.  Other work (e.g. van de Peer et al., 2000; and Keeling, 2004) has confirmed a sister group relationship between the Amoebozoae and the Opisthokonts.  Tentatively, this group is called the Unikonta, in reference to the occurrence of a single flagellum in their motile cells.

For further information, go to the Evolution of the Eukaryotic Supertree.

A table of four distinguishing features (flagella, covering, mitochondria, and meiosis) among 12 groups of unikonts.

GROUP FLAGELLA COVERING MITOCHONDRIA MEIOSIS
PELOBIONTS ANTERIOR OR INTERNAL NAKED HYDROGENOSOMES ABSENT
RHIZOPODA ANTERIOR (1) NAKED/ ORGANIC COVERING TESTS & SPORES TUBULAR CRISTAE ABSENT
MYXOMYCOTA ANTERIOR (2) NAKED/CHITIN TUBULAR CRISTAE PRESENT
DICTYOSTELA ABSENT NAKED/ ORGANIC COVERING SPORES TUBULAR CRISTAE ABSENT
APUSOZOA ANTERIOR + POSTERIOR ORGANIC THECA FLAT & TUBULAR CRISTAE ABSENT
CHYTRIDS POSTERIOR (1) CHITIN  FLAT CRISTAE PRESENT
MICROSPORIDIA ABSENT SPORE WALL OF 3 LAYERS ABSENT SUSPECTED
AMASTIGOTE FUNGI ABSENT CHITIN/ CHITOSAN/GLUCAN FLAT CRISTAE PRESENT/ ABSENT IN FUNGI IMPERFECTI
CHOANOFLAGELLATES POSTERIOR (1) NAKED WITH SILICACEOUS SPICULES FLAT CRISTAE NOT KNOWN
NUCLEARIIDA        
ICHTHYOSPOREA        
METAZOA POSTERIOR (1) VARIABLE; GENERALLY NAKED/ ORGANIC OF CHITIN CUTIN MOSTLY WITH FLAT CRISTAE PRESENT

REFERENCES.

This page is maintained by Jack R. Holt: 03/06/2007