The Capsaspora genome reveals a complex unicellular prehistory of animals.
To reconstruct the evolutionary origin of multicellular animals from their unicellular ancestors, the genome sequences of diverse unicellular relatives are essential. However, only the genome of the choanoflagellate Monosiga brevicollis has been reported to date. Here we completely sequence the genome of the filasterean Capsaspora owczarzaki, the closest known unicellular relative of metazoans besides choanoflagellates. Analyses of this genome alter our understanding of the molecular complexity of metazoans' unicellular ancestors showing that they had a richer repertoire of proteins involved in cell adhesion and transcriptional regulation than previously inferred only with the choanoflagellate genome. Some of these proteins were secondarily lost in choanoflagellates. In contrast, most intercellular signalling systems controlling development evolved later concomitant with the emergence of the first metazoans. We propose that the acquisition of these metazoan-specific developmental systems and the co-option of pre-existing genes drove the evolutionary transition from unicellular protists to metazoans.
Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain.
Hiroshi
H
Suga
Zehua
Z
Chen
Alex
A
de Mendoza
Arnau
A
Sebé-Pedrós
Matthew W
MW
Brown
Eric
E
Kramer
Martin
M
Carr
Pierre
P
Kerner
Michel
M
Vervoort
Núria
N
Sánchez-Pons
Guifré
G
Torruella
Romain
R
Derelle
Gerard
G
Manning
B Franz
BF
Lang
Carsten
C
Russ
Brian J
BJ
Haas
Andrew J
AJ
Roger
Chad
C
Nusbaum
Iñaki
I
Ruiz-Trillo
D000818:Animals; D017209:Apoptosis / Q000235:genetics; D001483:Base Sequence; D005075:Biological Evolution; D002448:Cell Adhesion / Q000235:genetics; D056897:Choanoflagellata / Q000235:genetics* / Q000378:metabolism; D019143:Evolution, Molecular; D016678:Genome; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism; D050298:Mesomycetozoea / Q000235:genetics*; D008928:Mitochondria / Q000235:genetics; D010802:Phylogeny; D017434:Protein Structure, Tertiary / Q000235:genetics; D017422:Sequence Analysis, DNA; D015398:Signal Transduction / Q000235:genetics; D014158:Transcription, Genetic / Q000235:genetics
D036341:Intercellular Signaling Peptides and Proteins