- 作者：Gernot Gl枚ckner ; Norbert H眉lsmann ; Michael Schleicher ; Angelika聽A. Noegel ; Ludwig Eichinger ; Christoph Gallinger ; Jan Pawlowski ; Roberto Sierra ; Ursula Euteneuer ; Loic Pillet ; Ahmed Moustafa ; Matthias Platzer ; Marco Groth ; Karol Szafranski ; Manfred Schliwa
- 刊名：Current Biology
- 出版年：6 January, 2014
- 年：2014
- 卷：24
- 期：1
- 页码：11-18
- 全文大小：1083 K
Summary
Background
Rhizaria are a major branch of eukaryote evolution with an extensive microfossil record, but only scarce molecular data are available. The rhizarian species Reticulomyxa filosa, belonging to the Foraminifera, is free-living in freshwater environments. In culture, it thrives only as a plasmodium with thousands of haploid nuclei in one cell. The R.聽filosa genome is the first foraminiferal genome to be deciphered.Results
The genome is extremely repetitive, and the large amounts of identical sequences hint at frequent amplifications and homologous recombination events. Presumably, these mechanisms are employed to provide more gene copies for higher transcriptional activity and to build up a reservoir of gene diversification in certain gene families, such as the kinesin family. The gene repertoire indicates that it is able to switch to a single-celled, flagellated sexual state never observed in culture. Comparison to another rhizarian, the chlorarachniophyte alga Bigelowiella natans, reveals that proteins involved in signaling were likely drivers in establishing the Rhizaria lineage. Compared to some other protists, horizontal gene transfer is limited, but we found evidence of bacterial-to-eukaryote and eukaryote-to-eukaryote transfer events.
Conclusions
The R.聽filosa genome exhibits a unique architecture with extensive repeat homogenization and gene amplification, which highlights its potential for diverse life-cycle stages. The ability of R.聽filosa to rapidly transport matter from the pseudopodia to the cell body may be supported by the high diversification of actin and kinesin gene family members.