Early evolution of eukaryotes inferred by combined phylogeny of multiple genes

• Project/Area Number: 17370086
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Evolutionary biology
• Research Institution: University of Tsukuba
• Principal Investigator: HASHIMOTO Tetsuo University of Tsukuba, Grad. Sch. Life Environ. Sci., Professor (50208451)
• Co-Investigator(Kenkyū-buntansha): INOUYE Isao University of Tsukuba, Grad. Sch. Life Environ. Sci., Professor (70168433) ; NAKAYAMA Takeshi University of Tsukuba, Grad. Sch. Life Environ. Sci., Lect. (40302369) ; INAGAKI Yuji University of Tsukuba, Grad. Sch. Life Environ. Sci., Assoc. Prof. (50387958)
• Project Period (FY): 2005 – 2006
• Project Status: Completed (Fiscal Year 2006)
• Budget Amount: ¥14,200,000 (Direct Cost: ¥14,200,000); Fiscal Year 2006: ¥2,700,000 (Direct Cost: ¥2,700,000); Fiscal Year 2005: ¥11,500,000 (Direct Cost: ¥11,500,000)
• Keywords: eukaryotes / higher-order phylogeny / molecular phylogeny / maximun likelihood method / combined phylogeny / centrohelids / chromalyeolates hypothesis / fornicates

Research Abstract

In order to elucidate a higher-order phylogeny of eukaryotes infer a root of the eukaryotic tree, combined phylogeny of multiple genes were carried out. For this purpose, several genes encoding cytosolic ribosomal RNAs and conservative proteins were isolated and sequenced from various organisms belonging to stramenopiles, alveolates, centrohelids, cryptomonads, rhodophytes, and fornicates. Including original sequence data obtained, various kinds of data sets with different taxon samplings and with different selections of genes were generated and these were analyzed by combined maximum likelihood analyses of the multiple genes. Until recently major outcomes listed below have been obtained:
1. Optimal trees locating centrohelids at the outgroup position to bikont organisms and locating between the branches of amoebozoa and opisthokonts were independently obtained by different data sets, but these locations were not clearly supported with statistical confidence.
2. No clear support was obtained for the monophyly of chromalveolates including cryptophytes, haptophytes, stramenopiles, and alveolates.
3. Phylogenies of elongation factors 1 α and 2 demonstrated that Dysnectes brevis and a flagellate resemble to D. brevis (NY0173) were located between the branchings of trichomonads and diplomonads, supporting the previous results based on the SSUrRNA phylogeny.

Research Products

• [Journal Article] Centrohekida is still searching for phylogenetics home : molecular data analyses of seven Raphidiophrys contrastilis genes (2007)
  • Author(s): Sakaguchi, M., Inagaki Y., and Hashimoto, T.
  • Journal Title: Gene 405 Pages: 47-54
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Occurrence of multiple, independent gene fusion events for the fifth and sixth enzymes of pyrimidine biosynthesis in different eukaryotic groups (2007)
  • Author(s): Makiychi, T., Nara, T., Annoura, T., Hashimoto, T., and Aoki, T.
  • Journal Title: Gene 394 Pages: 78-86
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Ultrastructure and ribosomal RNA phylogeny of the free-living heterteoohic flagellate Dysnectis brevis n. gen., n. sp., a new member of the Fornicata (2007)
  • Author(s): Yubuki N, Inagaki Y, Nakayama T, Inouye I.
  • Journal Title: Journal of Eukaryotic Microbiolog 54 Pages: 191-200
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Uktrastructyral and phylogenetic studies on Blastocysitis isolates from cocroaches (2007)
  • Author(s): Yoshikawa, H., Wu, Z., Howe, J., Hashimoto, T., Geok-Choo, N., and Tan, K. S. W.
  • Journal Title: Journal of Eukaryotic Microbiology 54 Pages: 33-37
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Ultrastructural and phylogenetic studies on Blastocystis isolates from cockroaches (2007)
  • Author(s): Yoshikawa, H., Wu, Z., Howe, J., Hashimoto, T., Geok-Choo, N., Tan, K.S.W.
  • Journal Title: Journal of Eukaryotic Microbiology 54(1) Pages: 33-37
• [Journal Article] Ultrastructure and ribosomal RNA phylogeny of the free-living heterotrophic flagellate Dysnectis brevis n. gen., n. sp., a new member of the Fornicata (2007)
  • Author(s): Yubuki N, Inagaki Y, Nakayama T, Inouye I.
  • Journal Title: Journal of Eukaryotic Microbiology 54(2) Pages: 191-200
• [Journal Article] Occurrence of multiple, independent gene fusion events for the fifth and sixth enzymes of pyrimidine biosynthesis in different eukaryotic groups (2007)
  • Author(s): Makiuchi, T., Nara, T., Annoura, T., Hashimoto, T., Aoki, T.
  • Journal Title: Gene (Epub ahead of print)
• [Journal Article] 真核生物の系統進化研究の現状と課題 (2006)
  • Author(s): 橋本哲男, 有末伸子
  • Journal Title: 寄生虫分類形態談話会会報 23・24 Pages: 1-8
• [Journal Article] Phylogeny of the Centrehelida inferred from SSUrRNA, tubulins and actin genes (2005)
  • Author(s): Sakaguchi, M., Nakayama, T., Hashimoto, T., and Inouye, I.
  • Journal Title: Journal of Molecular Evolution 61 Pages: 765-775
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] A close relationship between Cercozoa, and Foraminifera supported by phylogenetic analyses based on combined amino acid sequences of three cytoakeletal proteins,(actin,α-tubulin, . and β-tubulin) (2005)
  • Author(s): Takishita, K., Inagaki, Y., Tsuchiya, M., Sakaguchi, M., and Maruyama, T.
  • Journal Title: Gene 362 Pages: 153-160
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Alternative oxidase (AOX) genes of African trypanosomes : pjylogeny and evolution of AOX and plastid terminal oxidase families (2005)
  • Author(s): Suzuki T, Hashimoto, T, Yabu, Y, Majiwa, PAO, Ohshima, S, Suzuki, M, Lu, S, Hato, M, Kido, Y, Sakamoto, K., Nakamura, K., Kita, K., Ohta, N
  • Journal Title: JOURNAL OF EUKARYOTIC MICROBIOLOGY 52(4) Pages: 374-381
• [Journal Article] Phylogeny of the centrohelida inferred from SSU rRNA, tubulins, and actin genes (2005)
  • Author(s): Sakaguchi M, Nakayama T, Hashimoto T, Inouye I
  • Journal Title: JOURNAL OF MOLECULAR EVOLUTION 61(6) Pages: 765-775
• [Journal Article] The katablepharids are a distant sister group of the Cryptophyta : A proposal for Katablepharidophyta divisio nova/Kathablepharida phylum novum based on SSU rDNA and beta-tubulin phylogeny (2005)
  • Author(s): Okamoto N, Inouye I
  • Journal Title: PROTIST 156(2) Pages: 163-179
• [Journal Article] A secondary symbiosis in progress? (2005)
  • Author(s): Okamoto N, Inouye I
  • Journal Title: SCIENCE 310(5746): Pages: 287-287
• [Journal Article] Ultrastructure and phylogenetic position of Chrysoculter rhomboideus gen. et sp nov(Prymnesiophyceae), a new flagellate haptophyte from Japanese coastal waters (2005)
  • Author(s): Nakayama T, Yoshida M, Noel MH, Kawachi M, Inouye I
  • Journal Title: PHYCOLOGIA 44(4) Pages: 369-383