title: The diversification of PHIS transposon superfamily in eukaryotes.
abstract: BACKGROUND
  PHIS transposon superfamily belongs to DNA transposons and includes PIF/Harbinger, ISL2EU, and Spy transposon groups. These three groups have similar DDE domain-containing transposases; however, their coding capacity, species distribution, and target site duplications (TSDs) are significantly different.
  
  
  RESULTS
  In this study, we systematically identified and analyzed PHIS transposons in 836 sequenced eukaryotic genomes using transposase homology search and structure approach. In total, 380 PHIS families were identified in 112 genomes and 168 of 380 families were firstly reported in this study. Besides previous identified PIF/Harbinger, ISL2EU, and Spy groups, three new types (called Pangu, NuwaI, and NuwaII) of PHIS superfamily were identified; each has its own distinctive characteristics, especially in TSDs. Pangu and NuwaII transposons are characterized by 5'-ANT-3' and 5'-C|TNA|G-3' TSDs, respectively. Both transposons are widely distributed in plants, fungi, and animals; the NuwaI transposons are characterized by 5'-CWG-3' TSDs and mainly distributed in animals.
  
  
  CONCLUSIONS
  Here, in total, 380 PHIS families were identified in eukaryotes. Among these 380 families, 168 were firstly reported in this study. Furthermore, three new types of PHIS superfamily were identified. Our results not only enrich the transposon diversity but also have extensive significance for improving genome sequence assembly and annotation of higher organisms.
authors.affiliation: School of Life Sciences, Chongqing University, Chongqing, 400044 China.
authors.forename: Min-Jin
authors.initials: MJ
authors.lastname: Han
authors.affiliation: School of Life Sciences, Chongqing University, Chongqing, 400044 China.
authors.forename: Chu-Lin
authors.initials: CL
authors.lastname: Xiong
authors.affiliation: School of Life Sciences, Chongqing University, Chongqing, 400044 China.
authors.forename: Hong-Bo
authors.initials: HB
authors.lastname: Zhang
authors.affiliation: School of Life Sciences, Chongqing University, Chongqing, 400044 China.
authors.forename: Meng-Qiang
authors.initials: MQ
authors.lastname: Zhang
authors.affiliation: College of Pharmacy and Life Science, Jiujiang University, Jiujiang, 332000 China.
authors.forename: Hua-Hao
authors.initials: HH
authors.lastname: Zhang
authors.affiliation: School of Life Sciences, Chongqing University, Chongqing, 400044 China.
authors.forename: Ze
authors.initials: Z
authors.lastname: Zhang
keywords: Diversification; Identification; PHIS; Transposable elements