title: Comparative genomics of the marine bacterial genus  Glaciecola reveals the high degree of genomic  diversity and genomic characteristic for  cold adaptation.
abstract: To what extent the genomes of different species belonging to one genus can be diverse and the relationship between genomic differentiation and environmental factor remain unclear for oceanic bacteria. With many new bacterial genera and species being isolated from marine environments, this question warrants attention. In this study, we sequenced all the type strains of the published species of Glaciecola, a recently defined cold-adapted genus with species from diverse marine locations, to study the genomic diversity and cold-adaptation strategy in this genus.The genome size diverged widely from 3.08 to 5.96 Mb, which can be explained by massive gene gain and loss events. Horizontal gene transfer and new gene emergence contributed substantially to the genome size expansion. The genus Glaciecola had an open pan-genome. Comparative genomic research indicated that species of the genus Glaciecola had high diversity in genome size, gene content and genetic relatedness. This may be prevalent in marine bacterial genera considering the dynamic and complex environments of the ocean. Species of Glaciecola had some common genomic features related to cold adaptation, which enable them to thrive and play a role in biogeochemical cycle in the cold marine environments.
authors.forename: Qi-Long
authors.initials: QL
authors.lastname: Qin
authors.forename: Bin-Bin
authors.initials: BB
authors.lastname: Xie
authors.forename: Yong
authors.initials: Y
authors.lastname: Yu
authors.forename: Yan-Li
authors.initials: YL
authors.lastname: Shu
authors.forename: Jin-Cheng
authors.initials: JC
authors.lastname: Rong
authors.forename: Yan-Jiao
authors.initials: YJ
authors.lastname: Zhang
authors.forename: Dian-Li
authors.initials: DL
authors.lastname: Zhao
authors.forename: Xiu-Lan
authors.initials: XL
authors.lastname: Chen
authors.forename: Xi-Ying
authors.initials: XY
authors.lastname: Zhang
authors.forename: Bo
authors.initials: B
authors.lastname: Chen
authors.forename: Bai-Cheng
authors.initials: BC
authors.lastname: Zhou
authors.forename: Yu-Zhong
authors.initials: YZ
authors.lastname: Zhang
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics; D034241:Alteromonadaceae / Q000235:genetics*; D001483:Base Sequence; D064112:Clustered Regularly Interspaced Short Palindromic Repeats; D022761:Gene Transfer, Horizontal; D014644:Genetic Variation; D016680:Genome, Bacterial; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA