Energy allocation in two species of Eutardigrada

Guidetti, Roberto; Colavita, Chiara; Altiero, Tiziana; Bertolani, Roberto; Rebecchi, Lorena

doi:10.4081/jlimnol.2007.s1.111

Cited by 9 publications

(7 citation statements)

References 21 publications

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“…Although our laboratory cultures of H. dujardini are, to our knowledge, completely parthenogenic, consisting exclusively of females, males of the species and the genus Hypsibius have been reported (26) and meiosis occurs in H. dujardini (27), suggesting that a high degree of HGT may be a common feature of animals that survive desiccation rather than animals that lack sex and meiosis.…”

Section: Resultsmentioning

confidence: 99%

Evidence for extensive horizontal gene transfer from the draft genome of a tardigrade

Boothby

Tenlen

Smith

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

166

189

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Horizontal gene transfer (HGT), or the transfer of genes between species, has been recognized recently as more pervasive than previously suspected. Here, we report evidence for an unprecedented degree of HGT into an animal genome, based on a draft genome of a tardigrade, Hypsibius dujardini. Tardigrades are microscopic eight-legged animals that are famous for their ability to survive extreme conditions. Genome sequencing, direct confirmation of physical linkage, and phylogenetic analysis revealed that a large fraction of the H. dujardini genome is derived from diverse bacteria as well as plants, fungi, and Archaea. We estimate that approximately one-sixth of tardigrade genes entered by HGT, nearly double the fraction found in the most extreme cases of HGT into animals known to date. Foreign genes have supplemented, expanded, and even replaced some metazoan gene families within the tardigrade genome. Our results demonstrate that an unexpectedly large fraction of an animal genome can be derived from foreign sources. We speculate that animals that can survive extremes may be particularly prone to acquiring foreign genes.

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Section: Resultsmentioning

confidence: 99%

Evidence for extensive horizontal gene transfer from the draft genome of a tardigrade

Boothby

Tenlen

Smith

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

166

189

View full text Add to dashboard Cite

show abstract

“…In eutardigrade species, the morphological changes during the life cycle had previously been linked only to morphometric (e.g. Guidetti et al ., ; Bartels, Nelson & Exline, ) or to sexual characters (Rebecchi & Nelson, ).…”

Section: Discussionmentioning

confidence: 99%

Morphological and molecular analyses onRichtersius(Eutardigrada) diversity reveal its new systematic position and lead to the establishment of a new genus and a new family within Macrobiotoidea

et al. 2016

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Important contributions have been made to the systematics of Eutardigrada in recent years, but these have also revealed that several taxa are polyphyletic and that cryptic species are present. To shed light on the taxonomy and systematic position of the genus Richtersius (Eutardigrada, Macrobiotoidea), six populations attributed to Richtersius coronifer were collected and analysed from morphological (light and scanning electron microscopy) and molecular (mitochondrial cytochrome oxidase subunit 1, 18S, 28S) points of view. In particular, a new morphometric index (claw common tract: length of the common tract of the claw/total claw length 9 100) and a new morphological character (stalk system) were introduced. Our integrative study was able to unveil the 'cryptic' species diversity within Richtersius, showing that the genus contains more than one evolutionary lineage. A morphological peculiarity in the animals of all lineages is the dimorphism in the morphology of the cuticle. Cuticular pores are present in the newborns and are lost with the first moult; this morphological change represents a novelty in the life cycle of eutardigrades. The phylogenetic analyses carried out on Richtersius populations and other Macrobiotoidea show that Richtersius is closely related to Macrobiotus islandicus, whereas Adorybiotus granulatus is more related to Richtersius and M. islandicus than to other members of the genus Macrobiotus (type genus of Macrobiotidae); therefore, the genus Macrobiotus and the family Macrobiotidae are not monophyletic. Based on these results, the new genus Diaforobiotus (for M. islandicus) and the new family Richtersiidae (composed of Richtersius, Diaforobiotus gen. nov., and Adorybiotus) are established.

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“…For P. richtersi, diploid bisexual biotypes (2n=12) and triploid parthenogenetic biotypes (3n=18) have been noted (Guidetti et al 2007;Hohberg and Greven 2005;Ramazzotti and Maucci 1983). In the present study, however, all animals came from parthenogenetic strains, with the exception of the outgroups M. sapiens and P. tonollii (unpublished data).…”

Section: Discussionmentioning

confidence: 95%

Using compensatory base change analysis of internal transcribed spacer 2 secondary structures to identify three new species in Paramacrobiotus (Tardigrada)

et al. 2010

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Species within the tardigrade genus Paramacrobiotus could be distinguished via an analysis of internal transcribed spacer 2 (ITS2) secondary structures. Sequences of P. richtersi and four populations previously treated under provisional names (Paramacrobiotus 'richtersi group' 1 to 4) from different continents were determined and annotated, and their secondary structures were predicted. A tree based on a combined sequence-structure alignment was reconstructed by Neighbor-Joining. The topology obtained is consistent with a tree based on a distance matrix of compensatory base changes (CBCs) between all ITS2 sequence-structure pairs in the global multiple alignment. The CBC analysis, together with 18S rDNA sequences, physiological, biochemical and biophysical data identified three species new to science that are morphologically indistinguishable from P. richtersi. These are formally described under the names Paramacrobiotus fairbanksi sp. nov., P. kenianus sp. nov., and P. palaui sp. nov.

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Energy allocation in two species of Eutardigrada

Abstract: To

Cited by 9 publications

References 21 publications

Evidence for extensive horizontal gene transfer from the draft genome of a tardigrade

Evidence for extensive horizontal gene transfer from the draft genome of a tardigrade

Morphological and molecular analyses onRichtersius(Eutardigrada) diversity reveal its new systematic position and lead to the establishment of a new genus and a new family within Macrobiotoidea

Using compensatory base change analysis of internal transcribed spacer 2 secondary structures to identify three new species in Paramacrobiotus (Tardigrada)

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