The karyotype of four Trichinella species

Mutafova, T.; Dimitrova, Yana D.; Komandarev, S.

doi:10.1007/bf00929519

Cited by 16 publications

(8 citation statements)

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“…The T. muris genome comprises two pairs of autosomes and one pair of X and Y sex chromosomes (2n = 6) 7 , while the karyotype of T. trichiura has so far not been reported. In Trichinella species of the same phylogenetic clade, the XO-sex determination system is used with 2n = 6 for female (XX) and 2n = 5 for male (X0) worms 8 . To explore the architecture of the genome, assembly scaffolds of T. muris were joined into super-scaffolds by optical mapping (assembly version 4.0, Table 1).…”

Section: Resultsmentioning

confidence: 99%

Whipworm genome and dual-species transcriptome analyses provide molecular insights into an intimate host-parasite interaction

et al. 2014

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Whipworms are common soil-transmitted helminths that cause debilitating chronic infections in man. These nematodes are only distantly related to Caenorhabditis elegans and have evolved to occupy an unusual niche, tunneling through epithelial cells of the large intestine. Here we present the genome sequences of the human-infective Trichuris trichiura and the murine laboratory model T. muris. Based on whole transcriptome analyses we identify many genes that are expressed in a gender- or life stage-specific manner and characterise the transcriptional landscape of a morphological region with unique biological adaptations, namely bacillary band and stichosome, found only in whipworms and related parasites. Using RNAseq data from whipworm-infected mice we describe the regulated Th1-like immune response of the chronically infected cecum in unprecedented detail. In silico screening identifies numerous potential new drug targets against trichuriasis. Together, these genomes and associated functional data elucidate key aspects of the molecular host-parasite interactions that define chronic whipworm infection.

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Section: Resultsmentioning

confidence: 99%

Whipworm genome and dual-species transcriptome analyses provide molecular insights into an intimate host-parasite interaction

et al. 2014

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“…melanogaster in this respect. It is also the only nematode we have studied which has monocentric chromosomes [16]. In the report describing the genome sequence of this species no mention is made of the eventual presence of either telomeric repeats (Mo10) or centromeric satellites [17].…”

Section: Resultsmentioning

confidence: 99%

A Satellite Explosion in the Genome of Holocentric Nematodes

Subirana

Messeguer

2013

PLoS ONE

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Centromere sequences in the genome are associated with the formation of kinetochores, where spindle microtubules grow in mitosis. Centromere sequences usually have long tandem repeats (satellites). In holocentric nematodes it is not clear how kinetochores are formed during mitosis; they are distributed throughout the chromosomes. For this reason it appeared of interest to study the satellites in nematodes in order to determine if they offer any clue on how kinetochores are assembled in these species. We have studied the satellites in the genome of six nematode species. We found that the presence of satellites depends on whether the nematode chromosomes are holocentric or monocentric. It turns out that holocentric nematodes are unique because they have a large number of satellites scattered throughout their genome. Their number, length and composition are different in each species: they apparently have very little evolutionary conservation. In contrast, no scattered satellites are found in the monocentric nematode Trichinella spiralis. It appears that the absence/presence of scattered satellites in the genome distinguishes monocentric from holocentric nematodes. We conclude that the presence of satellites is related to the holocentric nature of the chromosomes of most nematodes. Satellites may stabilize a higher order structure of chromatin and facilitate the formation of kinetochores. We also present a new program, SATFIND, which is suited to find satellite sequences.

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“…The best known group of holocentric species can be found in the Secernentea class of the nematodes, which includes C. elegans [16,17]. Other nematodes are usually described as holocentric because of their phylogenetic relationship to C. elegans, but real karyotypic evidences are scarce or controversial [30][31][32]. Nematode development is typically characterized by fixed lineages, therefore, it has been suggested that holocentrism could avoid the disastrous consequences of unrepaired chromosome breakage events [33].…”

Section: Holocentric Chromosomes In Nematodesmentioning

confidence: 99%

Holocentric chromosomes

Mandrioli

Manicardi

2020

PLoS Genet

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Holocentric chromosomes possess multiple kinetochores along their length rather than the single centromere typical of other chromosomes [1]. They have been described for the first time in cytogenetic experiments dating from 1935 and, since this first observation, the term holocentric chromosome has referred to chromosomes that: i. lack the primary constriction corresponding to centromere observed in monocentric chromosomes [2]; ii. possess multiple kinetochores dispersed along the chromosomal axis so that microtubules bind to chromosomes along their entire length and move broadside to the pole from the metaphase plate [3]. These chromosomes are also termed holokinetic, because, during cell division, chromatids move apart in parallel and do not form the classical V-shaped figures typical of monocentric chromosomes [4-6]. Holocentric chromosomes evolved several times during both animal and plant evolution and are currently reported in about eight hundred diverse species, including plants, insects, arachnids and nematodes [7,8]. As a consequence of their diffuse kinetochores, holocentric chromosomes may stabilize chromosomal fragments favouring karyotype rearrangements [9,10]. However, holocentric chromosome may also present limitations to crossing over causing a restriction of the number of chiasma in bivalents [11] and may cause a restructuring of meiotic divisions resulting in an inverted meiosis [12]. Evolution and structure of holocentric chromosomes Evolution of holocentric chromosomes Holocentric chromosomes were described for the first time in 1935 to identify chromosomes with a diffuse kinetochore (or with a diffuse kinetochore activity) making these chromosomes able to bind to microtubules along their entire length. In the last decades, several studies assessed that the same behaviour during mitosis can be observed not only for holocentric/ holokinetic chromosomes, but also for polykinetic chromosomes that contain numerous (but discrete) microtubule-binding sites, but the term "holocentric/holokinetic" is still used for both [1,5,7]. Before molecular methods became available, the presence of holocentric chromosomes was evaluated mostly using cytology and, considering that many species are difficult to study cytologically, it can be surmised that the true presence of holocentrism may be underestimated. In addition, there are several taxa, whose chromosomes are still uncharacterized, but their

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The karyotype of four Trichinella species

Cited by 16 publications

References 1 publication

Whipworm genome and dual-species transcriptome analyses provide molecular insights into an intimate host-parasite interaction

Whipworm genome and dual-species transcriptome analyses provide molecular insights into an intimate host-parasite interaction

A Satellite Explosion in the Genome of Holocentric Nematodes

Holocentric chromosomes

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