The Differentiation of Germ and Somatic Cell Lines in Nematodes

Tobler, Heinz

doi:10.1007/978-3-540-39838-7_1

Cited by 76 publications

(56 citation statements)

References 184 publications

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“…A similar phenomenon occurs in the selective elimination of so-called "limited" DNA from somatic cell lineages for several other species of copepods (Rasch and Wyngaard 1997;Grishanin and Akif'ev 2000), in ascarid nematodes (Tobler 1986), in Japanese hagfish (Kubota et al 1993), and in many species of ciliated protozoa (Coyne et al 1997). These systems provide an unusual opportunity to study genomic restructuring in the context of development and differentiation.…”

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confidence: 82%

Evidence for Endoreduplication: Germ Cell DNA Levels Prior to Chromatin Diminution in Mesocyclops edax

Rasch

Wyngaard

2001

J Histochem Cytochem.

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S U M M A R YWe studied the functional significance of marked differences in the DNA content of somatic cells and germ line nuclei by static Feulgen-DNA cytophotometry for several species of microcrustaceans that exhibit chromatin diminution during very early stages of embryogenesis. Mature females and males showed many gonadal nuclei with elevated amounts of DNA that persist until dispersal of this "extra" DNA throughout the cytoplasm as fragments and coalescing droplets of chromatin during anaphase of the diminution division.

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confidence: 82%

Evidence for Endoreduplication: Germ Cell DNA Levels Prior to Chromatin Diminution in Mesocyclops edax

Rasch

Wyngaard

2001

J Histochem Cytochem.

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“…The genetic phenomenon of a chromosomal germ line-soma differentiation with the occurrence of additional chromosomes, present only in germ line cells, was established in the dipteran families Cecidomyiidae, Chironomidae and Sciaridae, and also in some hagfish species (Vertebrata, Cyclostomata) (Kohno et al, 1986;Tobler, 1986;Kubota et al, 1993;Goday and Esteban, 2001;Redi et al, 2001). In the Orthocladiinae, a subfamily of the Chironomidae, the germ line-limited chromosomes (Ks; K being derived from "Keimbahn") and the soma chromosomes (Ss) pass through a complex chromosome cycle with interesting genetic features such as elimination mitoses and monopolar movements of chromosome complements (Bauer and Beermann, 1952;Bauer, 1970).…”

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confidence: 99%

Isolation of a new germ line-specific repetitive DNA family in <i>Acricotopus</i> by microdissection of polytenized germ line-limited chromosome sections from a permanent larval salivary gland preparation

Staiber

2002

Cytogenet Genome Res

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In Acricotopus lucidus (Diptera, Chironomidae) the germ line-limited chromosomes (Ks) have developed from the soma chromosomes (Ss) by endoreduplication, rearrangements and accumulation of germ line-specific repetitive sequences. For molecular analysis of specific small K sections, microdissection of metaphase Ks generally yields very limited amounts of DNA. In this study, K-specific DNA was microdissected from defined polytenized K sections of X-ray induced K-S-rearrangements of permanent salivary gland chromosome preparations and was then amplified by DOP-PCR. A new germ line-specific tandem repetitive DNA family was isolated by this way from a heterochromatic K segment, characterized and localized on the Ks by FISH. The repetitive elements are related to sequences of earlier described K-specific tandem repetitive DNA families in A. lucidus, but are located mainly in terminal heterochromatin bands of the two largest Ks and only to a limited degree in the paracentromeric K heterochromatin. This demonstrates that a collection of permanent preparations of K-S-rearrangements with polytenized heterochromatic and S-homologous K sections of A. lucidus can be used as a source for obtaining K sequences of defined K parts to investigate the molecular evolution of the Ks.

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“…This process has been described in several diverse groups of organisms, most notably nematodes, (reviewed by Tobler, 1986), protozoans (Cleftmann, 1980;Meyers & Lipps, 1980), insects (Brown & Nur, 1964;Rieffel & Crouse, 1966), and in the copepods (Beermann, 1977;Chinnappa, 1980). Diminution in the copepods differs in many respects from that occurring in the nematodes, protozoans, and insects, and has been extensively described by Beermann (1959Beermann ( , 1966Beermann ( , 1977Beermann ( , 1980Beermann ( , 1984, who studied several species in the genus Cyclops.…”

Section: Introductionmentioning

confidence: 99%

The effects of chromatin diminution on the pattern of C-banding in the chromosomes of Acanthocyclops vernalis Fischer (Copepoda: Crustacea)

Standiford

1989

Genetica

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Chromatin diminution is the loss of selected regions of pre-somatic cell chromosomes during early development, resulting in the removal of a large amount of the genomic DNA from the pre-somatic cells. In copepods, diminution is characterized by the formation of heterochromatically staining regions, or H-segments, which contain the chromatin to be lost. The removal of H-segments during diminution also must represent a major restructuring of the chromosomes which contained them. In order to examine the effects of diminution on the morphology and structure of the chromosomes, the C-banding technique was used. This procedure revealed that most C-bands present in the pre-diminution complement were absent in the post-diminution set. Additionally, in order to explore further the possible composition of the DNA contained in H-segments, a comparison, based on the relationship of C-bands to highly-repetitive DNA in chromosomes, was made between pre-diminution C-bands and H-segments. This comparison showed that not all H-segments are at chromosomal locations which produce a C-band, indicating that H-segments are perhaps not entirely composed of genetically inert DNA, as is currently supposed.

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The Differentiation of Germ and Somatic Cell Lines in Nematodes

Cited by 76 publications

References 184 publications

Evidence for Endoreduplication: Germ Cell DNA Levels Prior to Chromatin Diminution in Mesocyclops edax

Evidence for Endoreduplication: Germ Cell DNA Levels Prior to Chromatin Diminution in Mesocyclops edax

Isolation of a new germ line-specific repetitive DNA family in <i>Acricotopus</i> by microdissection of polytenized germ line-limited chromosome sections from a permanent larval salivary gland preparation

The effects of chromatin diminution on the pattern of C-banding in the chromosomes of Acanthocyclops vernalis Fischer (Copepoda: Crustacea)

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