Meiotic Pairing and Chiasma Localization in<i>Scyllina Signatipennis</i>(Gomphocerinae, Acrididae)

Bidau, Claudio J.

doi:10.1080/00087114.1984.10797688

Cited by 8 publications

(7 citation statements)

References 31 publications

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“…In Neotropical species, however, chromosome 9 is a consensus NOR location since it was observed in all five species analyzed by us, coinciding only with T. nasuta. In addition, the L 3 and X chromosomes harbour NORs in Scyllina signatipennis (Bidau 1984), in coincidence with R hispanica. On the other hand, the M 4 and M 6 locations observed in R. brasiliensis were not present in any of the three Palearctic species analyzed.…”

Section: Discussionmentioning

confidence: 96%

“…Two chromosomal races have been described in Sinipta dalmani, one with 2n = 23,24 X0:XX (Mesa et al 1982) and the other with 2n = 22,XY:XX arising from an X-autosome centric fusion (Remis 1993). Despite the high degree of karyotypic conservation observed among Neotropical gomphocerines, B chromosome polymorphisms are frequent (Bidau 1984;Vilardi 1986;Colombo and Remis 1997). Furthermore, a diagnostic karyotypic marker frequently found in different species of gomphocerines corresponds to the megameric chromosome (Cabrero and Camacho 1986;Remis 1989).…”

Section: Introductionmentioning

confidence: 95%

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Comparative analysis of rDNA location in five Neotropical gomphocerine grasshopper species

et al. 2007

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We report here, for the first time, the chromosome complement, number and location of the nucleolar organizer regions (NORs) revealed by silver staining (AgNO(3)) and fluorescent in situ hybridization (FISH) in five Neotropical gomphocerine species: Rhammatocerus brasiliensis, R. brunneri, R. palustris, R. pictus and Amblytropidia sp. The objective of this study was to summarize available data and propose a model of chromosome evolution in Neotropical gomphocerines. All five species studied showed chromosome numbers consisting of 2n = 23,X0 in males and 2n = 24,XX in females. Amblytropidia sp. was the only species showing a bivalent (M(8)) with megameric behavior during meiosis. The rDNA sites were restricted to autosomal pairs, i.e. the pericentromeric region of the S(9) chromosome, the consensus NOR location in all five species. R. brasiliensis was the only species showing additional NORs on M(4) and M(6) pairs which, likewise the S(9) NOR, were active in all cells analyzed. Comparison of these results with those reported previously in Palearctic gomphocerine species suggests higher resemblance of Neotropical species with the Old World species also possessing 23/24 chromosomes. Evolutionary mechanisms responsible for the observed interspecific variation in NOR location in this group are discussed.

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Section: Discussionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 95%

Comparative analysis of rDNA location in five Neotropical gomphocerine grasshopper species

et al. 2007

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“…Among Neotropical gomphocerine grasshoppers, B chromosomes have been described in Euplectrotettix shultzi and E. conspersus (Vilardi 1986a), Amblytropidia australis (Remis 1989), Scyllina signatipennis (Bidau 1984), and Sinipta dalmani (Colombo & Remis 1997). In the last species, two types of B chromosomes were identified: a medium telocentric B (B T ) resembling the X chromosome and a minute B chromosome smaller than the small autosomal pair.…”

Section: Introductionmentioning

confidence: 98%

Possible autosomal origin of macro B chromosomes in two grasshopper species

et al. 2007

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The acrocentric macro B chromosomes of Rhammatocerus brasiliensis (Acrididae, Gomphocerinae) and Xyleus discoideus angulatus (Romaleidae, Romaleinae) are highly similar to the X chromosome in each species in terms of morphology, size, and pycnosis. However, the results of FISH experiments using 45S and 5S rDNA probes suggest that in both species the B chromosomes are most likely of autosomal origin. In R. brasiliensis, the B chromosome presented 5S rDNA but not 45S rDNA, in resemblance to the L(2), L(3), M(5) and S(11) autosomes, but the X chromosome lacks both rDNA families. In X. d. angulatus, 45S rDNAs is absent from the B chromosome, whereas the X chromosome contains one of the two 45S rDNA clusters in the genome. The occurrence of B chromosomes in all nine R. brasiliensis populations analyzed indicates that they are widely distributed in Northeastern Brazil, and the small amount of interpopulation variation found for B chromosome prevalence suggests the existence of high gene flow, presumably due to the abundance of this grasshopper species on several types of vegetation and its relatively high flight capability.

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“…Other species such as the grasshoppers Chloealtis conspersa (Moens & Short 1983) and Euthystira brachyptera (Fletcher & Hewitt 1980) show pronounced localization of chiasmata but only semilocalized pairing. In P. conica the final extent of pairing is not a factor in the determination of chiasma position since complete SCs are observed at pachytene, a situation similar to those in Allium fistulosum (Albini & Jones 1987) and the grasshopper Scyllina signatipennis (Bidau 1984). pairing behavior of chromosomes during zygotene has been suggested (e.g.…”

Section: Discussionmentioning

confidence: 94%

Chiasma localization, heterochromatin and synaptonemal complexes in the grasshopperPyrgomorpha conica

1996

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Surface-spread synaptonemal complexes and chiasma distributions in spermatocytes with different C-banding patterns and chiasma distributions in oocytes were analyzed in the grasshopper Pyrgomorpha conica. Male meiosis was characterized by a proximal/distal chiasma localization and complete pairing of homologous chromosomes at pachytene. However, there were indications of a relationship between the frequency and location of pairing initiation sites and chiasma distribution. The presence of a proximal supernumerary segment in a medium-sized chromosome does not increase the mean cell chiasma frequency of carrier individuals compared with those lacking it but may modify chiasma distribution in at least some carrier bivalents. This effect could be related to heterosynapsis in the region near the segment. Mean cell chiasma frequency was significantly lower in females than in males. Females also showed altered chiasma distributions compared with males, with fewer proximal chiasmata and more interstitial and distal chiasmata.

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Meiotic Pairing and Chiasma Localization inScyllina Signatipennis(Gomphocerinae, Acrididae)

Cited by 8 publications

References 31 publications

Comparative analysis of rDNA location in five Neotropical gomphocerine grasshopper species

Comparative analysis of rDNA location in five Neotropical gomphocerine grasshopper species

Possible autosomal origin of macro B chromosomes in two grasshopper species

Chiasma localization, heterochromatin and synaptonemal complexes in the grasshopperPyrgomorpha conica

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