Autosomal rearrangement in Gryllus assimilis Fabricius, 1775 (Orthoptera, Gryllidae)

Abstract

Gryllus assimilis L. has a karyotype of 2n = 29 (X0, male) and 30 (XX, female). The above karyotype was encountered along with another in which 2n = 28 (X0, male) and 2n = 29 (XX, female) in a population from the outskirts of Rio Claro city (São Paulo State, Brazil). Of eight specimens studied, five had the heterozygous karyotype involving a translocation and three had the basic karyotype. There were no individuals homozygous for the rearrangement. The heterozygous karyotype was the result of a chromosomal rearrangement between chromosome pairs 6 and 10, both of which were initially submetacentric. The members of the sixth pair normally have two constrictions in the small arm, with a satellite at the chromosome tip. The chromosome of the tenth pair involved in the translocation was generally submetacentric and probably underwent a pericentric inversion which transported the centromere to a subterminal position before being translocated. In this case, the long arm of the inverted chromosome of the tenth pair was translocated with the satellite of a member of the sixth pair.<br>A espécie Gryllus assimilis L. apresenta 2n = 29, X0 (macho) e 2n = 30, XX (fêmea), porém em alguns indivíduos coletados na cidade de Rio Claro, São Paulo, Brasil, foram encontrados dois cariótipos distintos: o cariótipo básico e outro rearranjado, com 2n = 28, X0 e 2n = 29, XX. O rearranjo foi interpretado como sendo autossômico e heterozigoto, caracterizado pela translocação envolvendo dois pares de homólogos submetacêntricos: o par 10, que possivelmente tem um dos elementos com uma inversão pericêntrica, e o par 6, que possui em seu braço curto duas constrições secundárias, diferenciando satélites em suas extremidades

The characteristics of karyotype and telomeric satellite DNA sequences in the cricket, <i>Gryllus bimaculatus</i> (Orthoptera, Gryllidae)

“…campestris (Warchalowska-Sliwa, 1980) and G . assimilis (Zefa, 1999), secondary constriction regions were localized in the short arm of one autosome pair, and presumably correspond to NORs. Such distribution of NORs was also observed in Gymnogryllus minor (2n = 19/20) (Bhunya and Das, 1985) and Teleogryllus derelictus (2n = 27/28) (Yoshimura, unpublished).…”

Karyotypes of two American field crickets: Gryllus rubens and Gryllus sp. (Orthoptera: Gryllidae)

“…1). Variation of length in chromosomes with SC was also observed in a Brazilian population of G. assimilis (Fabricius), and the chromosome became larger by tandem fusion (Zefa 1999). The chromosome configuration and the C-banding patterns were different between the two Gryllus species examined.…”

“…In other Gryllus , G. bimaculatus samples collected in Berhampur, India are known to have NOR in one pair of autosomes (Das & Das 1992). Presumably, SC regions observed in chromosome 7 of Gryllus argentinus (de Saussure) (Drets & Stoll 1974) and Gryllus campestris (Linnaeus) (Warchałowska‐Śliwa 1980) and chromosome 6 of Gryllus assimilis (Fabricius) (Zefa 1999) are also the sites of NOR.…”

Path analysis of the genetic integration of traits in the sand cricket: a novel use of BLUPs

“…Gryllus have an XO (male), XX (female) sex‐determining system (Lim et al. , 1973; Zefa, 1999; note that in Lim et al. , G. firmus is given as G. bermudiensis ).…”

“…The trade-off of interest occurs between flight capability and reproduction in wing dimorphic insects, and our test species is the sand cricket, Gryllus firmus. Gryllus have an XO (male), XX (female) sex-determining system (Lim et al, 1973;Zefa, 1999; note that in Lim et al, G. firmus is given as G. bermudiensis). In contrast, the dimorphism in wing length is a consequence of a developmental switch that can occur as late as the last nymphal stadium and is best explained by the threshold model (Roff & Shannon, 1993;Fairbairn & Yadlowski, 1997).…”