Cytogenetic Studies in Gomphocerine Grasshoppers. I. Comparative Analysis of Chromosome C-Banding Pattern
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Heredity 56 (1986) 365—372 The Genetical Society of Great Britain Received 18 September 1985 Cytogenetic studies in gomphocerine grasshoppers. I. Comparative analysis of chromosome C-banding pattern J. Cabrero and J. P. M. Camacho Departamento de Genética, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain. Chromosome C-banding pattern have been studied in 20 species of gomphocerine grasshoppers. Paracentromeric C- bands were present in the chromosomes of all species analysed, which favours the equilocal model of heterochromatin distribution. Interstitial or distal C-bands, on the other hand, appeared, at most, in two different chromosome pairs within the same chromosome complement, which is not expected on the equilocal model. Interspecific comparisons of C-banding patterns reveal the existence of differences between species of either the same or of different genera, which emphasises the dynamic nature of heterochromatin. The X chromosome shows more similarities for C-banding between the species of the genera Stenobothrus, Euchorthippus, and Omocestus than between these species and those of Chorthippus, which seem to indicate the existence of a close relationship between these three genera. INTRODUCTION caught in the South of the Iberian Peninsula, and belong to the subfamily Gomphocerinae (Orthop- Acrididgrasshoppers are very uniform in chromo- tera, Acrididae). They include representatives of some form and number (John and Hewitt, 1966). 20 species: specifically Truxalis nasuta (L.), For this reason this family has long been regarded Dociostaurus genei (Ocsk.), Ramburiella hispanica as chromosomally conservative since the majority (Ramb.), Euchorthippus chopardi Desc., E. pul- have 2n =22+XOc/XXtelo-subtelocentric vinatus (F.-W.), Stenobothrus festivus Bol., S. chromosomes. The Gomphocerinae is the most grammicus (Caz.), Omocestus bolivari Chop., 0. distinctive subfamily within the Acrididae since panteli (Bol.), 0. raymondi (Yers.), 0. !lorenteae about half of the species analysed to date have Stauroderus scalaris (F.-W.), Chorthippus 2n = Pasc., 16+XOd/XX9with three long metacentric parallelus (Zett.), Ch. dorsatus (Zett.), Ch. jucun- chromosome pairs which are presumed to have dus (Fisch.), Ch. apicalis (H.-S.), Ch. nevadensis arisen by centric fusions. Despite this apparent Pasc., Ch. binotatus (Charp.), Ch. vagans karyotypic conservatism, the Acrididae show (Eversm.) and Ch. brunneus (Thunb.). In all a extensive intraspecific variation for supernumerary total of 771 male and 334 female adults were ana- chromosome segments (John and King, 1977; lysed together with 697 embryos. 1982; 1983; Hewitt, 1979; Camacho et a!., 1984), Adult individuals were analysed cytologically as well as interspecific variation for C-banding by the methods described in Camacho and Cabrero (King and John, 1980; Santos et a!., 1983) and (1982). The embryos were studied cytologically nuclear DNA content (John and Hewitt, 1966; following the technique described by Webb et al. Kiknadze and Vysotskaya, 1969; Rees et a!., 1978; (1978), and C-banding was carried out as Gosálvez et a!., 1980). described in Camacho et a!. (1984). In this paper we analyse C-banding pattern in In all species analysed the autosomes have been 20 species of gomphocerine grasshoppers in order classified into three size groups: L (long), M to determine the interspecific differences which (medium) and S (short). exist between them. RESULTS MATERIALSAND METHODS Inthe majority of the 20 species analysed there Allthe individuals analysed in this report were were variations in the C-banding pattern involving 366 J. CABRERO AND J. P. M. CAMACHO the presence of supernumerary chromosome seg- extremes, though they may vary even between ments. These variations will be reported separately, different chromosomes of the same species. For and here we will consider the standard C-banding example, in Ramburiella hispanica (fig. 3) while pattern found in a majority of individuals within the four larger chromosome pairs have large para- the species analysed. centromeric C-bans the remainder have medium C-heterochromatin content and distribution in or small bands. In Omocestus panteli (fig. 9) para- the 20 species are shown in figs. 1-20 and table 1. centromeric C-bands are medium sized, with C-bands may show three different locations: para- exception of that in the S8 which is small. Chorthip- centromeric, interstitial and distal. Striking inter- pus apicalis (fig. 16) provides an extreme example specific differences exist for C-banding pattern in of the heterogeneous distribution of paracen- respect of the presence or absence of interstitial tromeric C-heterochromatin since it shows large and distal C-bands but more especially for the size C-bands in the L1, L2, L3, M6 and S8 chromosomes, of the paracentromeric bands. medium C-bands in the M7 and small C-bands in the X, M4 and M5. Other species show paracen- ParacentromericC-bands tromeric C-bands of medium size in all chromo- somes; this is so in Euchorthippus chopardi (fig. 4), Thechromosomes of all species analysed, like E. pulvinatus (fig. 5), Stenobothrusfestivus (fig. 6), those studied by King and John (1980) and Santos S. grammicus (fig. 7), Omocestus bolivari (fig. 8), et a!. (1983), have C-bands in the vicinity of the 0. llorenteae (fig. 11), Chorthippus parallelus (fig. centromeric regions. However, these paracen- 13), Ch.jucundus (fig. 15), Ch. nevadensis (fig. 17) tromeric C-bands may be small, representing and Ch. vagans (fig. 19). strictly centromeric heterochromatin, or large, in which case they are composed of both centric and interstitialC-bands proximal bands. The smallest centromeric C-bands occur in Omocestus raymondi (fig. 10) and Whileinterstitial bands are frequent in some Chorthippus dorsatus (fig. 14). Large compound species of Australian acridoids (King and John, paracentromeric C-bands are clearly exemplified 1980; John et aL, 1985) they are invariably scarce in Stauroderus scalaris (fig. 12), Chorthippus bino- in Spanish species (Santos et a!., 1983). In the tatus (fig. 18) and Ch. brunneus (fig. 20). In a present study we have observed them in 11 species majority of the species, however, paracentromeric but even here they never occur in more than two C-bands are intermediate between these two size chromosome pairs in any one species. A majority Table 1C-banding pattern in 20 species of gomphocerine grasshoppers Paracentromenc C-bands Interstitial Distal Species 2n Fig. Large Medium Small C-bands C-bands Dociostaurus genei 23 1 — L2-M4, M8 L1, M5-M7, X, M9-S11 L1 — Truxalis nasuta 23 2 — M9, 510 L1-M8, S11, X M9 M9 Ramburiella hispanica 23 3 L1M4 M5-S11, X — — — Euchorthippus chopardi 17 4 — All — X L3 Euchorthippus pulvinatus 17 5 — All — M6 — Stenobothrusfestivus 17 6 — All — — M6 Stenobothrus grammicus 17 7 — All — — — Omocestus bolivari 17 8 — All — — X Omocestus panteli 17 9 — All except S8 S8 L3 — Omocestus raymondi 17 10 — — All X L2, L3 Oinocestus llorenteae 17 11 — All — X — Stauroderus scalaris 17 12 All — — — — Chorthippus parallelus 17 13 — All — — L3 Chorthippus dorsatus 17 14 — — All — — Chorthippusjucundus 17 15 — All — L2, L3 — Chorthippus apicalis 17 16 L1-L3, M6, S0 M7 M4, M5, X — M Chorthippus nevadensis 17 17 — All — L2 M6, M7 Chorthippus binotatus 17 18 All — — — — Chorthippus vagans 17 19 — All — L2, L3 M4 Chorthippus brunneus 17 20 All — — L2, L3 M7 (fig. 15),Ch. vagans(fig.19)andCh. brunneus panteli (fig.9) andtheL2L3ofCh.jucundus of Chorthippus nevadensis(fig.17),the L3of0. and theXchromosomes.This includestheXof of interstitialC-bandsarelocated inthelong(L) Figures CYTOGENETIC STUDIESINGOMPHOCERINEGRASSHOPPERS.I mondi (fig.10)and0.llorenteae (fig.11),theL2 Euchorthippus chopardi(fig. 4),Omocestusray- (2) Truxalisnasuta,(3)Ramburiellahispanica,(4)Euchorthippuschopardi, (5)E.pulvinatus. a (4 -& 1—5 C-bandingpatterninthehaploidchromosomecomplementsof gomphocerinegrasshoppers.(1)Dociostaurusgenei, a°"e r S r • r C 4Sr W r r p.) ¼ • 4 inSantosand Giráldez,1982). chromosomes, isclearlyinterstitial(seefigs. 3and apparently distal C-bandwhich,inlesscondensed Euchorthippus pulvinatus (fig.5)possessesan and, finally,themegameric M6chromosomeof (fig. 20).Themegameric M9chromosomeof Truxalis nasuta(fig.2)has aninterstitialC-band 1:: 4.. — S - -4 -l UI 0 0 ee1 al S S 1 •2 0 0 0 0 367 Figures 368 (7) S.grammicus, (8)Omocestusbolivari,(9)0.panteli, (10)0.raymondi. 6—16 C-bandingpatterninthehaploid chromosomecomplementsofgomphocerinegrasshoppers.(6) Stenobothrusfestivus, -4 0 0 a —r S -t - S St I;. 4: S I C 'C 'C a a p J. CABREROANDP.M.CAMACHO 1. 0 S 9 4 3 I,) Figures 11—15 CYTOGENETIC STUDIESINGOMPHOCERINEGRASSHOPPERS.I -s - a -& C-banding pattern inthehaploidchromosomecomplements ofgomphocerinegrasshoppers. (11)Omocestusllorenteae, • 4 r (12) Stauroderus a r art • n. scalaris, (13)Chorthippus parallelus,(14)Ch.dorsatus, (15)Ch.jucundus. '4r S tie jS a • "I • S IC • • S -F - S a 'I), p 369 370 Figures (17) Ch. a -J a 16—20 C-banding patterninthehaploidchromosome complementsofgomphocerine grasshoppers. (16)Chorthippusapicalis, 0 - nevadensis, Sb r (18) Ch.binotatus, (19)Ch.vagans,(20)brunneus. ect .t fl • t a p__ a 3' -Se S S a —. a, a e jfr9 e - J. CABREROANDP.M.CAMACI-10 'a p. 1 a 'S 1 S CYTOGENETIC STUDIES IN GOMPHOCERINE GRASSHOPPERS. I 371 Distal C-bands limited by the fact that one cannot be sure that chromosomes of similar relative length are Theseare as infrequent as the interstistial C-bands and, like them, appear at most in two chromosome necessarily homologous in all genomes