Fax +41 61 306 12 34 E-Mail karger@karger.ch www.karger.com Original Article Cytogenet Genome Res 2012;138:36–45 DOI: 10.1159/000341571 Chromosomal Localization of Ribosomal and Telomeric DNA Provides New Insights on the Evolution of Gomphocerinae Grasshoppers I.E. Jetybayev a, b A.G. Bugrov b, c T.V. Karamysheva a J.P.M. Camacho d N.B. Rubtsov a, c a Institute of Cytology and Genetics, and b Institute of Systematics and Ecology of Animals, SB RAS, and c Novosibirsk State University, Novosibirsk, Russia; d Departamento de Genetica, Facultad de Ciencias, Universidad de Granada, Granada, Spain a single rDNA cluster in the longest autosome. Telomeric re- peats were located primarily on the ends of chromosome arms. In 2 species, however, we observed the presence of interstitial clusters outside telomeric regions. The first one, Aeropus sibiricus, exhibited a polymorphic interstitial site of telomeric repeats in chromosome 6 as a consequence of a paracentric inversion. Most remarkably, Chorthippus jacob- soni showed the presence of telomeric repeats in the peri- centric regions of the 3 biarmed chromosome pairs originat- ed by centric fusion, thus suggesting that these rearrange- ments were not of the Robertsonian type but true centric fusion with a probable generation of dicentric chromo- somes . Copyright © 2012 S. Karger AG, Basel Cytological analysis has shown that the extensive tax- onomic diversity of Gomphocerinae grasshoppers is characterized by high karyotypic conservatism. The dip- loid chromosome number usually varies from 23–17 in males (sex determination being X0 male/XX female) as a result of 3 Robertsonian translocations yielding 3 large metacentric chromosome pairs [Robertson, 1916; White, 1973; Hewitt, 1979]. Limited capacity of the linear differ- entiation of chromosomes does not allow specifying the Key Words Chromosomes  Gomphocerinae grasshoppers  Karyotype evolution  rDNA  Telomeric repeats Abstract Chromosome location of ribosomal DNA (rDNA) and telo- meric repeats was analysed in mitotic chromosomes of 15 species of Gomphocerinae grasshoppers belonging to the tribes Arcypterini, Gomphocerini, Stenobothrini, and Chry- sochraontini. Two types of rDNA distribution were found in the Gomphocerini tribe. Type 1, found in 9 species, was char- acterized by the presence of rDNA in the short arm of the long biarmed chromosomes 2 and 3 and, in some species, also in the X chromosome. Type 2 was found only in Aeropus sibiricus and Stauroderus scalaris and consisted in the pres- ence of pericentromeric rDNA blocks in all chromosomes. A comparison of rDNA distribution in Gomphocerini species with 2n - = 23, 2n - = 21, and 2n - = 17 suggested the pos- sible involvement of chromosome 6 in the ancestral karyo- type (2n - = 23) in 1 of the 3 centric fusions that decreased the chromosome number in these species. In the tribe Stenobothrini, Stenobothrus eurasius carried a single rDNA cluster in the X chromosome, likewise 2 Spanish species pre- viously analysed, but Omocestus viridulus unusually showed Accepted: June 6, 2012 by M. Schmid Published online: August 22, 2012 I.E. Jetybayev Institute of Cytology and Genetics, SB RAS 10 Lavrentiev Ave. RU–630090 Novosibirsk (Russia) Tel. +7 951 376 1848, E-Mail jetybayev  @  mail.ru © 2012 S. Karger AG, Basel 1424–8581/12/1381–0036$38.00/0 Accessible online at: www.karger.com/cgr