Variability of 18rDNA loci in four lace bug species (Hemiptera, Tingidae) with the same chromosome number

Natalia V Golub,Victor B Golub,Valentina G Kuznetsova

doi:10.3897/compcytogen.v9i4.5376

Abstract

Male karyotypes of Elasmotropis testacea (Herrich-Schaeffer, 1835), Tingis cardui (Linnaeus, 1758), Tingis crispata (Herrich-Schaeffer, 1838), and Agramma femorale Thomson, 1871 (Heteroptera, Cimicomorpha, Tingidae) were analyzed using conventional chromosome staining and FISH with 18S rDNA and (TTAGG)n telomeric probes. The FISH technique was applied for the first time in the Tingidae. In spite of the fact that all species showed the same chromosome number (2n = 12 + XY), they have significant differences in the number and position of rDNA loci. FISH with the classical insect (TTAGG)n probe produced no signals on chromosomes suggesting telomeres in lace bugs to be of some other molecular composition. Tingidae share absence of the (TTAGG)n telomeric sequence with all so far studied taxa of the advanced true bug infraorders Cimicomorpha and Pentatomomorpha.

Highlights

Tingidae are a large widespread family of herbivorous bugs including 2200 species belonging to 280 genera
We describe the karyotypes of Elasmotropis testacea (Herrich-Schaeffer, 1835), Tingis cardui (Linnaeus, 1758), T. crispata (Herrich-Schaeffer, 1838), and Agramma femorale Thomson, 1871 after fluorescence in situ hybridization (FISH) with an 18S rDNA probe
At first metaphase subjected to 18S rDNA FISH, eight elements were present, including six autosomal bivalents which formed a ring with a pseudobivalent of the X and Y chromosomes located in its center

Summary

Introduction

Tingidae (lace bugs) are a large widespread family of herbivorous bugs including 2200 species belonging to 280 genera. With the use of C-banding technique, Grozeva and Nokkala (2001) were successful in identifying separate chromosomes in 13 lace bugs species and revealing differences between them in C-band pattern. These findings showed that C-heterochromatin distribution has had a major role in the karyotype evolution of the family Tingidae. Fluorescence in situ hybridization (FISH) has increased the resolution of the true bugs’ cytogenetics. Thanks to this technique, the analysis of the karyotypes has become more informative and comprehensive. Previous studies on species of two cimicomorphan families (Miridae and Cimicidae) showed the absence of this telomeric repeat (Frydrychová et al 2004, Grozeva et al 2011)

Material and methods

Results

Discussion