Comparative molecular cytogenetics in five species of stingless bees (Hymenoptera, Apidae)

Abstract

Repetitive DNA sequences constitute a large portion of the eukaryotic genome. Despite their importance, only a few Meliponini species, especially those from the Melipona Illiger, 1806 genus, had some microsatellite sequences and the rDNA genes physically mapped. Therefore, in order to expand our knowledge on this genomic component of neotropical bees, in the present study we investigated the distribution of microsatellite sequences, including the telomeric repeat (TTAGG)6 and rDNA clusters, in the chromosomes of five stingless species, Cephalotrigona capitata (Smith, 1854), Partamona auripennis Pedro & Camargo, 2003, P. cupira (Smith, 1863), P. helleri (Friese 1900), and Tetragona elongata (Lepeletier & Serville, 1828). The microsatellite probes (GA)15, (GAG)10, and (CAA)10, revealed hybridization signals in the euchromatic regions of most chromosome pairs. The (GAG)10 probe, however, also yielded a positive signal in the heterochromatic arm of one chromosome pair of T. elongata. The telomeric (TTAGG)6 sequence hybridized to the ends of chromosome pairs, while signals for the 18S rDNA probe varied among the species. Here was demonstrated the karyotypic diversity that exists among five species of stingless bees in terms of repetitive sequences. These cytogenetic marker provides new information about the chromatin composition and rDNA cluster locations for five Meliponini species (three genera) and highlights the contribution of repetitive sequences to the karyotypic evolution of this tribe.