DNA characterization and karyotypic evolution in the bee genus Melipona (Hymenoptera, Meliponini)

Abstract

We analyzed patterns of heterochromatic bands in the Neotropical stingless bee genus Melipona (Hymenoptera, Meliponini). Group I species (Melipona bicolor bicolor, Melipona quadrifasciata, Melipona asil6ae, Melipona marginata, Melipona subnitida) were characterized by low heterochromatic content. Group II species (Melipona capixaba, Melipona compressipes, Melipona crinita, Melipona seminigra fuscopilosa e Melipona scutellaris) had high heterochromatic content. All species had 2n =18 and n = 9. In species of Group I heterochromatin was pericentromeric and located on the short arm of acrocentric chromosomes, while in Group II species heterochromatin was distributed along most of the chromosome length. The most effective sequential staining was quinacrine mustard (QM)/distamycin (DA)/chromomycin A 3 (CMA 3 )/4-6-diamidino-2-phenylindole (DAPI). Heterochromatic and euchromatic bands varied extensively within Group I. In Group II species euchromatin was restricted to the chromosome tips and it was uniformly GC + . Patterns of restriction enzymes (EcoRI, DraI, HindIII) showed that heterochromatin was heterogeneous. In all species the first pair of homologues was of unequal size and showed heteromorphism of a GC + pericentromeric heterochromatin. In M. asil6ae (Group I) this pair bore NOR and in M. compressipes (Group II) it hybridized with a rDNA FISH probe. As for Group I species the second pair was AT + in M. subnitida and neutral for AT and GC in the remaining species of this group. Outgroup comparison indicates that high levels of heterochromatin represent a derived condition within Melipona. The pattern of karyotypic evolution sets Melipona in an isolated position within the Meliponini.

Similarity of heterochromatic regions in the stingless bees (Hymenoptera: Meliponini) revealed by chromosome painting

“…The information available about heterochromatin in bees is usually restricted to its distribution based on C-banding and its base richness based on fluorochrome staining (Rocha et al 2002;Brito et al 2005;Lopes et al 2011). Therefore, other aspects such as inter and intraspecific homologies have not been studied yet because of limitations of the conventionally used techniques.…”

Karyotype characterization of Trigona fulviventris Guérin, 1835 (Hymenoptera, Meliponini) by C banding and fluorochrome staining: report of a new chromosome number in the genus

“…Published data regarding the cytogenetics of Meliponini have indicated that the haploid number ranges from 8 to 18 chromosomes, although the predominant number is n = 17 (Kerr, 1952(Kerr, , 1972Kerr and Silveira, 1972;Tarelho, 1973;Hoshiba, 1988;Alves, 1999;Rocha et al, 2002). Kerr (1972), Kerr and Silveira (1972) and Tarelho (1973) have raised the hypothesis of polyploidy to explain the numerical changes observed in the karyotypes of these bees.…”

An optimized method for the generation of AFLP markers in a stingless bee (Melipona quadrifasciata) reveals a high degree of intracolonial genetic polymorphism

“…The significant contribution of workers to male production in many stingless bee species (Tóth et al, 2002(Tóth et al, , 2004Paxton et al, 2003;Velthuis, 2005) in conjunction with a high recombination frequency could represent mechanims that allow maintenance of sufficiently high genetic diversity in even relatively small populations of stingless bees. Even though high recombination rates have so far only been demonstrated for honey bees (Hunt and Page, 1995;Gadau et al, 2001), studies on karyotype (Rocha et al, 2002) and mitochondrial genome evolution (Weinlich et al, 2004;Arias et al, 2006) suggest that stingless bees could harbor rather flexible genomes, as well.…”