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

Abstract

Although many species of the genus Trigona have been taxonomically described, cytogenetic studies of these species are still rare. The aim of the present study was to obtain cytogenetic data by conventional staining, C banding and fluorochrome staining for the karyotype characterization of the species Trigona fulviventris. Cytogenetic analysis revealed that this species possesses a diploid chromosome number of 2n = 32, different from most other species of this genus studied so far. This variation was probably due to the centric fusion in a higher numbered ancestral karyotype, this fusion producing the large metacentric chromosome pair and the lower chromosome number observed in Trigona fulviventris. Heterochromatin was detected in the pericentromeric region of the first chromosome pair and in one of the arms of the remaining pairs. Base-specific fluorochrome staining with 4'-6-diamidino-2-phenylindole (DAPI) showed that the heterochromatin was rich in AT base pairs (DAPI + ) except for pair 13, which was chromomycin A 3 (CMA 3 ) positive indicating an excess of GC base pairs. Our data also suggests that there was variation in heterochromatin base composition.

Heterochromatin Distribution and Chromosomal Mapping of Microsatellite Repeats in the Genome ofFrieseomelittaStingless Bees (Hymenoptera: Apidae: Meliponini)

“…The diploid number found for all species in this study support the conservative evolution of chromosomal numbers in Frieseomelitta, even though most trigonines have 2n = 34, except for Trigona fulviventris (Hymenoptera: Apidae) (2n = 32) (Rocha et al 2003;Domingues et al 2005;Miranda et al 2013;Godoy et al 2013).…”

The evolution of haploid chromosome numbers in Meliponini

“…[44]) with 2 n = 32 chromosomes, unlike the other Trigona species with 2 n = 34. This reduction of the chromosome number is the result of centric fusion of two pseudoacrocentric chromosomes, which generated a larger metacentric chromosome with heterochromatin restricted to the pericentromeric region [44].…”

Molecular characterization of constitutive heterochromatin in three species of Trypoxylon (Hymenoptera, Crabronidae, Trypoxylini) by CMA3/DAPI staining

“…Intraspecific variation in heterochromatin base composition has already been detected in other studies. For example, Domingues et al (2005) detected a single chromosome pair with GC-rich heterochromatin in contrast with all the remaining AT-rich chromosomes in Trigona fulviventris Guérin, 1835 using C-banding and fluorochrome staining. Together with the previously described karyotypes, our results document a high frequency of large pseudoacrocentric chromosomes in Neotropical Trypoxylon species.…”