Cytogenomics of Frieseomelitta varia (Hymenoptera: Apidae) and the Sharing of a Satellite DNA Family in Several Neotropical Meliponini Genera.

Abstract

Background/objectives: A striking feature of the karyotypes of stingless bees is the large amount of heterochromatin present in most species. Cytogenomic studies performed in some Meliponini species have suggested that evolutionary events related to the diversification and amplification of satellite DNA families in the heterochromatin may reflect the structuring of phylogenetic clades in this tribe. In this study, we performed a genomic analysis in Frieseomelitta varia to characterize different satDNA families in its genome. We also investigated the presence of the most abundant satDNA family of F. varia in its own chromosomes, in two other Frieseomelitta species, and in other Meliponini genera encompassing the three main clades of Neotropical Meliponini, according to the available molecular phylogeny.

Methods: Genomic analyses were performed using RepeatExplorer2 on the Galaxy platform, and chromosomal investigations were conducted using fluorescent in situ hybridization.

Results: Seven satDNA families were recovered, which together totaled an abundance of 11.223% of the analyzed F. varia genomic fraction. The most abundant satDNA family, FvarSat01-306, predominates in the analyzed repetitive fraction (representing around 89%) and was recently amplified and homogenized in almost all the heterochromatin of F. varia. In addition, the data revealed an unprecedented sharing of this satDNA family in the centromeric/pericentromeric heterochromatin among different Meliponini genera, with independent amplifications and loss of this sequence in some taxa.

Conclusions: One family of satellite DNA makes up most of the heterochromatin in this species and is shared with other Meliponini.