Mitochondria are critical organelles in almost all eukaryotic cells in generating most of the chemical energy needed to power the cell's biochemical reactions. Mitochondria contain their own genomic sequences, mitogenomes, which are being widely used in species identification, phylogenetic, population genetics, and comparative genomics. However, largely are still unclear regarding to the structural variations of mitogenomes.

In a recent study conducted by the scientists from Xishuangbanna Tropical Botanical Garden of the Chinese Academy of Sciences, new mitogenome structures were discovered in the Meliponini.

In this study, the mitogenome variations and their phylogenetic signature over three social bee tribes, Apini (honeybees), Meliponini (stingless bees) and Bombini (bumblebees) were investigated. Taxa within these three tribes are iconic around the world for their roles in pollination and economic production, as well as their social behaviors. Comparative analyses basing on an extensive sampling regarding to 154 individuals, including 73 de novo assembled new mitogenomes and 81 previously reported mitogenomes were incorporated.

The main results of this study include that: 1) the mitogenomes of Apini and Bombini are the typical type, while those of Meliponini show diverse variations in mitogenome sizes and organizations. 2) Phylogenetic analyses support the Meliponini as sister to Bombini, and then the two tribes as sister to Apini. Molecular evolutionary genetics analysis show the potential effects of large inverted repeats on animal mitogenome evolution and confirm that Meliponini is a hotspot in mitogenome evolution.

Using low sampling size to represent the whole genus, tribe, family, or even order in mitogenomic studies could easily overlook potential variations at lower taxonomic levels, which might lead to some incorrect inferences. This study nicely demonstrated that comprehensive sampling is necessary to fully understand the patterns of mitogenome structure variations and their implications for phylogenetic inference.

This work, published in Zoological Research, was funded by the Strategic Priority Research Program of the Chinese Academy of Science, the Science and Technology Basic Resources Investigation Program of China, the Yunnan Revitalization Talent Support Program “Young Talent” and "Innovation Team" Projects, and the 14th Five-Year Plan of Xishuangbanna Tropical Botanical Garden, the Chinese Academy of Science. 

Lepidotrigona flavibasis and the hive (Image by Peng Zhang)

Contact:

Wenbin Yu 

Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences

Email: yuwenbin@xtbg.ac.cn