Recombination mapping of the Brazilian stingless bee Frieseomelitta varia confirms high recombination rates in social hymenoptera

Abstract

Background Meiotic recombination is a fundamental genetic process that shuffles allele combinations and promotes accurate segregation of chromosomes. Analyses of the ubiquitous variation of recombination rates within and across species suggest that recombination is evolving adaptively. All studied insects with advanced eusociality have shown exceptionally high recombination rates, which may represent a prominent case of adaptive evolution of recombination. However, our understanding of the relationship between social evolution and recombination rates is incomplete, partly due to lacking empirical data. Here, we present a linkage map of the monandrous, advanced eusocial Brazilian stingless bee, Frieseomelitta varia, providing the first recombination analysis in the diverse Meliponini (Hymenoptera, Apidae). Results Our linkage map includes 1417 markers in 19 linkage groups. This map spans approximately 2580 centimorgans, and comparisons to the physical genome assembly indicate that it covers more than 75 % of the 275 Megabasepairs (Mbp) F. varia genome. Thus, our study results in a genome-wide recombination rate estimate of 9.3–12.5 centimorgan per Mbp. This value is higher than estimates from nonsocial insects and comparable to other highly social species, although it does not support our prediction that monandry and strong queen-worker caste divergence of F. varia lead to even higher recombination rates than other advanced eusocial species. Conclusions Our study expands the association between elevated recombination and sociality in the order Hymenoptera and strengthens the support for the hypothesis that advanced social evolution in hymenopteran insects invariably selects for high genomic recombination rates.

Unexpectedly low recombination rates and presence of hotspots in termite genomes

“…Among Hymenoptera, the highest rates are found in the genus Apis : the Western honey bee Apis mellifera (20.8 cM/Mb) and its relatives Apis cerana (17.4 cM/Mb) Apis florea (20.8 cM/Mb) and Apis dorsata (25.1 cM/Mb) (Beye et al 2006; Shi et al 2013; Liu et al 2015; Wallberg et al 2015; Rueppell et al 2016; Kawakami et al 2019). Other social Hymenoptera also have high rates including the bumblebee Bombus terrestris (8.9) (Liu et al 2017; Kawakami et al 2019), the stingless bee Frieseomelitta varia (9.3 – 12.5 cM/Mb) (Waiker et al 2021), the wasp Vespula vulgaris (9.7 cM/Mb) (Sirviö et al 2011a) and the ants Pogonomyrmex rugosus (11.1 cM/Mb) (Sirviö et al 2011b) and Acromymex echinatior (6.1) (Sirviö et al 2006). In contrast, the solitary bee Megachile rotundata and the solitary wasp Nasonia have relatively low rates (1.0 and 1.5 cM/Mb respectively) (Niehuis et al 2010; Jones et al 2019).…”

“…Additionally, it has been proposed that high recombination rates could have facilitated the evolution of eusociality over a longer evolutionary timescale, because recombination between genes that take on functions in different castes permits them to evolve more independently (Kent and Zayed 2013). Several studies have addressed these hypotheses (Kent et al 2012; Liu et al 2015; Wallberg et al 2015; Rueppell et al 2016; Liu et al 2017; Jones et al 2019; Waiker et al 2021; Kawakami et al 2019) but so far none is strongly supported. It is also not clear whether eusociality per se selects for higher recombination rates, or whether high rates are a specific feature of eusocial Hymenoptera.…”

Understanding genome composition of eusocial hymenopteran insects

“…Unfortunately, the recombination rate of M. quadrifasciata is not known. The rate of another species of the Meliponini tribe, Friesomelitta varia, which has a comparable colony size range of 800-1600 (Tóth et al, 2004), is 12.5 cm/Mb (Waiker et al, 2021), indicating that the Meliponini tribe does include species with high recombination rates. However with an approximate 54 MY divergence time of the between Melipona and Friesomelitta (Cardinal & Danforth, 2013), it is not certain whether M. quadrifasciata also has a high recombination rate.…”