Biology subjects

Genevcius, B. C.

Publications and source records attributed to Genevcius, B. C..

3 recordsLinked to original sources

bioRxiv2022

Molecular and developmental signatures of genital size macro-evolution in bugs

With the advance of the evo-devo research program, our understanding of the genes and pathways that determine the architecture of novel traits has experienced drastic growth. Nevertheless, single-species approaches are insufficient to understand the processes by which evolution shapes morphological changes after their emergence. As such, we still have an elusive knowledge of how these genetic-developmental architectures evolve themselves for most of the structures, as well as how their evolution is mirrored in the phenotypic change across large time scales. Here, we tackle this gap by reconstructing the evolution of male genital size, one of the most complex traits in insects, together with its underlying genetic architecture. Using the order Hemiptera as a model, which spans over 350 million years of evolution, we estimate the correlation between genital size and three features: development rate, body size, and rates of DNA substitution in 68 genes previously associated with genital development. We demonstrate that genital size macro-evolution has been largely dependent on body size and weakly influenced by development rate and the phylogenetic history. Our results further revealed positive correlations between mutation rates and genital size for 18 genes. Interestingly, there is great diversity in the function of these genes, in the signaling pathways that they participate in, and in the specific genital parts that they control. These results suggest that fast genital size evolution has been enabled by molecular changes associated with diverse morphogenetic processes, such as cuticle composition, patterning of sensory apparatus, and organ growth itself. Our data further demonstrate that the majority of DNA evolution correlated with the genitalia has been shaped by negative selection or neutral evolution. This indicates that genital changes are predominantly facilitated by relaxation of constraints rather than positive selection, possibly due to the high pleiotropic nature of the morphogenetic genes.

evolutionary biology↗

bioRxiv2020

De novo construction of a transcriptome for the stink bug crop pest Chinavia impicticornis during late development

Chinavia impicticornis is a Neotropical stink-bug (Hemiptera: Pentatomidae) with economic importance for different crops. Little is known about the development of the species, as well as the genetic mechanisms that may favor the establishment of populations in cultivated plants. Here we conduct the first large-scale molecular study with C. impicticornis. We generated RNA-seq data for males and females, at two immature stages, for the genitalia separately and for the rest of the body. We assembled the transcriptome and conduct a functional annotation. De novo assembled transcriptome based on whole bodies and genitalia of males and females contained around 400,000 contigs with an average length of 688 bp. After pruning duplicated sequences and conducting a functional annotation, the final annotated transcriptome comprised 39,478 transcripts of which 12,665 had GO terms assigned. These novel datasets will provide invaluable data for the discovery of molecular processes related to morphogenesis and immature biology. We hope to contribute to the growing research on stink bug evo-devo as well as the development of bio-rational solutions for pest management.

genomics↗

bioRxiv2020

Phylogeny of the stink bug tribe Chlorocorini (Heteroptera, Pentatomidae) based on DNA and morphological data

Pentatomidae is the third largest family of true bugs, comprising over 40 tribes. Few tribes have been studied in a phylogenetic context, and none of them have been examined using molecular data. Moreover, little is known about the evolution of key morphological characters widely used in taxonomic and phylogenetic studies at multiple levels. Here, we conduct a phylogenetic study of the tribe Chlorocorini (Pentatominae) combining 69 morphological characters and five DNA loci. We use the inferred phylogeny to reconstruct the evolution of key morphological characters such as the spined humeral angles of the pronotum, a dorsal projection on the apices of the femora and characters of male genitalia. We provide solid evidence that the tribe as currently recognized is not monophyletic based both on DNA and morphological data. The genera Arvelius Spinola and Eludocoris Thomas were consistently placed outside of the Chlorocorini, while the remaining genera were found to form a monophyletic group. We also show that nearly all morphological diagnostic characters for the tribe are homoplastic. The only exception is the development of the hypandrium, which, contrary to expectations for genital traits, showed the slowest evolutionary rates. In contrast, the most rapidly evolving trait is the length of the ostiolar ruga, which may be attributed to selection favoring anti-predatory behavior and other functions of its associated scent glands. Lastly, we also provide a preliminary glimpse of the main phylogenetic relationships within the Pentatomidae, which indicates that most of the included subfamilies and tribes are not monophyletic. Our results suggest that the current subfamily-level classification of Pentatomidae is not adequate to reflect its evolutionary history, and we urge for a more complete phylogeny of the family.

zoology↗