An association between Dnmt1 and Wnt in the production of oocytes in the whitefly Bemisia tabaci.

The function of DNA methylation in insects and the DNA methyltransferase (Dnmt) genes that influence methylation remains uncertain. We used RNA interference to reduce the gene expression of Dnmt1 within the whitefly Bemisia tabaci (Hemiptera:Aleyrodidae; Gennadius), a hemipteran species that relies on Dnmt1 for proper gametogenesis. We then used RNA-seq to test an a priori hypothesis that meiosis-related genetic pathways would be perturbed.

gene expression is associated with temporal kin recognition.

A key component of parental care is avoiding killing and eating one's own offspring. Many organisms commit infanticide but switch to parental care when their own offspring are expected, known as temporal kin recognition. It is unclear why such types of indirect kin recognition are so common across taxa.

The role of Dmnt1 during spermatogenesis of the insect Oncopeltus fasciatus.

Background: The function of DNA methyltransferase genes of insects is a puzzle, because an association between gene expression and methylation is not universal for insects. If the genes normally involved in cytosine methylation are not influencing gene expression, what might be their role? We previously demonstrated that gametogenesis of Oncopeltus fasciatus is interrupted at meiosis following knockdown of DNA methyltransferase 1 (Dnmt1) and this is unrelated to changes in levels of cytosine methylation. Here, using transcriptomics, we tested the hypothesis that Dmnt1 is a part of the meiotic gene pathway.

Insect homolog of oxytocin/vasopressin associated with parenting of males but not females in a subsocial beetle.

Parental care is thought to evolve through modification of behavioral precursors, which predicts that mechanistic changes occur in the genes underlying those traits. The duplicated gene system of oxytocin/vasopressin has been broadly co-opted across vertebrates to influence parenting, from a preduplication ancestral role in water balance. It remains unclear whether co-option of these genes for parenting is limited to vertebrates.

The role of Dnmt1 in oocyte development.

The whitefly Bemisia tabaci is a globally important crop pest that is difficult to manage through current commercially available methods. While RNA interference (RNAi) is a promising strategy for managing this pest, effective target genes remain unclear. We suggest DNA methyltransferase 1 (Dnmt1) as a potential target gene due to its effect on fecundity in females in other taxa of insects.

Gene expression underlying parenting and being parented shows limited plasticity in response to different ambient temperatures.

Flexible interactions between parents and offspring are essential for buffering families against variable, unpredictable, and challenging environmental conditions. In the subsocial carrion beetle, Nicrophorus orbicollis, mid-summer temperatures impose steep fitness costs on parents and offspring but do not elicit behavioural plasticity in parents. Here, we ask if plasticity of gene expression underpins this behavioural stability or facilitates independent compensation by larvae.

Survey of neurotransmitter receptor gene expression into and out of parental care in the burying beetle .

Understanding the genetic influences of traits of nonmodel organisms is crucial to understanding how novel traits arise. Do new traits require new genes or are old genes repurposed? How predictable is this process? Here, we examine this question for gene expression influencing parenting behavior in a beetle, . Parental care, produced from many individual behaviors, should be influenced by changes of expression of multiple genes, and one suggestion is that the genes can be predicted based on knowledge of behavior expected to be precursors to parental care, such as aggression, resource defense, and mating on a resource.

The essential role of Dnmt1 in in the large milkweed bug .

Given the importance of DNA methylation in protection of the genome against transposable elements and transcriptional regulation in other taxonomic groups, the diversity in both levels and patterns of DNA methylation in the insects raises questions about its function and evolution. We show that the maintenance DNA methyltransferase, DNMT1, affects meiosis and is essential to fertility in milkweed bugs, , while DNA methylation is not required in somatic cells. Our results support the hypothesis that is required for the transition of germ cells to gametes in and that this function is conserved in male and female gametogenesis.

Evolution of Personal and Social Immunity in the Context of Parental Care.

Social immunity moderates the spread of pathogens in social groups and is especially likely in groups structured by genetic relatedness. The extent to which specific immune pathways are used is unknown. Here, we investigate the expression and social role of three functionally separate immune genes (pgrp-sc2, thaumatin, and defensin) during parental care in the beetle Nicrophorus vespilloides.

Variation in mandible development and its relationship to dependence on parents across burying beetles.

Background: In species with parental care, there is striking variation in offspring dependence at birth, ranging from feeding independence to complete dependency on parents for nutrition. Frequently, highly dependent offspring further evolve reductions or alterations of morphological traits that would otherwise promote self-sufficiency. Here, we examine evidence for morphological evolution associated with dependence in burying beetles ( spp.

Dnmt1 is essential for egg production and embryo viability in the large milkweed bug, Oncopeltus fasciatus.

Background: The function of cytosine (DNA) methylation in insects remains inconclusive due to a lack of mutant and/or genetic studies.

Results: Here, we provide evidence for the functional role of the maintenance DNA methyltransferase 1 (Dnmt1) in an insect using experimental manipulation. Through RNA interference (RNAi), we successfully posttranscriptionally knocked down Dnmt1 in ovarian tissue of the hemipteran Oncopeltus fasciatus (the large milkweed bug).

Changes of gene expression but not cytosine methylation are associated with male parental care reflecting behavioural state, social context and individual flexibility.

Behaviour is often a front line response to changing environments. Recent studies show behavioural changes are associated with changes of gene expression; however, these studies have primarily focused on discrete behavioural states. We build on these studies by addressing additional contexts that produce qualitatively similar behavioural changes.

Changes in chromatin accessibility between Arabidopsis stem cells and mesophyll cells illuminate cell type-specific transcription factor networks.

Cell differentiation is driven by changes in the activity of transcription factors (TFs) and subsequent alterations in transcription. To study this process, differences in TF binding between cell types can be deduced by probing chromatin accessibility. We used cell type-specific nuclear purification followed by the assay for transposase-accessible chromatin (ATAC-seq) to delineate differences in chromatin accessibility and TF regulatory networks between stem cells of the shoot apical meristem (SAM) and differentiated leaf mesophyll cells in Arabidopsis thaliana.

Duplication and Sub/Neofunctionalization of , an Insect Homolog of , in the Subsocial Beetle .

With growing numbers of sequenced genomes, increasing numbers of duplicate genes are being uncovered. Here we examine , a gene in the natural resistance-associated macrophage protein (Nramp) family, that has been duplicated in the subsocial beetle, , which exhibits advanced parental behavior. There is only one copy of in honey bees and Drosophila, whereas in vertebrates there are two copies that are subfunctionalized.

Relating quantitative variation within a behavior to variation in transcription.

Many studies have shown that variation in transcription is associated with changes in behavioral state, or with variation within a state, but little has been done to address if the same genes are involved in both. Here, we investigate the transcriptional basis of variation in parental provisioning using two species of burying beetle, Nicrophorus orbicollis and Nicrophorus vespilloides. We used RNA-seq to compare transcription in parents that provided high amounts of provisioning behavior versus low amounts in males and females of each species.

Difference in parenting in two species of burying beetle, and .

Burying beetles () are model parents among insects, with all studied species known to regurgitate flesh from vertebrate carcasses to their offspring. However, most studies focus on a very few species, yet the interpretation of the function and importance of care is typically generalized to all burying beetles. Here we characterize subtle variation within and between individuals and sexes, and how this variation differs between two species of burying beetle.

Adipocyte nuclei captured from VAT and SAT.

Background: Obesity-related comorbidities are thought to result from the reprogramming of the epigenome in numerous tissues and cell types, and in particular, mature adipocytes within visceral and subcutaneous adipose tissue, VAT and SAT. The cell-type specific chromatin remodeling of mature adipocytes within VAT and SAT is poorly understood, in part, because of the difficulties of isolating and manipulating large fragile mature adipocyte cells from adipose tissues.

Methods: We constructed MA-INTACT (Mature Adipocyte-Isolation of Nuclei TAgged in specific Cell Types) mice using the adiponectin (ADIPOQ) promoter (ADNp) to tag the surface of mature adipocyte nuclei with a reporter protein.

Subsets of Visceral Adipose Tissue Nuclei with Distinct Levels of 5-Hydroxymethylcytosine.

The reprogramming of cellular memory in specific cell types, and in visceral adipocytes in particular, appears to be a fundamental aspect of obesity and its related negative health outcomes. We explored the hypothesis that adipose tissue contains epigenetically distinct subpopulations of adipocytes that are differentially potentiated to record cellular memories of their environment. Adipocytes are large, fragile, and technically difficult to efficiently isolate and fractionate.

The role of neuropeptide F in a transition to parental care.

The genetics of complex social behaviour can be dissected by examining the genetic influences of component pathways, which can be predicted based on expected evolutionary precursors. Here, we examine how gene expression in a pathway that influences the motivation to eat is altered during parental care that involves direct feeding of larvae. We examine the expression of neuropeptide F, and its receptor, in the burying beetle Nicrophorus vespilloides, which feeds pre-digested carrion to its begging larvae.

The Genome and Methylome of a Beetle with Complex Social Behavior, Nicrophorus vespilloides (Coleoptera: Silphidae).

Testing for conserved and novel mechanisms underlying phenotypic evolution requires a diversity of genomes available for comparison spanning multiple independent lineages. For example, complex social behavior in insects has been investigated primarily with eusocial lineages, nearly all of which are Hymenoptera. If conserved genomic influences on sociality do exist, we need data from a wider range of taxa that also vary in their levels of sociality.

Transcriptomes of parents identify parenting strategies and sexual conflict in a subsocial beetle.

Parenting in the burying beetle Nicrophorus vespilloides is complex and, unusually, the sex and number of parents that can be present is flexible. Such flexibility is expected to involve specialized behaviour by the two sexes under biparental conditions. Here, we show that offspring fare equally well regardless of the sex or number of parents present.

Arabidopsis plants deficient in constitutive class profilins reveal independent and quantitative genetic effects.

Background: The actin cytoskeleton is involved in an array of integral structural and developmental processes throughout the cell. One of actin's best-studied binding partners is the small ubiquitously expressed protein, profilin. Arabidopsis thaliana is known to encode a family of five profilin sequence variants: three vegetative (also constitutive) profilins that are predominantly expressed in all vegetative tissues and ovules, and two reproductive profilins that are specifically expressed in pollen.

Vitellogenin and vitellogenin receptor gene expression is associated with male and female parenting in a subsocial insect.

Complex social behaviour in Hymenoptera has been hypothesized to evolve by co-opting reproductive pathways (the ovarian ground plan hypothesis, OGPH) and gene networks (the reproductive ground plan hypothesis, RGPH). In support of these hypotheses, in eusocial Hymenoptera where there is reproductive division of labour, the yolk precursor protein vitellogenin (Vg) influences the expression of worker social behaviour. We suggest that co-opting genes involved in reproduction may occur more generally than just in the evolution of eusociality; i.