Biology subjects

Inbar, S.

Publications and source records attributed to Inbar, S..

7 recordsLinked to original sources

bioRxiv2025

Genetic basis of cuticular hydrocarbon variation in the desert ant

Cuticluar hydrocarbons (CHCs) are a ubiquitous component of insect cuticles that are used for a wide range of chemical signaling functions, especially recognition. Recognition and other signals are vital for the maintenance of insularity and cooperation in social insect colonies. Therefore, we expect natural selection on the composition and variabitlity of social insect CHC profiles. Selection on these signals may result in the evolution of genetic polymorphism affecting variation in CHC profiles. Here we tested for a genetic basis of CHC variation in the desert ant Cataglyphis niger. We applied a genomic mapping appraoch to a cohort of brothers from the same nest to reduce noise from environmental effects and achieve a clear statistical signal for association between the variation of CHCs and quantitative trait loci (QTL). This analysis identified 19 QTLs associated with 8 out of the 31 CHCs identified, and one QTL associated with total CHC quantity. These QTLs are located on 11 different chromosomes, including two cases where QTLs of different CHCs overlap. Each QTL explains between 13-25% of the variation in a specific CHC. We highlight several candidate genes in the QTLs identified, including fatty acid elongase and reductase genes. Our results reveal a polygenic genomic architecture underlying CHC variation in a population of the desert ant and open new research avenues into the genetic basis and evolution of chemical signaling in social insects.

ecology↗

bioRxiv2023

Genomic architecture of nestmate recognition cues in the desert ant

Nestmate recognition is the basis for cooperation within social insect colonies. Quantitative variation in cuticle hydrocarbons (CHCs) is used for nestmate recognition in ants and other social insects. We carried out a Genome Wide Association Study (GWAS) of CHCs in the desert ant Cataglyphis niger by sampling 47 colonies, fully sequencing six workers from each colony, and measuring the relative amounts of their CHCs. Under the Gestalt colony odour model, social interactions between nestmates, in which CHCs are being transferred and mixed, are essential in creating a uniform colony CHC profile. Therefore, we carried out a second GWAS between the colonies and their uniform Gestalt odour by averaging nestmate genotypes and comparing them to their averaged CHC amounts. Our results are in line with the Gestalt model. Together, the two analyses identified 99 candidate QTLs associated with 18 of the CHCs. Thirteen clusters of two to four QTLs located within 10cM from each other were identified, seven of which contained QTLs from both analyses. We conclude that nestmate recognition cues are a complex quantitative colony-level trait with a significant genetic component to their phenotypic variation and a highly polygenic architecture.

ecology↗

bioRxiv2020

ATP-Citrate lyase fuels axonal transport across species

Microtubule (MT)-based transport is an evolutionary conserved processed finely tuned by posttranslational modifications. Among them, α-tubulin acetylation, which is catalyzed by the α-tubulin N-acetyltransferase 1, Atat1, promotes the recruitment and processivity of molecular motors along MT tracks. However, the mechanisms that controls Atat1 activity remains poorly understood. Here, we show that a pool of vesicular ATP-citrate lyase Acly acts as a rate limiting enzyme to modulate Atat1 activity by controlling availability of Acetyl-Coenzyme-A (Acetyl-CoA). In addition, we showed that Acly expression is reduced upon loss of Elongator activity, further connecting Elongator to Atat1 in the pathway regulating α-tubulin acetylation and MT-dependent transport in projection neurons, across species. Remarkably, comparable defects occur in fibroblasts from Familial Dysautonomia (FD) patients bearing an autosomal recessive mutation in the gene coding for the Elongator subunit ELP1. Our data may thus shine new light on the pathophysiological mechanisms underlying FD.Competing Interest StatementThe authors have declared no competing interest.View Full Text

cell biology↗

bioRxiv2019

Differences in Long-Chained Cuticular Hydrocarbons between Males and Gynes in Cataglyphis Desert Ants

Cuticualar hydrocarbons play an important role in chemical communication in social insects, serving, among other things, as nestmate, gender, dominance and fertility recognition cues. In ants, however, very little is known about the precopulatory signals cuticular hydrocarbons carry. These signals may serve as affecting sex pheromones and aphrodisiacs or as reliable signals for idiosyncratic traits, which indirectly affect sexual selection. In this study, we examined, for the first time, in the Cataglyphis genus, sex-specific variability in cuticular hydrocarbons. We focused on a species that exhibits split sex-ratio and found significant quantitative differences between virgin queens and their potential mates. In an analyses of both absolute amounts and relative amounts, we found different compounds to be significantly displayed on gynes and drones, suggesting absolute and relative amounts may carry different signals influencing mating behavior and mate choice. We discuss the possible signals advertised by the non-polar fraction of these hydrocarbon profiles.

ecology↗

bioRxiv2018

Incipient species or social polymorphism? Diversity in the desert ant Cataglyphis

Species are the fundamental units upon which evolutionary research is based. In insects, due to the high level of hybridization, the delimitation of such species can be challenging. The genus Cataglyphis presents a high level of diversification, making it an excellent model with which to study evolutionary paths. Israel appears to be a \"hot spot\" for recent speciation in this genus. Although previous studies have described multiple species of Cataglyphis in Israel, a recent genetic study has questioned the existence of some of these historically described species. The present study focuses on an apparent species complex that is distinguishable by its mitochondrial DNA (and therefore named mitotypes) but not by its nuclear DNA. Using a multi-method approach (genetics, chemistry and behavior), we show that these mitotypes also differ in their social structures and are readily distinguishable by their cuticular hydrocarbons profiles. While the different mitotypes are in general allopatric, at our study site they all coexist but nonetheless maintain the observed differences between them. This raises many evolutionary questions: Are these incipient species that have diverged with gene flow, or is this a case of social and chemical polymorphism that is maintained within a single species.

evolutionary biology↗

bioRxiv2018

Comparative study of population genomic approaches for mapping colony-level traits

Social insect colonies exhibit colony-level phenotypes such as social immunity and task coordination, which are the sum of individual phenotypes. Mapping the genetic basis of such phenotypes requires associating the colony-level phenotype with the genotypes in the colony. In this paper, we examine alternative approaches to DNA extraction, library construction and sequencing for genome wide association (GWAS) studies of colony-level traits. We evaluate the accuracy of allele frequency estimation in sequencing a pool of individuals (pool-seq) from each colony in either whole-genome sequencing or reduced representation genomic sequencing. Based on empirical measurement of the experimental noise in sequencing DNA pools, we show that whole-genome pool-seq is more accurate than reduced representation pool-seq. We evaluate the power of the alternative approaches for detecting quantitative trait loci (QTL) of colony-level traits by using simulations that account for an environmental effect on the phenotype. Our results can inform experimental designs and enable optimizing the power of GWAS depending on budget, availability of samples and research goals. We conclude that for a given budget, sequencing un-normalized pools of individuals from each colony achieves greater QTL detection power.

bioinformatics↗

bioRxiv2018

Split sex-ratio and variability in aggressive behavior in the ant Cataglyphis niger

In social insects, non-nestmates interactions are typically agonistic and many factors may influence the degree of exhibited aggression. Two of these factors are the physical proximity between nests and the chemical dissimilarity between colonies chemical signatures. We studied a population sample of 43 colonies of Cataglyphis niger ants distributed along a transect of [~]4KM. This geographic distribution allowed us to examine correlations of aggression levels with physical and chemical distances. Ants were collected before mating season, when sexuals (unmated gynes and drones) could be found in nests. In our sample, colonies had either gynes or drones but never both. The presence of sexuals, therefore, was another factor we took into account in our behavioral analyses. Workers from nests with sexuals were more aggressive towards conspecifics than workers from nests where sexuals were absent. We also found those workers to be more vigorously active towards colonies with greater chemical distances, while workers from nests without sexuals were indifferent to chemical distances. We therefore concluded that ants are able to detect differences in chemical dissimilarity, but their aggression levels are mainly determined by other mechanisms. A possible additional mechanism is associative learning and long term memory of the chemical signatures of neighboring colonies. Such learning is supported by our finding that aggression is higher towards neighboring nests, which is in line with the previously reported nasty neighbour effect in Cataglyphis ants. These results suggest that previous experience and learning of neural templates representing neighbors chemical cues is a stronger component than chemical dissimilarity in the mechanisms which determine aggression towards conspecifics in this species. We discuss possible explanations for the observed effect of the presence of sexuals on agonistic behavior and responsiveness to chemical distances.

evolutionary biology↗