Robert Unckless

Robert Unckless
University of Kansas | KU · Department of Molecular Biosciences

PhD

About

173
Publications
8,331
Reads
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2,389
Citations
Citations since 2016
57 Research Items
1889 Citations
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20162017201820192020202120220100200300
20162017201820192020202120220100200300
20162017201820192020202120220100200300
Additional affiliations
August 2011 - July 2016
Cornell University
Position
  • PostDoc Position
July 2006 - August 2011
University of Rochester
Position
  • PhD Student

Publications

Publications (173)
Preprint
Full-text available
The genetic causes of phenotypic variation often differ depending on the population examined, particularly if the populations were founded by relatively small numbers of genotypes. Similarly, the genetic causes of phenotypic variation among similar traits (resistance to different xenobiotic compounds or pathogens) may also be completely different o...
Article
Full-text available
Meiotic drivers are selfish genetic elements that tinker with gametogenesis to bias their own transmission into the next generation of offspring. Such tinkering can have significant consequences on gametogenesis and end up hampering the spread of the driver. In Drosophila affinis, sex‐ratio meiotic drive is caused by an X‐linked complex that, when...
Preprint
Full-text available
CAREER grant 2047052 to RLU. Meiotic drivers are selfish genetic elements that tinker with gametogenesis to bias their own transmission into the next generation of offspring. Such tinkering can have significant consequences on gametogenesis and end up hampering the spread of the driver. In Drosophila affinis, sex-ratio meiotic drive is caused by an...
Article
Full-text available
Migration of neuroblasts and neurons from their birthplace is central to the formation of neural circuits and networks. ETR-1 is the Caenorhabditis elegans homolog of the CELF1 (CUGBP, ELAV-like family 1) RNA-processing factor involved in neuromuscular disorders. etr-1 regulates body wall muscle differentiation. Our previous work showed that etr-1...
Article
Full-text available
Wolbachia are a genus of widespread bacterial endosymbionts in which some strains can hijack or manipulate arthropod host reproduction. Male killing is one such manipulation in which these maternally transmitted bacteria benefit surviving daughters in part by removing competition with the sons for scarce resources. Despite previous findings of inte...
Article
Full-text available
Proteins involved in post-copulatory interactions between males and females are among the fastest evolving genes in many species, usually attributed to their involvement in reproductive conflict. As a result, these proteins are thought to often be in the formation of postmating-prezygotic incompatibilities between species. The Drosophila dunni subg...
Preprint
Full-text available
Wolbachia are widespread bacterial endosymbionts that infect a large proportion of insect species. While some strains of this bacteria do not cause observable host phenotypes, many strains of Wolbachia have some striking effects on their hosts. In some cases, these symbionts manipulate host reproduction to increase the fitness of infected, transmit...
Article
Over time, populations of species can expand, contract, fragment and become isolated, creating subpopulations that must adapt to local conditions. Understanding how species maintain variation after divergence as well as adapt to these changes in the face of gene flow is of great interest, especially as the current climate crisis has caused range sh...
Article
Full-text available
Hosts and viruses are constantly evolving in response to each other: as a host attempts to suppress a virus, the virus attempts to evade and suppress the host’s immune system. Here, we describe the recurrent evolution of a virulent strain of a DNA virus, which infects multiple Drosophila species. Specifically, we identified two distinct viral types...
Article
Full-text available
Scientists are rapidly developing synthetic gene drive elements intended for release into natural populations. These are intended to control or eradicate disease vectors and pests, or to spread useful traits through wild populations for disease control or conservation purposes. However, a crucial problem for gene drives is the evolution of resistan...
Article
Full-text available
Killer meiotic drivers are genetic parasites that destroy ‘sibling’ gametes lacking the driver allele. The fitness costs of drive can lead to selection of unlinked suppressors. This suppression could involve evolutionary tradeoffs that compromise gametogenesis and contribute to infertility. Schizosaccharomyces pombe, an organism containing numerous...
Article
Full-text available
Killer meiotic drivers are genetic parasites that destroy ‘sibling’ gametes lacking the driver allele. The fitness costs of drive can lead to selection of unlinked suppressors. This suppression could involve evolutionary tradeoffs that compromise gametogenesis and contribute to infertility. Schizosaccharomyces pombe, an organism containing numerous...
Preprint
Full-text available
Background: Proteins involved in post-copulatory interactions between males and females are among the fastest evolving genes in many species and this has been attributed to reproductive conflict. Likely as a result, these proteins are frequently involved in cases of post-mating-prezygotic isolation between species. The Drosophila dunni subgroup con...
Preprint
Full-text available
Killer meiotic drivers are genetic parasites that destroy 'sibling' gametes lacking the driver allele. The fitness costs of drive can lead to selection of unlinked suppressors. This suppression could involve evolutionary tradeoffs that compromise gametogenesis and contribute to infertility. Schizosaccharomyces pombe, an organism containing numerous...
Preprint
Drosophila melanogaster and Caenorhabditis elegans are well-used invertebrate models for studying the innate immune system. The organisms are susceptible to bacterial pathogens that include Pseudomonas species, (entomophilia – Drosophila) or (aeruginosa – Caenorhabditis), E. faecalis and P. rettgeri , which are or are related to human pathogens. Fu...
Article
Full-text available
Dissecting the genetic basis of natural variation in disease response in hosts provides insights into the coevolutionary dynamics of host-pathogen interactions. Here, a genome-wide association study of Drosophila melanogaster survival after infection with the Gram-positive entomopathogenic bacterium Enterococcus faecalis is reported. There was cons...
Article
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There is a developing interest in how immune genes may function in other physiological roles, and how traditionally non-immune peptides may, in fact, be active in immune contexts. In the absence of infection, the induction of the immune response is costly, and there are well-characterized trade-offs between immune defense and fitness. The agents be...
Article
Most organisms are constantly adapting to pathogens and parasites that exploit their host for their own benefit. Less studied, but perhaps more ubiquitous, are intragenomic parasites or selfish genetic elements. These include transposable elements, selfish B chromosomes and meiotic drivers that promote their own replication without regard to fitnes...
Article
Full-text available
Wolbachia are the most widespread maternally-transmitted bacteria in the animal kingdom. Their global spread in arthropods and varied impacts on animal physiology, evolution, and vector control are in part due to parasitic drive systems that enhance the fitness of infected females, the transmitting sex of Wolbachia. Male killing is one common drive...
Article
Full-text available
Genes involved in immune defense against pathogens provide some of the most well-known examples of both directional and balancing selection. Antimicrobial peptides (AMPs) are innate immune effector genes, playing a key role in pathogen clearance in many species, including Drosophila. Conflicting lines of evidence have suggested AMPs may be under di...
Article
Full-text available
Copy number variants (CNV) are associated with phenotypic variation in several species. However, properly detecting changes in copy numbers of sequences remains a difficult problem, especially in lower quality or lower coverage next-generation sequencing data. Here, inspired by recent applications of machine learning in genomics, we describe a meth...
Article
Full-text available
Pathogenic microbes can exert extraordinary evolutionary pressure on their hosts. They can spread rapidly and sicken or even kill their host to promote their own proliferation. Because of this strong selective pressure, immune genes are some of the fastest evolving genes across metazoans, as highlighted in mammals and insects. Drosophila melanogast...
Preprint
Full-text available
Copy number variants (CNV) are associated with phenotypic variation in several species. However, properly detecting changes in copy numbers of sequences remains a difficult problem, especially in lower quality or lower coverage next-generation sequencing data. Here, inspired by recent applications of machine learning in genomics, we describe a meth...
Article
In sexual reproduction, opportunities are limited and the stakes are high. This inevitably leads to conflict. One pervasive conflict occurs within genomes between alternative alleles at heterozygous loci. Each gamete and thus each offspring will inherit only one of the two alleles from a heterozygous parent. Most alleles 'play fair' and have a 50%...
Article
Full-text available
It is common to find considerable genetic variation in susceptibility to infection in natural populations. We have investigated whether natural selection increases this variation by testing whether host populations show more genetic variation in susceptibility to pathogens that they naturally encounter than novel pathogens. In a large cross-infecti...
Preprint
Very little is known of the antibiotic resistance mechanisms of members of the Chromobacterium genus. In previous studies of Chromobacterium subtsugae (formerly C. violaceum ) strain CV017, we identified a resistance nodulation division (RND)-family efflux pump (CdeAB-OprM). Here, we show the cdeAB-oprM genes are widely distributed in members of th...
Preprint
Full-text available
It is common to find considerable genetic variation in susceptibility to infection in natural populations. We have investigated whether natural selection increases this variation by testing whether host populations show more genetic variation in susceptibility to pathogens that they naturally encounter than novel pathogens. In a large cross-infecti...
Article
Selfish genetic elements that manipulate gametogenesis to achieve a transmission advantage are known as meiotic drivers. Sex‐ratio X‐chromosomes (SR) are meiotic drivers that prevent the maturation of Y‐bearing sperm in male carriers to result in the production of mainly female progeny. The spread of an SR chromosome can affect host genetic diversi...
Preprint
Full-text available
Viruses make up a considerable proportion of the pathogens infecting animals. They can spread rapidly between hosts, and sicken or even kill their hosts to promote their own proliferation. Due to this strong selective pressure, antiviral immune genes are some of the fastest evolving genes across metazoans, as highlighted in mammals and insects. Whi...
Preprint
Genes involved in immune defense against pathogens provide some of the most well-known examples of both directional and balancing selection. Antimicrobial peptides (AMPs) are innate immune effector genes, playing a key role in pathogen clearance in many species, including Drosophila . Conflicting lines of evidence have suggested AMPs may be under d...
Article
Full-text available
Drosophila melanogaster is a model for the study of innate immunity, yet we have limited knowledge of its natural pathogens. In this study, we sequenced the genome ofLysinibacillus fusiformisstrain Juneja, isolated from laboratory fly stocks. As a Gram-positive bacterium with unique peptidoglycans, this strain may provide a new model for pathogen r...
Article
Viruses coevolve with their hosts to overcome host resistance and gain the upper hand in the evolutionary arms race. Drosophila innubila nudivirus (DiNV) is a double stranded DNA virus, closely related to Oryctes rhinoceros nudivirus (OrNV) and Kallithea virus. DiNV is the first DNA virus found to naturally infect Drosophila and therefore has the p...
Article
Full-text available
Hosts and viruses are locked in an evolutionary arms race. Hosts are constantly evolving to suppress virulence and replication, while viruses, which are reliant on host machinery for survival and reproduction, develop counterstrategies to escape this immune defense. Viruses must also adapt to novel conditions while establishing themselves in a host...
Article
Full-text available
Postcopulatory sexual selection (PCSS) is a potent evolutionary force that can drive rapid changes of reproductive genes within species, and thus has the potential to generate reproductive incompatibilities between species. Male seminal fluid proteins (SFPs) are major players in postmating interactions, and are important targets of PCSS in males. T...
Preprint
Full-text available
Postcopulatory sexual selection (PCSS) is a potent evolutionary force that can drive rapid changes of reproductive genes within species, and thus has the potential to generate reproductive incompatibilities between species. Male seminal fluid proteins (SFPs) are major players in postmating interactions, and likely the main targets of PCSS in males....
Article
Full-text available
Drosophila melanogaster is able to thrive in harsh northern climates through adaptations in life-history traits and physiological mechanisms that allow for survival through the winter. We examined the genetic basis of natural variation in one such trait, female virgin egg retention, which was previously shown to vary clinally and seasonally. To fur...
Article
CRISPR/Cas9 gene drive (CGD) promises a highly adaptable approach for spreading genetically engineered alleles throughout a species, even if those alleles impair reproductive success. CGD has been shown to be effective in laboratory crosses of insects, yet it remains unclear to what extent potential resistance mechanisms will affect the dynamics of...
Preprint
Full-text available
The idea of driving genetically modified alleles to fixation in a population has fascinated scientists for over 40 years 1,2 . Potential applications are broad and ambitious, including the eradication of disease vectors, the control of pest species, and the preservation of endangered species from extinction ³ . Until recently, these possibilities h...
Article
Full-text available
Genes involved in immune defence are among the fastest evolving in the genomes of many species. Interestingly, however, genes encoding antimicrobial peptides (AMPs) have shown little evidence for adaptive divergence in arthropods, despite the centrality of these peptides in direct killing of microbial pathogens. This observation, coupled with a fai...
Article
Meiotic drivers are genetic variants that selfishly manipulate the production of gametes to increase their own rate of transmission, often to the detriment of the rest of the genome and the individual that carries them. This genomic conflict potentially occurs whenever a diploid organism produces a haploid stage, and can have profound evolutionary...
Article
Genes of the immune system often evolve rapidly and adaptively, presumably driven by antagonistic interactions with pathogens [1-4]. Those genes encoding secreted antimicrobial peptides (AMPs), however, have failed to exhibit conventional signatures of strong adaptive evolution, especially in arthropods (e.g., [5, 6]) and often segregate for null a...
Article
Full-text available
The use of recombinant genetic technologies for population manipulation has mostly remained an abstract idea due to the lack of a suitable means to drive novel gene constructs to high frequency in populations. Recently Gantz and Bier showed that the use of CRISPR/Cas9 technology could provide an artificial drive mechanism, the so-called Mutagenic C...
Article
Full-text available
Both malnutrition and undernutrition can lead to compromised immune defense in a diversity of animals, and "nutritional immunology" has been suggested as a means of understanding immunity and determining strategies for fighting infection. The genetic basis for the effects of diet on immunity, however, has been largely unknown. In the present study,...
Article
Full-text available
Individuals are genetically variable for both the way in which they processes nutrients and in the effects of dietary content on reproductive success, immunity and development. Here we survey genetic variation for nutrients stores (glucose, glycogen, glycerol, protein, triglycerides and wet weight) in the Drosophila Genetic Reference Panel (DGRP) a...
Article
Full-text available
Genetic elements that cheat Mendelian segregation by biasing transmission in their favor gain a significant fitness benefit. Several examples of sex-ratio meiotic drive, where one sex chromosome biases its own transmission at the cost of the opposite sex chromosome, exist in animals and plants. While the distorting sex chromosome gains a significan...
Article
Full-text available
Evolutionary rescue occurs when a population that is threatened with extinction by an environmental change adapts to the change sufficiently rapidly to survive. Here we extend the mathematical theory of evolutionary rescue. In particular, we model evolutionary rescue to a sudden environmental change when adaptation involves evolution at a single lo...
Article
It has long been known that processes occurring within a species may impact the interactions between species. For example, as competitive ability is sensitive to parameters including reproductive rate, carrying capacity and competition efficiency, the outcome of interspecific competition may be influenced by any process that alters these attributes...
Article
Many maternally inherited endosymbionts manipulate their host's reproduction in various ways to enhance their own fitness. One such mechanism is male killing (MK), in which sons of infected mothers are killed by the endosymbiont during development. Several hypotheses have been proposed to explain the advantages of MK, including resource reallocatio...
Data
Sequences for short DiNV orthologs of other Nudiviruses. Note these are too short (<200bp) to be published in Genbank. (DOC)
Data
Full-text available
The phylogenetic relationships of DiNV isolated from Drosophila species collected near Portal, AZ (blue) and Rochester, NY (red). Branch labels are posterior probability/maximum likelihood bootstrap support. (PDF)
Data
Schematic of viral nucleic acid enrichment protocol. Note there is no DNA digestion during the RNA extraction. (EPS)
Data
Distribution of BLAST hits corresponding to Drosophila C virus according to position in the genome. (PNG)
Article
Full-text available
Little is known about the viruses infecting most species. Even in groups as well-studied as Drosophila, only a handful of viruses have been well-characterized. A viral metagenomic approach was used to explore viral diversity in 83 wild-caught Drosophila innubila, a mushroom feeding member of the quinaria group. A single fly that was injected with,...
Article
Endosymbionts infect most arthropods and cause a wide variety of phenotypes in their hosts, ranging from obligate mutualists to reproductive parasites. One of the most dramatic forms of reproductive parasitism is male-killing which involves the endosymbiont killing all of the sons of infected females. A phenotype with such a dramatic effect on host...