Big Data, Small Media

A review ofAndrew DubberRadio in the Digital AgePolity, Cambridge, 2013 Charles EssDigital Media Ethics, Second EditionPolity, Cambridge, 2014 Graeme KirkpatrickComputer Games and the Social ImaginaryPolity, Cambridge, 2013 Dhiraj MurthyTwitter: Social Communication in the Twitter AgePolity, Cambrige, 2013 Jill Walker RettbergBlogging, Second EditionPolity, Cambridge, 201

Population Genetics of Island Endemics: Neutral and Major Histocompatibility Loci

Island archipelagoes are ideal for the study of microevolutionary forces due to their multiple, closely related but geographically disjunct populations. I used both neutral and major histocompatibility complex (MHC) loci to determine the population genetic structures of bird species endemic to the Galapagos Islands. MHC molecules recognize foreign pathogens in the body, and these loci are known for their high degree of genetic variability maintained by natural selection. Small island populations are predicted to have reduced genetic variability due to the effects of genetic drift; however, selection may be strong enough to prevent the loss of variability at MHC loci. First, I characterized neutral genetic structure in the Galapagos hawk (Buteo galapagoensis). Analyses of both neutral nuclear VNTR (Chapter 1) and mitochondrial (Chapter 2) loci showed low within-population variability but high between-population differentiation. In Chapter 3, we found that smaller, more inbred populations had birds with higher louse loads and, in general, lower and less variable natural antibody titres than the larger, more genetically variable hawk populations. Chapter 4 presents MHC work done on the Galapagos penguin (Spheniscus mendiculus), a seabird whose breeding colonies experience population bottlenecks associated with El Niqo events. Galapagos penguins had low variability, having only three MHC alleles which differed by only a few base pairs. MHC work on the Galapagos hawks (Chapter 5) revealed similarly low variability. Galapagos hawks had fewer and less divergent alleles than the Swainson?s hawk, their closest mainland relative. The MHC diversity in both the Galapagos species was lower than in the mainland species, indicating that genetic drift has had an overwhelming effect. Lastly, in Chapter 6, I characterized the neutral population genetic structure of six Galapagos mockingbird (Mimus spp.) populations. Genetic variability increased with island area and we found a pattern of isolation by distance, both indicating the influence of genetic drift. Significant levels of genetic and morphological differentiation existed among all six populations, though morphological distances were smaller between islands of similar area suggesting the influence of natural selection

‘Do You Really Want to Live Forever?’: Animism, Death, and the Trouble of Digital Images

This essay examines two works of video art to think through the apparent ‘immortality’ of recorded data and digital images, along with the use of ‘animism’ as a framework to describe the ‘liveliness’ of objects in recent cultural theory. In discussing Cécile B. Evans’ Hyperlinks or it Didn’t Happen (2014) and Korakrit Arunanondchai’s Painting with history in a room filled with people with funny names 3 (2016), we highlight how framings of death and digital images are not uniform, and are often articulated to other cultural beliefs. Yet these beliefs cannot be temporally or spatially opposed in any rigid fashion (as ‘modern’ or ‘premodern’, ‘Western’ or ‘Eastern’), in spite of attempts to suggest a ‘return’ to animism to theorise the agency of objects is an embrace of premodern, non-Western epistemologies and ontologies. The ‘troubled images’ we discuss here should be thought through a sense of ‘trouble’ derived from Donna Haraway: as stirring up, or making cloudy. We aim to further complicate and ‘trouble’ the ethical imperatives of animism (in the work of those like Haraway) given the role of digital media in sustaining or putting into practice the animisms of our present. In doing this, we also advance an ontological argument about data and its relationality, suggesting that data be theorised through tropes of metonymy and synecdoche

Disconnection Notices: Networks and Power at the Intersection of Technology, Biology, and Finance

This dissertation argues that the concept of the network has brought together technology, economics, biology, and the social under a feigned logic of totality. This study examines the origins and everyday implications of this totalizing network discourse. When networks are taken to describe all relations, the connections and flows of the above four areas define all that exists. But we are not connected thanks to the material structure of new technological and social networks. Instead, we have been made to think of ourselves as connected through the naturalization of an ideology. That which does not connect properly is rendered an aberration from existence. This dissertation is comprised of two parts. The first part argues that the academic theorization of networks emphasizes materiality and nature in such a way as to assume there are no alternatives to networks. Connectivity and flow inevitably ground all possibilities for our contemporary moment, if not all eternity. This reading of networks is ahistorical. When the history of network discourse is acknowledged, it is clear that our understanding of networks has cultural origins that are centuries old. Networks, connectivity, and flow are contingent assumptions about reality, naturalized through technology and discourse. The second part examines how the naturalization of network ideology produces subjects that are compelled to manage connectivity and flow throughout the network as a whole. Connection management does not stop at the individual. Managing the self is equated to the management of the network--and the management of the entire network is impossible. Thus, individual human beings are rendered insignificant or dangerous to the management of connection and flow. The two case studies discussed in this part, which examine various forms of social networks, together present how the empowerment produced through connectivity becomes disempowerment when individuals must manage both their own personal connections and flows along with the connectivity and flow of the networked totality

Drift, not selection, shapes toll-like receptor variation among oceanic island populations

Understanding the relative role of different evolutionary forces in shaping the level and distribution of functional genetic diversity among natural populations is a key issue in evolutionary and conservation biology. To do so accurately genetic data must be analyzed in conjunction with an unambiguous understanding of the historical processes that have acted upon the populations. Here we focused on diversity at toll-like receptor (TLR) loci, which play a key role in the vertebrate innate immune system and, therefore, are expected to be under pathogen-mediated selection. We assessed TLR variation within and among 13 island populations (grouped into three archipelagos) of Berthelot's pipit, Anthus berthelotii, for which detailed population history has previously been ascertained. We also compared the variation observed with that found in its widespread sister species, the tawny pipit, Anthus campestris. We found strong evidence for positive selection at specific codons in TLR1LA, TLR3 and TLR4. Despite this, we found that at the allele frequency level, demographic history has played the major role in shaping patterns of TLR variation in Berthelot's pipit. Levels of diversity and differentiation within and across archipelagos at all TLR loci corresponded very closely with neutral microsatellite variation, and with the severity of the bottlenecks that occurred during colonization. Our study shows that despite the importance of TLRs in combating pathogens, demography can be the main driver of immune gene variation within and across populations, resulting in patterns of functional variation that can persist over evolutionary timescales. This article is protected by copyright. All rights reserved

MHC class I loci of the Bar-Headed goose (Anser indicus)

MHC class I proteins mediate functions in anti-pathogen defense. MHC diversity has already been investigated by many studies in model avian species, but here we chose the bar-headed goose, a worldwide migrant bird, as a non-model avian species. Sequences from exons encoding the peptide-binding region (PBR) of MHC class I molecules were isolated from liver genomic DNA, to investigate variation in these genes. These are the first MHC class I partial sequences of the bar-headed goose to be reported. A preliminary analysis suggests the presence of at least four MHC class I genes, which share great similarity with those of the goose and duck. A phylogenetic analysis of bar-headed goose, goose and duck MHC class I sequences using the NJ method supports the idea that they all cluster within the anseriforms clade

High major histocompatibility complex class I polymorphism despite bottlenecks in wild and domesticated populations of the zebra finch ()

Background Two subspecies of zebra finch, Taeniopygia guttata castanotis and T. g. guttata are native to Australia and the Lesser Sunda Islands, respectively. The Australian subspecies has been domesticated and is now an important model system for research. Both the Lesser Sundan subspecies and domesticated Australian zebra finches have undergone population bottlenecks in their history, and previous analyses using neutral markers have reported reduced neutral genetic diversity in these populations. Here we characterize patterns of variation in the third exon of the highly variable major histocompatibility complex (MHC) class I α chain. As a benchmark for neutral divergence, we also report the first mitochondrial NADH dehydrogenase 2 (ND2) sequences in this important model system. Results Despite natural and human-mediated population bottlenecks, we find that high MHC class I polymorphism persists across all populations. As expected, we find higher levels of nucleotide diversity in the MHC locus relative to neutral loci, and strong evidence of positive selection acting on important residues forming the peptide-binding region (PBR). Clear population differentiation of MHC allele frequencies is also evident, and this may be due to adaptation to new habitats and associated pathogens and/or genetic drift. Whereas the MHC Class I locus shows broad haplotype sharing across populations, ND2 is the first locus surveyed to date to show reciprocal monophyly of the two subspecies. Conclusions Despite genetic bottlenecks and genetic drift, all surveyed zebra finch populations have maintained high MHC Class I diversity. The diversity at the MHC Class I locus in the Lesser Sundan subspecies contrasts sharply with the lack of diversity in previously examined neutral loci, and may thus be a result of selection acting to maintain polymorphism. Given uncertainty in historical population demography, however, it is difficult to rule out neutral processes in maintaining the observed diversity. The surveyed populations also differ in MHC Class I allele frequencies, and future studies are needed to assess whether these changes result in functional immune differences

Contrasting Epidemic Histories Reveal Pathogen-Mediated Balancing Selection on Class II MHC Diversity in a Wild Songbird

The extent to which pathogens maintain the extraordinary polymorphism at vertebrate Major Histocompatibility Complex (MHC) genes via balancing selection has intrigued evolutionary biologists for over half a century, but direct tests remain challenging. Here we examine whether a well-characterized epidemic of Mycoplasmal conjunctivitis resulted in balancing selection on class II MHC in a wild songbird host, the house finch (Carpodacus mexicanus). First, we confirmed the potential for pathogen-mediated balancing selection by experimentally demonstrating that house finches with intermediate to high multi-locus MHC diversity are more resistant to challenge with Mycoplasma gallisepticum. Second, we documented sequence and diversity-based signatures of pathogen-mediated balancing selection at class II MHC in exposed host populations that were absent in unexposed, control populations across an equivalent time period. Multi-locus MHC diversity significantly increased in exposed host populations following the epidemic despite initial compromised diversity levels from a recent introduction bottleneck in the exposed host range. We did not observe equivalent changes in allelic diversity or heterozygosity across eight neutral microsatellite loci, suggesting that the observations reflect selection rather than neutral demographic processes. Our results indicate that a virulent pathogen can exert sufficient balancing selection on class II MHC to rescue compromised levels of genetic variation for host resistance in a recently bottlenecked population. These results provide evidence for Haldane's long-standing hypothesis that pathogens directly contribute to the maintenance of the tremendous levels of genetic variation detected in natural populations of vertebrates