Introduction: Politics, Geographies and Histories in Workers’ Education

Tamboukou, M., Introduction: Politics, Geographies and Histories in Workers’ Education, 2016, reproduced with permission of Palgrave Macmillan. This extract is taken from the author's original manuscript and has not been edited. The definitive, published, version of record is available here: http://www.palgrave.com/gb/book/9781137490148#aboutBoo

Whole-chromosome hitchhiking driven by a male-killing endosymbiont

Neo-sex chromosomes are found in many taxa, but the forces driving their emergence and spread are poorly understood. The female-specific neo-W chromosome of the African monarch (or queen) butterfly Danaus chrysippus presents an intriguing case study because it is restricted to a single ‘contact zone’ population, involves a putative colour patterning supergene, and co-occurs with infection by the the male-killing endosymbiont Spiroplasma. We investigated the origin and evolution of this system using whole genome sequencing. We first identify the ‘BC supergene’, a broad region of suppressed recombination across nearly half a chromosome, which links two colour patterning loci. Association analysis suggests that the genes yellow and arrow in this region control the forewing colour pattern differences between D. chrysippus subspecies. We then show that the same chromosome has recently formed a neo-W that has spread through the contact zone within ~2200 years. We also assembled the genome of the male-killing Spiroplasma, and find that it shows perfect genealogical congruence with the neo-W, suggesting that the neo-W has hitchhiked to high frequency as the male killer has spread through the population. The complete absence of female crossing-over in the Lepidoptera causes whole-chromosome hitchhiking of a single neo-W haplotype, carrying a single allele of the BC supergene, and dragging multiple non-synonymous mutations to high frequency. This has created a population of infected females that all carry the same recessive colour patterning allele, making the phenotypes of each successive generation highly dependent on uninfected male immigrants. Our findings show how hitchhiking can occur between the unlinked genomes of host and endosymbiont, with dramatic consequences.Martin, Simon et al. (2020), Data from: Whole-chromosome hitchhiking driven by a male-killing endosymbiont, v5, Dryad, Dataset, https://doi.org/10.5061/dryad.9kd51c5d

Total factor productivity growth on Britain's railways, 1852-1912: A reappraisal of the evidence

This paper revisits the issue of the productivity performance of Britain's railways with an improved dataset and modern cliometrics. We find a slowdown in TFP growth between 1850 and 1870, after which it stabilized at about 1.1%. An analysis of company-level productivity performance reveals large discrepancies in TFP growth and substantial cost inefficiency. The evidence suggests that there was managerial failure in companies with agency problems in a context of collusion and high entry barriers. A wider implication is that the neoclassical exoneration of late-Victorian British management may be less convincing for the services sector than for manufacturing