The policy response to Coronavirus : theory and application

In order to guard against and mitigate the potential economic impacts of the pandemic, different policies have been implemented by the UK government and the Bank of England. In this report we aim to look at the rationale behind the implementation of both fiscal and monetary policies and what the potential consequences would have been in their absence. We look at three main levers: conventional monetary policy, unconventional monetary policy and fiscal policy. For each we review the theory before setting this into context. There have been constraints on policymakers’ ability to implement some of these levers due to the macroeconomic situation prior to the pandemic, particularly with respect to conventional monetary policy where interest rates were already close to their effective lower bound. Unconventional monetary policy has continued in the form of quantitative easing, with some new tools being used during this pandemic and hints that so far unused methods, such as negative interest rates, are being considered. Fiscal policy has been where the most inventive and far-reaching policies have been found, with extremely high expenditure permitted by very low borrowing rates faced by government, partly itself enabled by the supportive actions of the Bank of England. This article describes some of the key policy changes that we have seen over the past year and attempts to provide a good basis to understand the rationale for the policy choices, underpinned by economic theory. This article does not gauge success (or otherwise) of specific policies but is intended as a record of events with explanations of the reasoning behind them

Faster-X effects in two Drosophila lineages

Under certain circumstances, X-linked loci are expected to experience more adaptive substitutions than similar autosomal loci. To look for evidence of faster-X evolution, we analyzed the evolutionary rates of coding sequences in two sets of Drosophila species, the melanogaster and pseudoobscura clades, using whole-genome sequences. One of these, the pseudoobscura clade, contains a centric fusion between the ancestral X chromosome and the autosomal arm homologous to 3L in D. melanogaster. This offers an opportunity to study the same loci in both an X-linked and an autosomal context, and to compare these loci with those that are only X-linked or only autosomal. We therefore investigated these clades for evidence of faster-X evolution with respect to nonsynonymous substitutions, finding mixed results. Overall, there was consistent evidence for a faster-X effect in the melanogaster clade, but not in the pseudoobscura clade, except for the comparison between D. pseudoobscura and its close relative, Drosophila persimilis. An analysis of polymorphism data on a set of genes from D. pseudoobscura that evolve rapidly with respect to their protein sequences revealed no evidence for a faster-X effect with respect to adaptive protein sequence evolution; their rapid evolution is instead largely attributable to lower selective constraints. Faster-X evolution in the melanogaster clade was not related to male-biased gene expression; surprisingly, however, female-biased genes showed evidence for faster-X effects, perhaps due to their sexually antagonistic effects in males