We show that the diverse ecoregions of Madagascar share one distinctive climatic feature: unpredictable intra-or interannual precipitation compared with other regions with comparable rainfall. Climatic unpredictability is associated with unpredictable patterns of fruiting and flowering. It is argued that these features have shaped the evolution of distinctive characteristics in the mammalian fauna of the island. Endemic Herpestidae and Tenrecidae and members of five endemic primate families differ from closely related species elsewhere, exhibiting extremes of ''fastness'' and ''slowness'' in their life histories. Climatic features may also account for the dearth of frugivorous birds and mammals in Madagascar, and for the evolutionary prevalence of species with large body mass.climate ͉ life history ͉ unpredictability ͉ mammals R ecent field research on Madagascar has revealed related vertebrates with both the fastest and slowest life histories. How can such differences evolve under similar environmental conditions? The unique natural communities of Madagascar are famous, but efforts to explain their evolution are unsatisfactory. We show here that the climates of Madagascar are distinctive, with highly unpredictable rainfall, and argue that some of the natural communities of the island represent evolutionary responses to this unusually variable climatic regime.The communities of Madagascar are characterized by high levels of endemicity, great species diversity in some taxonomic groups, and a complete absence of others. These three features are dramatically evident in the native nonflying mammals. The four orders native to and widespread within Madagascar (Carnivora, Insectivora, Primata, and Rodentia) are all represented by endemic genera or families. The only other Recent mammals are the African bush pig (Potamochoerus larvatus), the extinct pygmy hippopotamus species (Hippopotamus spp.), and the poorly known and extinct Plesiorycteropus. Groups widely distributed elsewhere, such as the canids, felids, cervids, bovids, and anthropoid primates, are absent. Successful colonization by mammals has been rare (1). The high level of endemicity has been attributed to the long isolation of the island from other continents. This isolation predates the evolution of most recent families of mammals, and the limited suite of Malagasy mammals has been attributed to chance dispersals across the Mozambique Canal over the past 70 million years (1, 2).The Malagasy fauna exhibit other distinctive features not readily explained by isolation. For example, the biological peculiarities of the primates of Madagascar have been widely noted (3). The extreme seasonality and unpredictability and frequent tropical cyclones of Madagascar have been invoked to explain these peculiarities and relate them to a special need to conserve energy (3, 4). However, Madagascar does not exhibit an unusual degree of seasonality (5), and, lacking comparative evidence until now, there has been no assessment of the unpredictability of the climate of Madagasca...

Barcode swapping results in the mislabelling of sequencing reads between multiplexed samples on patterned flow-cell Illumina sequencing machines. This may compromise the validity of numerous genomic assays; however, the severity and consequences of barcode swapping remain poorly understood. We have used two statistical approaches to robustly quantify the fraction of swapped reads in two plate-based single-cell RNA-sequencing datasets. We found that approximately 2.5% of reads were mislabelled between samples on the HiSeq 4000, which is lower than previous reports. We observed no correlation between the swapped fraction of reads and the concentration of free barcode across plates. Furthermore, we have demonstrated that barcode swapping may generate complex but artefactual cell libraries in droplet-based single-cell RNA-sequencing studies. To eliminate these artefacts, we have developed an algorithm to exclude individual molecules that have swapped between samples in 10x Genomics experiments, allowing the continued use of cutting-edge sequencing machines for these assays.

A 16-year study of wild, unprovisioned sifaka Propithecus verreauxi verreauxi at Beza Mahafaly in southwest Madagascar provides estimates of age-speci®c fertility, mortality, and dispersal in a population of 426 marked animals, and longitudinal records of individual life histories. Sifaka females give birth for the ®rst time later and live longer, for their size, than mammals in other orders; they also give birth later and continue reproducing longer, for their size, than other primates. Theory postulates that these features, commonly referred to as bet-hedging, evolve in unpredictable environments in association with widely varying infant survival and a trade-off between reproductive effort and adult survival. The climate of south-west Madagascar is highly unpredictable compared to almost all other regions in the tropics with similar average rainfall, and we argue that sifaka females are bet-hedgers par excellence. Male sifaka, in contrast, become reproductively active at an earlier age than females, and are less likely to have long lives than females. The atypical direction of this asymmetry between males and females re¯ects a`slowing down' of female life histories rather than a`speeding up' of male life histories. Two other unusual features of sifaka biology and behaviour may be linked to the unpredictability of Madagascar's climate: intense local competition between females, and a sex ratio at birth strongly biased in favour of males in most years. In drought years, reproductive females must cope with suddenly intensi®ed resource constraints. This, in turn, may strongly limit the number of`breeding slots' available over the long-term for females.

When comparing biological conditions using mass cytometry data, one key challenge is to identify cellular populations that change in abundance. Here, we present a novel computational strategy for detecting these “differentially abundant” populations, by assigning cells to hyperspheres, testing for significant differences between conditions and controlling the spatial false discovery rate. The method’s performance is established using simulations and real data where it finds novel patterns of differential abundance.