You Snooze, You Lose: Sleep serves restorative and memory functions, but it does not always operate analogously across species. Deferral of sleep may be possible when selection strongly favors the awake. Lesku et al. (p. 1654 ; see the Perspective by Siegel ) show that sleep may be deferred without cost or impairment in pectoral sandpipers. These birds breed collectively in the high Arctic, and male competition is intense. Competing for, and displaying to, females are both physically and cognitively demanding, yet birds who slept the least showed no decrease in their ability to perform these activities. Indeed, those males who slept the least obtained the most matings and sired the most offspring.

Understanding the causes and consequences of variation in the rate of recombination is essential since this parameter is considered to affect levels of genetic variability, the efficacy of selection, and the design of association and linkage mapping studies. However, there is limited knowledge about the factors governing recombination rate variation. We genotyped 1920 single nucleotide polymorphisms in a multigeneration pedigree of more than 1000 zebra finches (Taeniopygia guttata) to develop a genetic linkage map, and then we used these map data together with the recently available draft genome sequence of the zebra finch to estimate recombination rates in 1 Mb intervals across the genome. The average zebra finch recombination rate (1.5 cM/Mb) is higher than in humans, but significantly lower than in chicken. The local rates of recombination in chicken and zebra finch were only weakly correlated, demonstrating evolutionary turnover of the recombination landscape in birds. The distribution of recombination events was heavily biased toward ends of chromosomes, with a stronger telomere effect than so far seen in any organism. In fact, the recombination rate was as low as 0.1 cM/Mb in intervals up to 100 Mb long in the middle of the larger chromosomes. We found a positive correlation between recombination rate and GC content, as well as GC-rich sequence motifs. Levels of linkage disequilibrium (LD) were significantly higher in regions of low recombination, showing that heterogeneity in recombination rates have left a footprint on the genomic landscape of LD in zebra finch populations.