Catálogo de publicaciones - revistas

<jats:p>The rate of adaptive evolution, the contribution of selection to genetic changes that increase mean fitness, is determined by the additive genetic variance in individual relative fitness. To date, there are few robust estimates of this parameter for natural populations, and it is therefore unclear whether adaptive evolution can play a meaningful role in short-term population dynamics. We developed and applied quantitative genetic methods to long-term datasets from 19 wild bird and mammal populations and found that, while estimates vary between populations, additive genetic variance in relative fitness is often substantial and, on average, twice that of previous estimates. We show that these rates of contemporary adaptive evolution can affect population dynamics and hence that natural selection has the potential to partly mitigate effects of current environmental change.</jats:p>

<jats:p>Single-cell genomics studies have decoded the immune cell composition of several human prenatal organs but were limited in describing the developing immune system as a distributed network across tissues. We profiled nine prenatal tissues combining single-cell RNA sequencing, antigen-receptor sequencing, and spatial transcriptomics to reconstruct the developing human immune system. This revealed the late acquisition of immune-effector functions by myeloid and lymphoid cell subsets and the maturation of monocytes and T cells before peripheral tissue seeding. Moreover, we uncovered system-wide blood and immune cell development beyond primary hematopoietic organs, characterized human prenatal B1 cells, and shed light on the origin of unconventional T cells. Our atlas provides both valuable data resources and biological insights that will facilitate cell engineering, regenerative medicine, and disease understanding.</jats:p>

<jats:p> Characterizing complex microbial communities with single-cell resolution has been a long-standing goal of microbiology. We present Microbe-seq, a high-throughput method that yields the genomes of individual microbes from complex microbial communities. We encapsulate individual microbes in droplets with microfluidics and liberate their DNA, which we then amplify, tag with droplet-specific barcodes, and sequence. We explore the human gut microbiome, sequencing more than 20,000 microbial single-amplified genomes (SAGs) from a single human donor and coassembling genomes of almost 100 bacterial species, including several with multiple subspecies strains. We use these genomes to probe microbial interactions, reconstructing the horizontal gene transfer (HGT) network and observing HGT between 92 species pairs; we also identify a significant in vivo host-phage association between crAssphage and one strain of <jats:italic>Bacteroides vulgatus</jats:italic> . Microbe-seq contributes high-throughput culture-free capabilities to investigate genomic blueprints of complex microbial communities with single-microbe resolution. </jats:p>

<jats:p>Memristive devices, which combine a resistor with memory functions such that voltage pulses can change their resistance (and hence their memory state) in a nonvolatile manner, are beginning to be implemented in integrated circuits for memory applications. However, memristive devices could have applications in many other technologies, such as non–von Neumann in-memory computing in crossbar arrays, random number generation for data security, and radio-frequency switches for mobile communications. Progress toward the integration of memristive devices in commercial solid-state electronic circuits and other potential applications will depend on performance and reliability challenges that still need to be addressed, as described here.</jats:p>

<jats:p> The long neck of the giraffe has been held as a classic example of adaptive evolution since Darwin’s time. Here we report on an unusual fossil giraffoid, <jats:italic>Discokeryx xiezhi</jats:italic> , from the early Miocene, which has an unusual disk-shaped headgear and the most complicated head-neck joints in known mammals. The distinctive morphology and our finite element analyses indicate an adaptation for fierce head-butting behavior. Tooth enamel isotope data suggest that <jats:italic>D. xiezhi</jats:italic> occupied a niche different from that of other herbivores, comparable to the characteristic high-level browsing niche of modern giraffes. The study shows that giraffoids exhibit a higher headgear diversity than other ruminants and that living in specific ecological niches may have fostered various intraspecific combat behaviors that resulted in extreme head-neck morphologies in different giraffoid lineages. </jats:p>

<jats:p>There is no such thing as “zero-COVID.” As the Omicron variant spreads to China’s capital city, Beijing, the question is not if, but when and how, China will begin to “live with COVID-19” rather than continue to impose endless lockdowns. The problem is that under China’s stifling political climate, this notion cannot be uttered, let alone debated. How did a country with a history of deep respect for science and a laser focus on becoming a global powerhouse in technology and innovation fall into such isolation from the rest of the world?</jats:p>

<jats:p>America is reeling from yet another devastating spate of mass shootings. Last month, in the span of 10 days, shooters targeted a Taiwanese church in California, a grocery store in a Black neighborhood in New York, and an elementary school in Texas. Although opponents of sensible gun control—the kind that prevails throughout most of the civilized world—continue to put the spotlight on the shooters’ motivations or unstable mental states, these are cynical diversions from the one obvious truth: The common thread in all of the country’s revolting mass shootings is the absurdly easy access to guns. The science is clear: Restrictions work, and it’s likely that even more limitations would save thousands of lives. So why not take the laws much further, as other countries have done? The alternative is painfully obvious—living with more and more senseless carnage, courtesy of the National Rifle Association and their well-funded political lackeys.</jats:p>

<jats:p>Triple whammy of pandemic lockdowns, supply chain issues, and inflation hits many</jats:p>