The University of Toronto Mississauga

Climate change may dramatically affect the animal species observed in North American cities, according to a new study. Climate change may dramatically affect the animal species observed in North American cities, according to a study published March 27 in the open-access journal PLOS ONE by Alessandro Filazzola of the University of Toronto Mississauga and Apex Resource Management Solutions, Canada, and colleagues. Urban dwellers bond with the biodiversity around them, from backyard birds to the mascots of local sports teams. But due to the effects of climate change, residents of US and Canadian cities may encounter a different cast of animal characters by 2100. Filazzola and colleagues studied the impact of human-caused climate change on more than 2,000 animal species historically found in the 60 most populous North American cities. First, the researchers used online species distribution databases generated by citizen science initiatives to download a record of terrestrial animal species sightings in each city. They acknowledge potential issues with the reliability of data which is largely generated from citizen science initiatives. The researchers then used machine learning to predict the most suitable conditions for each species, based on three differing emissions scenarios, by the end of the century. Results indicated a turnover of urban biodiversity by 2100 across almost all cities measured. Cities with high historic species richness were predicted to have the largest declines and fewest gains in species. Geographically, cooler, wetter cities (e.g. Omaha and Kansas City) may welcome the most new species, with Quebec, Ottawa, and Winnipeg nearly doubling their species roster. Warmer cities with higher precipitation (e.g. coastal California) may lose the most species. Arid southwestern cities like Phoenix and Albuquerque are not expected to experience a dramatic species shift, likely due to their resilient ecosystems. Fifty-four species may vanish entirely from the 60 tested cities. When examining changes by taxon, over 95% of bird and insect species were predicted to experience a change in the number of cities they occupy. Canines, most amphibians, and loons (aquatic birds) may experience the greatest losses in cities, while turtles, mice, toads and pelicans may become more common overall. The authors suggest that "an individual who lives a lifetime within the same city will likely observe changes in the species that occur around them." As this is a modelling study, these predictions need to be followed by ecological analyses. Further research can address how variables other than climate affect species distribution and explore how city living may bring additional stressors to animals. The researchers state that future projections are dependent on society's ability to curb greenhouse gas emissions, and they encourage future efforts to protect biodiversity. The authors add: "For people living in cities, the animals in their backyards and local green spaces are going to change significantly with climate change. Over the next few decades, familiar species will be leaving the city and new species will be entering it, forever changing the composition of urban animals."

Researchers have discovered new cell types in the visual system of flies, made possible by their creation of a tool that finds and labels neurons during development. The study combines single-cell sequencing data with a novel algorithm to identify pairs of genes that point to previously unknown cells in the brains of fruit flies. New York University researchers have discovered new cell types in the visual system of flies, made possible by their creation of a tool that finds and labels neurons during development. The study, published in the journal Proceedings of the National Academy of Sciences (PNAS), combines single-cell sequencing data with a novel algorithm to identify pairs of genes that point to previously unknown cells in the brains of fruit flies. Fruit flies (also known as Drosophila) have long been used as a model organism to study fundamental questions about the development and function of the brain. Instead of the 86 billion neurons found in humans, fruit flies have about 100,000 neurons -- making research into the brain a more manageable, yet still complex, endeavor. The use of genetic tools that can distinguish different types of cells in fruit flies has revolutionized the study of neural circuits in the brain, allowing scientists to understand circuit development, function, and behavior in a precise manner. "A hallmark of the central nervous system is the diversity of different cell types that are responsible for so many different functions," said Claude Desplan, Silver Professor of Biology and Neural Science at NYU and the study's senior author. Previous research in Desplan's lab used single-cell sequencing to determine that there are approximately 200 cell types in the developing fly's visual system. Single-cell sequencing reveals gene expression, so when cells have the same gene expression patterns, they are likely doing the same job and are therefore the same cell type. Scientists could identify roughly half of the 200 cell types in the developing fly's visual system based on their gene expression and prior studies, but they lacked a way to more easily study and label the other 100 cell types. Existing tools that allowed precise manipulation of neural circuits of adult fruit flies often failed to label the same neurons during development, rendering these tools unfit to study cells in the developing brain. "Moreover, the previous approach to identifying cell types involves laborious testing of numerous gene candidate combinations. We knew we needed a much more efficient approach to label specific cell types, and were able to tap into the growing amount of single-cell sequencing data that is available," said Yu-Chieh David Chen, a postdoctoral associate in NYU's Department of Biology and the study's first author. Chen and his colleagues created a tool that takes advantage of the extensive single-cell sequencing data for the developing fly visual system to identify genes -- and combinations of genes -- that are exclusively expressed in certain cell types. To find a cell type, researchers typically look for genetic markers, or single genes that are specific to a cell type. But often a gene will be expressed in multiple cell types, making it difficult to use one gene to differentiate between them. The tool the NYU researchers developed uses a slightly different approach: finding two genes that overlap only in one cell type. By feeding single-cell RNA sequencing data into an algorithm they created, the researchers systematically identified pairs of genes that are uniquely expressed in the majority of cell types in the fruit fly's visual system at multiple stages of development. One such gene pair led to the discovery of MeSps, a brand-new cell type. "Despite a long history of studying the fruit fly's visual system, we had never seen this cell type before," said Chen. While future research will delve into the development and function of MeSps -- for instance, whether it detects color, motion, or other features of light -- this avenue of research will be made possible by the new tools. The researchers note that their tools can also be used to study other systems beyond vision in the developing fly, as long as single-cell data are available. Moreover, their logic of finding marker gene pairs instead of one single marker gene can be applied in research in other species. "Instead of looking for a single good marker gene, a simple tweak of just looking at two genes can achieve high cell-type specificity," said Chen. "This pioneering and efficient approach provides exceptional tools for the field of neuroscience to investigate developmental questions with high precision," said Desplan. In addition to Chen and Desplan, study authors include Yen-Chung Chen, Raghuvanshi Rajesh, and undergraduate students Nathalie Shoji and Maisha Jacy of NYU; Haluk Lacin of University of Missouri-Kansas City; and Ted Erclik of the University of Toronto-Mississauga. The research was supported by grants from the National Institutes of Health (R01-EY013010, R01-EY13012, and F32-EY032750).

A new study analyzing romantic first impressions shows that compatibility and popularity among the dating pool are influential in shaping who people pursue as potential romantic partners. A new University of California, Davis, study analyzing romantic first impressions shows that compatibility and popularity among the dating pool are influential in shaping who people pursue as potential romantic partners. Although popularity and compatibility have been studied in established romantic relationships, in one of the first studies of its kind, UC Davis researchers explored whether these and other types of romantic first impressions affected later romantic outcomes. Researchers found that first impressions tend to linger, shaping whether people desired further contact with potential romantic partners after an initial meeting. The study was published Oct. 31in the Proceedings of the National Academy of Sciences. "Although we expected popularity to be an important factor in the study, we were amazed to find that a good first impression is not just a popularity contest, it's also about compatibility, even when people are still getting to know each other," said Alexander Baxter, a UC Davis doctoral student in psychology and co-author of the study. "In other words, although it helps to be popular when it comes to getting a second date, having a unique connection with a potential partner can be just as important." Assessed during speed dates The researchers asked more than 550 speed-daters, including some men who date men, to rate their romantic interest in the potential partners they met. The participants, all from the United States or Canada, included both college students and people attending a comic book convention, who cumulatively attended more than 6,600 speed-dates during the experiment. "Representation really matters in psychology research, and one of the strengths of our study is that we included a subsample of men who date men that attended an all-male speed-dating event," Baxter said. "This means that our findings generalize not only to male-female relationships, but also to male-male relationships too. We hope that future studies will consider other diverse types of relationships." After the speed-dating event, researchers surveyed the participants over the next two to three months to assess whether they dated any of the potential partners that they met and how their romantic feelings changed over time. Researchers used a statistical model to test whether later romantic outcomes were predicted by three factors that affect how romantic first impressions form -- selectivity, popularity and compatibility. In other words, they looked at patterns of initial desire that were observed during the speed-dates, and assessed whether these factors differently predicted whether people later pursued a relationship with the potential partners that they met. The factors assessed were: The results showed that people were particularly likely to pursue a romantic relationship with those who were popular and those they were compatible with. Selectivity played a relatively small role, with more romantically outgoing individuals being slightly more likely than less outgoing people to pursue their speed-dating matches, according to the study. In addition to Baxter, who is also a researcher with the California National Primate Research Center at UC Davis, co-authors of the study include Paul Eastwick, professor of psychology and director of the Attraction and Relationships Research Laboratory, UC Davis; Professor Karen L. Bales, of the primate center and Department of Neurobiology, Physiology, and Behavior, and Department of Psychology, UC Davis; Jessica A. Maxwell, School of Psychology, University of Auckland, Auckland, New Zealand; Eli J. Finkel, Department of Psychology, Kellogg School of Management, Northwestern University, Evanston, Illinois; and Emily A. Impett, Department of Psychology, University of Toronto Mississauga, Ontario, Canada. This work was supported by a grant from The Love Consortium, The John Templeton Foundation (grant 61280) and the National Science Foundation.