Background： In coevolutionary interactions between brood parasites and their hosts, host parents are under strong selection to evolve defenses against parasitism. Egg rejection is an efficient and common defense agai...Background： In coevolutionary interactions between brood parasites and their hosts, host parents are under strong selection to evolve defenses against parasitism. Egg rejection is an efficient and common defense against parasitism, although some apparently suitable hosts do not reject cuckoo eggs.Methods： Sparrows Ploceidae are widespread throughout the Old World, and they have a suitable diet for rearing cuckoos, but still they are rarely exploited by brood parasites. To solve such puzzle, we conducted artificial parasitism and cross-fostering experiments in Russet Sparrow （Posset cinnomomeus）.Results： The present study showed that Russet Sparrows have no egg recognition ability, but recognize their own nestlings and eject alien chicks or starve them to death. They may use visual cues in chick recognition, although they accept sister species Tree Sparrow （Posset montonus）.Conclusions： By rejecting nestlings of foreign species, Russet Sparrows have succeeded to escape from the brood parasitism by cuckoos and other parasites. Our studies shed light on the puzzle why some species are not utilized by cuckoo parasites as hosts,展开更多
Over the last 30 years,aquaculture has become the fastest growing form of agriculture production in the world,but its development has been hampered by a diverse range of pathogenic viruses.During the last decade,a lar...Over the last 30 years,aquaculture has become the fastest growing form of agriculture production in the world,but its development has been hampered by a diverse range of pathogenic viruses.During the last decade,a large number of viruses from aquatic animals have been identified,and more than 100 viral genomes have been sequenced and genetically characterized.These advances are leading to better understanding about antiviral mechanisms and the types of interaction occurring between aquatic viruses and their hosts.Here,based on our research experience of more than 20 years,we review the wealth of genetic and genomic information from studies on a diverse range of aquatic viruses,including iridoviruses,herpesviruses,reoviruses,and rhabdoviruses,and outline some major advances in our understanding of virus–host interactions in animals used in aquaculture.展开更多
A virus that can cause a global pandemic must be highly adaptive to human conditions.Such adaptation is not likely to have emerged suddenly but,instead,may have evolved step by step with each step favored by natural s...A virus that can cause a global pandemic must be highly adaptive to human conditions.Such adaptation is not likely to have emerged suddenly but,instead,may have evolved step by step with each step favored by natural selection.It is thus necessary to develop a theory about the origin in order to guide the search.Here,we propose such a model whereby evolution occurs in both the virus and the hosts(where the evolution is somatic;i.e.,in the immune system).The hosts comprise three groups–the wild animal hosts,the nearby human population,and farther-away human populations.The theory suggests that the conditions under which the pandemic has initially evolved are:(i)an abundance of wild animals in the place of origin(PL_(0));(ii)a nearby human population of low density;(iii)frequent and long-term animal-human contacts to permit step-by-step evolution;and(iv)a level of herd immunity in the animal and human hosts.In this model,the evolving virus may have regularly spread out of PL_(0) although such invasions often fail,leaving sporadic cases of early infections.The place of the first epidemic(PL_(1)),where humans are immunologically naïve to the virus,is likely a distance away from PL_(0).Finally,this current model is only a first attempt and more theoretical models can be expected to guide the search for the origin of SARS-CoV-2.展开更多
基金supported by the National Natural Science Foundation of China(Nos.31672303 to CY,31472013 and 31772453 to WL)
文摘Background： In coevolutionary interactions between brood parasites and their hosts, host parents are under strong selection to evolve defenses against parasitism. Egg rejection is an efficient and common defense against parasitism, although some apparently suitable hosts do not reject cuckoo eggs.Methods： Sparrows Ploceidae are widespread throughout the Old World, and they have a suitable diet for rearing cuckoos, but still they are rarely exploited by brood parasites. To solve such puzzle, we conducted artificial parasitism and cross-fostering experiments in Russet Sparrow （Posset cinnomomeus）.Results： The present study showed that Russet Sparrows have no egg recognition ability, but recognize their own nestlings and eject alien chicks or starve them to death. They may use visual cues in chick recognition, although they accept sister species Tree Sparrow （Posset montonus）.Conclusions： By rejecting nestlings of foreign species, Russet Sparrows have succeeded to escape from the brood parasitism by cuckoos and other parasites. Our studies shed light on the puzzle why some species are not utilized by cuckoo parasites as hosts,
基金supported by grants from the National Natural Science Foundation of China(31430091)the National Key Basic Research Program(2010CB126303)the Project of State Key Laboratory of Freshwater Ecology and Biotechnology(2011FBZ12)
文摘Over the last 30 years,aquaculture has become the fastest growing form of agriculture production in the world,but its development has been hampered by a diverse range of pathogenic viruses.During the last decade,a large number of viruses from aquatic animals have been identified,and more than 100 viral genomes have been sequenced and genetically characterized.These advances are leading to better understanding about antiviral mechanisms and the types of interaction occurring between aquatic viruses and their hosts.Here,based on our research experience of more than 20 years,we review the wealth of genetic and genomic information from studies on a diverse range of aquatic viruses,including iridoviruses,herpesviruses,reoviruses,and rhabdoviruses,and outline some major advances in our understanding of virus–host interactions in animals used in aquaculture.
基金supported by the National Natural Science Foundation of China (31730046, 91731000, 31900417, and 81972691)Guangdong Basic and Applied Basic Research Foundation (2020B1515020030, 2019A1515010708)the National Key Research and Development Project of China (2020YFC0847000)
文摘A virus that can cause a global pandemic must be highly adaptive to human conditions.Such adaptation is not likely to have emerged suddenly but,instead,may have evolved step by step with each step favored by natural selection.It is thus necessary to develop a theory about the origin in order to guide the search.Here,we propose such a model whereby evolution occurs in both the virus and the hosts(where the evolution is somatic;i.e.,in the immune system).The hosts comprise three groups–the wild animal hosts,the nearby human population,and farther-away human populations.The theory suggests that the conditions under which the pandemic has initially evolved are:(i)an abundance of wild animals in the place of origin(PL_(0));(ii)a nearby human population of low density;(iii)frequent and long-term animal-human contacts to permit step-by-step evolution;and(iv)a level of herd immunity in the animal and human hosts.In this model,the evolving virus may have regularly spread out of PL_(0) although such invasions often fail,leaving sporadic cases of early infections.The place of the first epidemic(PL_(1)),where humans are immunologically naïve to the virus,is likely a distance away from PL_(0).Finally,this current model is only a first attempt and more theoretical models can be expected to guide the search for the origin of SARS-CoV-2.
