Annual Review of Animal Biosciences最新文献

Mammalian sperm are deposited in the vagina or the cervix/uterus at coitus or at artificial insemination, and the fertilizing sperm move through the female reproductive tract to the ampulla of the oviduct, the site of fertilization. But the destination of most sperm is not the oviduct. Most sperm are carried by retrograde fluid flow to the vagina, are phagocytosed, and/or do not pass barriers on the pathway to the oviduct. The sperm that reach the site of fertilization are the exceptions and winners of one of the most stringent selection processes in nature. This review discusses the challenges sperm encounter and how the few sperm that reach the site of fertilization overcome them. The sperm that reach the goal must navigate viscoelastic fluid, swim vigorously and cooperatively along the walls of the female tract, avoid the innate immune system, and respond to potential cues to direct their movement.

Giant pandas and red pandas are endangered species with similar specialized bamboo diet and partial sympatric distribution in China. Over the last two decades, the rapid development of genomics and metagenomics research on these species has enriched our knowledge of their biology, ecology, physiology, genetics, and evolution, which is crucial and useful for their conservation. We describe the evolutionary history, endangerment processes, genetic diversity, and population structure of wild giant pandas and two species of red pandas (Chinese and Himalayan red pandas). In addition, we explore how genomics and metagenomics studies have provided insight into the convergent adaptation of pandas to the specialized bamboo diet. Finally, we discuss how these findings are applied to effective conservation management of giant and red pandas in the wild and in captivity to promote the long-term persistence of these species.

Microbes and animals have a symbiotic relationship that greatly influences nutrient uptake and animal health. This relationship can be studied using selections of microbes termed synthetic communities, or SynComs. SynComs are used in many different animal hosts, including agricultural animals, to investigate microbial interactions with nutrients and how these affect animal health. The most common host focuses for SynComs are currently mouse and human, from basic mechanistic research through to translational disease models and live biotherapeutic products (LBPs) as treatments. We discuss SynComs used in basic research models and findings that relate to human and animal health and nutrition. Translational use cases of SynComs are discussed, followed by LBPs, especially within the context of agriculture. SynComs still face challenges, such as standardization for reproducibility and contamination risks. However, the future of SynComs is hopeful, especially in the areas of genome-guided SynCom design and custom SynCom-based treatments.

Genomic data are becoming increasingly affordable and easy to collect, and new tools for their analysis are appearing rapidly. Conservation biologists are interested in using this information to assist in management and planning but are typically limited financially and by the lack of genomic resources available for non-model taxa. It is therefore important to be aware of the pitfalls as well as the benefits of applying genomic approaches. Here, we highlight recent methods aimed at standardizing population assessments of genetic variation, inbreeding, and forms of genetic load and methods that help identify past and ongoing patterns of genetic interchange between populations, including those subjected to recent disturbance. We emphasize challenges in applying some of these methods and the need for adequate bioinformatic support. We also consider the promises and challenges of applying genomic approaches to understand adaptive changes in natural populations to predict their future adaptive capacity.

Selective breeding of resilient organisms is an emerging topic in marine conservation. It can help us predict how species will adapt in the future and how we can help restore struggling populations effectively in the present. Scleractinian corals represent a potential tractable model system given their widescale phenotypic plasticity across fitness-related traits and a reproductive life history based on mass synchronized spawning. Here, I explore the justification for breeding in corals, identify underutilized pathways of acclimation, and highlight avenues for quantitative targeted breeding from the coral host and symbiont perspective. Specifically, the facilitation of enhanced heat tolerance by targeted breeding of plasticity mechanisms is underutilized. Evidence from theoretical genetics identifies potential pitfalls, including inattention to physical and genetic characteristics of the receiving environment. Three criteria for breeding emerge from this synthesis: selection from warm, variable reefs that have survived disturbance. This information will be essential to protect what we have and restore what we can.

Extensive knowledge gains from research worldwide over the 25 years since the discovery of chytridiomycosis can be used for improved management. Strategies that have saved populations in the short term and/or enabled recovery include captive breeding, translocation into disease refugia, translocation from resistant populations, disease-free exclosures, and preservation of disease refuges with connectivity to previous habitat, while antifungal treatments have reduced mortality rates in the wild. Increasing host resistance is the goal of many strategies under development, including vaccination and targeted genetic interventions. Pathogen-directed strategies may be more challenging but would have broad applicability. While the search for the silver bullet solution continues, we should value targeted local interventions that stop extinction and buy time for evolution of resistance or development of novel solutions. As for most invasive species and infectious diseases, we need to accept that ongoing management is necessary. For species continuing to decline, proactive deployment and assessment of promising interventions are more valid than a hands-off, do-no-harm approach that will likely allow further extinctions.

The bare-nosed wombat is an iconic Australian fauna with remarkable biological characteristics and mythology. This solitary, muscular, fossorial, herbivorous marsupial from southeast Australia has continent and continental island subspeciation. Vombatiformes also contains hairy-nosed wombats (Lasiorhinus spp.); koala (Phascolarctos cinereus); and extinct megafauna, Phascolonus gigas (giant wombat), Diprotodon, and Thylacoleo (marsupial lion). Culturally important to Aboriginal people, bare-nosed wombats engineer ecosystems through digging, grazing, and defecation. Olfaction and cubic fecal aggregations appear critical for communication, including identity, courtship, and mating. Though among the largest fossorial herbivores, they have a nutrient-poor diet, a home range up to an order of magnitude smaller than expected, and a metabolism among the lowest extreme for mammals >10 kg. Metabolic depression may confer advantages over resource competitors and fossorial lifestyle protection from predators, fires, and climatic extremes. Bare-nosed wombats are loved and persecuted by European colonists. Recent population increases may reflect softening attitudes toward, and greater protections of, bare-nosed wombats.

Though narwhal have survived multiple ice ages, including 2.5 Ma and the last interglacial period with warming temperatures, Arctic climate change during the Anthropocene introduces new challenges. Despite their evolutionary connection to Arctic Pleistocene fossils, narwhal archeocete ancestors from the Pliocene (Bohaskaia monodontoides) and Miocene (Denebola and Odobenocetopsidae) inhabited warm waters. Narwhal Arctic adaptation holds valuable insights into unique traits, including thin skin; extreme diving capacity; and a unique straight, spiraled, and sensory tooth organ system. Inaccessible weather, ice conditions, and darkness limit scientific studies, though Inuit knowledge adds valuable observations of narwhal ecology, biology, and behavior. Existing and future studies in myriad fields of physical, chemical, biological, and genetic science, combined and integrated with remote sensing and imaging technologies, will help elucidate narwhal evolution, biology, and adaptation. When integrated with Qaujimajatuqangit, "the Inuit way of knowing," these studies help describe interesting biologic expressions of the narwhal.