{"database":"biostudies-literature","file_versions":[],"scores":null,"additional":{"submitter":["Graham AM"],"funding":["NEI NIH HHS","NIDDK NIH HHS","NHGRI NIH HHS","National Institutes of Health","Ministry for Science and Art Hessen","NIGMS NIH HHS"],"pagination":["3269-3277.e4"],"full_dataset_link":["https://www.ebi.ac.uk/biostudies/studies/S-EPMC12697247"],"repository":["biostudies-literature"],"omics_type":["Unknown"],"volume":["35(13)"],"pubmed_abstract":["The invasion of specialized ecological niches can cause drastic changes to selection regimes, resulting in genomic and phenotypic transformation.<sup>1</sup> High-altitude habitats offer an excellent opportunity to investigate the genetic basis of local adaptation,<sup>2</sup><sup>,</sup><sup>3</sup> as the repeated specialization of multiple lineages for high altitude has produced striking examples of convergent evolution, adaptation, and changes in their underlying genes.<sup>4</sup><sup>,</sup><sup>5</sup><sup>,</sup><sup>6</sup> Although enlightening, this focus on adaptation has left aspects of evolution in high-altitude locations understudied-including the role of gene loss and pseudogenization, maladaptation and trait loss, and physiological aspects outside of respiration and gas exchange. To characterize how mammals responded to high altitude in a new, unbiased way, we screened the genomes of 27 species living exclusively at high altitude (>1,000-1,500 m) and their lowland relatives for inactivated pseudogenes or lost genes.<sup>7</sup> Genes that convergently lost function in high-altitude species were highly enriched for olfactory receptor (OR) genes, with an average reduction of ∼23% of OR repertoire in high-altitude species. No such trend was found for genes involved in pheromone detection and taste perception. In addition to OR loss, cranial endocasts show the brains of high-altitude species have on average ∼18% smaller olfactory bulbs relative to lowland relatives. Together, these repeated evolutionary outcomes suggest a general relaxation of constraint on olfaction at altitude, perhaps due to reduced odorant diversity in high-altitude environments or reduced effectiveness of mammalian olfactory physiology in thin, dry, or cold air."],"journal":["Current biology : CB"],"pubmed_title":["Convergent reduction of olfactory genes and olfactory bulb size in mammalian species at altitude."],"pmcid":["PMC12697247"],"funding_grant_id":["R01 EY030546","LOEWE/1/10/519/03/03.001(0014)/52","R00 GM144774","K99 GM144774","T32 DK007115","R01 HG009299"],"pubmed_authors":["Graham AM","Hiller M","Harrington A","Clark N","Kirilenko B","Huff C","Saputra E","Presnell JS"],"additional_accession":[]},"is_claimable":false,"name":"Convergent reduction of olfactory genes and olfactory bulb size in mammalian species at altitude.","description":"The invasion of specialized ecological niches can cause drastic changes to selection regimes, resulting in genomic and phenotypic transformation.<sup>1</sup> High-altitude habitats offer an excellent opportunity to investigate the genetic basis of local adaptation,<sup>2</sup><sup>,</sup><sup>3</sup> as the repeated specialization of multiple lineages for high altitude has produced striking examples of convergent evolution, adaptation, and changes in their underlying genes.<sup>4</sup><sup>,</sup><sup>5</sup><sup>,</sup><sup>6</sup> Although enlightening, this focus on adaptation has left aspects of evolution in high-altitude locations understudied-including the role of gene loss and pseudogenization, maladaptation and trait loss, and physiological aspects outside of respiration and gas exchange. To characterize how mammals responded to high altitude in a new, unbiased way, we screened the genomes of 27 species living exclusively at high altitude (>1,000-1,500 m) and their lowland relatives for inactivated pseudogenes or lost genes.<sup>7</sup> Genes that convergently lost function in high-altitude species were highly enriched for olfactory receptor (OR) genes, with an average reduction of ∼23% of OR repertoire in high-altitude species. No such trend was found for genes involved in pheromone detection and taste perception. In addition to OR loss, cranial endocasts show the brains of high-altitude species have on average ∼18% smaller olfactory bulbs relative to lowland relatives. Together, these repeated evolutionary outcomes suggest a general relaxation of constraint on olfaction at altitude, perhaps due to reduced odorant diversity in high-altitude environments or reduced effectiveness of mammalian olfactory physiology in thin, dry, or cold air.","dates":{"release":"2025-01-01T00:00:00Z","publication":"2025 Jul","modification":"2026-06-06T02:19:48.797Z","creation":"2026-05-24T03:12:14.072Z"},"accession":"S-EPMC12697247","cross_references":{"pubmed":["40562037"],"doi":["10.1016/j.cub.2025.05.061"]}}