Adaptive Changes in Hemoglobin Function in High-Altitude Tibetan Canids Were Derived via Gene Conversion and Introgression
| Autor: | Yingzhong Yang, Quan-Yu Yang, Ga Qin, Jay F. Storz, Anthony V. Signore, Hideaki Moriyama, Ri-Li Ge |
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| Rok vydání: | 2019 |
| Předmět: |
0106 biological sciences
Models Molecular Pseudogene Acclimatization Gene Conversion introgression Introgression Biology Genetic Introgression 010603 evolutionary biology 01 natural sciences Genome 03 medical and health sciences Hemoglobins Genetic variation Genetics Animals Gene conversion Allele Molecular Biology Gene Ecology Evolution Behavior and Systematics Discoveries high-altitude 030304 developmental biology Canidae 0303 health sciences hypoxia Altitude Tibetan wolf hemoglobin Tibetan mastiff Phenotype Amino Acid Substitution Evolutionary biology Mutation |
| Zdroj: | Molecular Biology and Evolution |
| ISSN: | 1537-1719 |
| Popis: | A key question in evolutionary biology concerns the relative importance of different sources of adaptive genetic variation, such as de novo mutations, standing variation, and introgressive hybridization. A corollary question concerns how allelic variants derived from these different sources may influence the molecular basis of phenotypic adaptation. Here, we use a protein-engineering approach to examine the phenotypic effect of putatively adaptive hemoglobin (Hb) mutations in the high-altitude Tibetan wolf that were selectively introgressed into the Tibetan mastiff, a high-altitude dog breed that is renowned for its hypoxia tolerance. Experiments revealed that the introgressed coding variants confer an increased Hb–O2 affinity in conjunction with an enhanced Bohr effect. We also document that affinity-enhancing mutations in the β-globin gene of Tibetan wolf were originally derived via interparalog gene conversion from a tandemly linked β-globin pseudogene. Thus, affinity-enhancing mutations were introduced into the β-globin gene of Tibetan wolf via one form of intragenomic lateral transfer (ectopic gene conversion) and were subsequently introduced into the Tibetan mastiff genome via a second form of lateral transfer (introgression). Site-directed mutagenesis experiments revealed that the increased Hb–O2 affinity requires a specific two-site combination of amino acid replacements, suggesting that the molecular underpinnings of Hb adaptation in Tibetan mastiff (involving mutations that arose in a nonexpressed gene and which originally fixed in Tibetan wolf) may be qualitatively distinct from functionally similar changes in protein function that could have evolved via sequential fixation of de novo mutations during the breed’s relatively short duration of residency at high altitude. |
| Databáze: | OpenAIRE |
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