The effects of population bottlenecks on dental phenotype in extant arvicoline rodents: Implications for studies of the quaternary fossil record. (15th January 2020)

• Record Type: Journal Article
• Authors: Markova, Evgenia; Bobretsov, Anatoliy; Borodin, Aleksandr; Rakitin, Sergey; Sibiryakov, Petr; Smirnov, Nikolai; Yalkovskaya, Lidia; Zykov, Sergey
• Is Part Of: Quaternary science reviews. Volume 228(2020)
• Publication Date: 2020-01-15
• Subjects: Pleistocene -- Present -- Climate dynamics -- Biological proxies -- Small mammals -- Population decline -- Genetic drift -- Dental variation; Geology, Stratigraphic -- Quaternary -- Periodicals; Stratigraphie -- Quaternaire -- Périodiques; 551.79
• DOI: 10.1016/j.quascirev.2019.106045
• Languages: English
• ISSNs: 0277-3791

Abstract

Abstract: The consequences of population bottlenecks for dental phenotypes are studied in Arvicolinae, a subfamily of cricetid rodents widely used as a proxy of environmental change and an index group for relative dating and correlation of the Quaternary deposits throughout the Holarctic. Comparative morphological analysis reveals similar phenotypic shifts in populations of extant Dicrostonyx, Lemmus, Myopus, Microtus surviving bottlenecks in captivity or in the areas favouring genetic drift (coastal zones and islands, patchy landscapes in the mountainous areas, declining peripheral populations). Six to ten founders is enough for an isolated population to reproduce the full range of species-specific variability in fitness-related characters (crown complexity and occlusal regularity) during the first two generations, while the average values of both characters exhibit founder dependence. When lasting longer than 3 generations, bottlenecks increase diversity owing to 1) the accumulation of rare traits of complexity and regularity inherited from the founders and 2) inbreeding impacts (the loss of advanced morphology and appearance of extra elements in places of the lophs and cusplets of an ancestral cricetid molar). Founder-related and inbreeding-induced simplifications of dentition might potentially lead to biochronological discrepancies in the fossil record of Arvicolinae. To detect possible biases in biochronological data, the phenotypic markers of close breeding are identified. Application of the results to the fossil record of collared lemmings from the north of West Siberia allows hypothesising the periods of increased genetic drift in the ancestral forms of Dicrostonyx in the late Middle Pleistocene and in the early Late Pleistocene. Highlights: Bottlenecks associated with close breeding and isolation inflate dental diversity. Dental phenotype reversals are observed in biochronological index taxa. Inbreeding-induced dental aberrations are not eradicated by population dynamics. Rare dental traits are suggested as the markers of population decline in arvicolines.