臺灣 Petaurista 屬飛鼠的親緣地理學、族群數量變遷、與環境適應

Abstract

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Double digest restriction site associated DNA sequencing (ddRAD-seq) is an increasingly accessible tool for phylogenetic studies, with a broad range of applications, including the characterization of past population dynamics and prediction of future responses to change. However, this tool has yet to be applied to small mammal species of Taiwan, where previous phylogenetic studies have used exclusively mitochondrial DNA. The aim of my research was to assess the potential of genomic SNP data to provide a deeper understanding of small mammal phylogeography in Taiwan. Using ddRAD-seq, I explored the phylogeography of two endemic species of giant flying squirrel: Petaurista lena, the white-faced giant flying squirrel, and Petaurista grandis, the red giant flying squirrel. Contrary to previous findings, both species demonstrated significant population structure along the North-South axis. There was a strong correlation between genetic distance and spatial distance for both species; however, I found no strong relationship between genetic variation and climate or landscape factors. Demographic analyses indicated that P. lena experienced population expansion during the glacial period MIS 6 but has been declining since the early-mid Holocene. P. grandis demonstrated the opposite reaction, experiencing expansion during the climate warming of the early Holocene. These findings tell a different story than previous mitochondrial analyses, providing novel insight into the population structure and demography of Petaurista species in Taiwan. Overall, ddRAD-seq proved effective for detecting and explaining genetic variation across Taiwan; future analyses of small mammal species should consider incorporating genomic SNP data, particularly for species whose phylogeography is not well explained.