ダイモンジソウ（ユキノシタ科）においてハビタット多様化がもたらす遺伝的および生理生態的影響

京都大学新制・課程博士博士(人間・環境学)甲第23993号人博第1045号新制||人||245(附属図書館)2022||人博||1045(吉田南総合図書館)京都大学大学院人間・環境学研究科相関環境学専攻(主査)教授 瀬戸口 浩彰, 教授 市岡 孝朗, 教授 宮下 英明, 准教授 西川 完途, 准教授 池田 啓学位規則第4条第1項該当Doctor of Human and Environmental StudiesKyoto UniversityDGA

Development and characterization of EST-SSR markers for Saxifraga fortunei var. incisolobata (Saxifragaceae)

Premise: Saxifraga fortunei (Saxifragaceae) includes several infraspecific taxa that are ecologically and morphologically distinct. To investigate the evolutionary history of phenotypic polymorphisms in this species, we developed expressed sequence tag–simple sequence repeat (EST‐SSR) markers for S. fortunei. Methods and Results: We developed 26 polymorphic markers based on transcriptome data obtained from Illumina HiSeq 2000. Within three populations of S. fortunei var. incisolobata, the number of alleles ranged from four to 25, and the levels of observed and expected heterozygosity ranged from 0.200 to 0.847 and from 0.209 to 0.930, respectively. Furthermore, all 26 loci showed transferability for S. fortunei var. obtusocuneata and S. fortunei var. suwoensis, and 18 loci were also successfully amplified in S. acerifolia. Conclusions: These newly developed EST‐SSR markers will prove useful to infer the evolutionary history of S. fortunei var. incisolobata and its relatives in population genetic studies

Comparative analysis of spatial genetic structures in sympatric populations of two riparian plants,Saxifraga acerifoliaandSaxifraga fortunei

PREMISE: The genetic structure between plant populations is facilitated by the spatial population arrangement and limited dispersal of seed and pollen. Saxifraga acerifolia, a local endemic species in Japan, is a habitat specialist that is confined to waterfalls in riparian environments. Its sister species, Saxifraga fortunei, is a generalist that is widely distributed along riverbanks. Here, we examined sympatric populations of the two Saxifraga species to test whether the differences in habitat preference and colonization process influenced regional and local genetic structures. METHODS: To reveal genetic structures, we examined chloroplast microsatellite variations and genome-wide nucleotide polymorphisms obtained by genotyping by sequencing. We also estimated the gene flow among and within populations and performed landscape genetic analyses to evaluate seed and pollen movement and the extent of genetic isolation related to geographic distance and/or habitat differences. RESULTS: We found strong genetic structure in the specialist S. acerifolia, even on a small spatial scale (<1 km part); each population on a different waterfall in one river system had a completely different predominant haplotype. By contrast, the generalist S. fortunei showed no clear genetic differentiation. CONCLUSIONS: Our findings suggest that the level of genetic isolation was increased in S. acerifolia by the spatially fragmented habitat and limited seed and pollen dispersal over waterfalls. Habitat differentiation between the sister taxa could have contributed to the different patterns of gene flow and then shaped the contrasting genetic structures