Genetic diversity maintained among fragmented populations of a tree undergoing range contraction.
Genetic diversity maintained among fragmented populations of a tree undergoing range contraction.
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DOI：
10.1038/s41437-018-0132-8
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发表时间：
2018-10
期刊：
影响因子：
3.8
通讯作者：
Buggs RJA
中科院分区：
文献类型：
--
作者：
Borrell JS;Wang N;Nichols RA;Buggs RJA
矮桦（Betula nana）在北方广泛分布，但在英国已大幅减少，那里的种群数量现在高度分散。我们使用突变率不同的标记分析了这些碎片化群体的遗传多样性：传统的微卫星标记 (PCR-SSR)、RADseq 生成的转换和颠换 SNP (RAD-SNP) 以及从 RADseq 读段中挖掘的微卫星标记 (RAD-SSR)。我们通过人口普查和遗传调查中发现的连锁不平衡间接估计了当前的人口规模。这两种类型的估计高度相关。总体而言，我们发现英国的遗传多样性仅略低于人口众多且连续的斯堪的纳维亚半岛的类似地区。虽然英国碎片的整体保持着接近斯堪的纳维亚人口的多样性水平，但他们个体却逐渐疏远并失去了多样性；尤其是人口较少的地区。美国广播公司（ABC）基于合并模型的分析支持英国通过冰期后重新殖民保持高水平遗传多样性的人口情景。这种多样性随后被划分为种群碎片，这些种群碎片最近以与当前种群规模估计相对应的速度失去了多样性。我们的结论是，英国种群保留了足够的遗传资源，可以作为保护和重新种植计划的基础。使用具有不同突变率的标记为我们提供了比单独一组标记更大的信心和洞察力，我们认为 RAD-SSR 作为具有明确确定偏差的高突变率标记集特别有用，这些标记集广泛可用，但在现有 RAD 数据集中经常被忽视。
Dwarf birch (Betula nana) has a widespread boreal distribution but has declined significantly in Britain where populations are now highly fragmented. We analyzed the genetic diversity of these fragmented populations using markers that differ in mutation rate: conventional microsatellites markers (PCR-SSRs), RADseq generated transition and transversion SNPs (RAD-SNPs), and microsatellite markers mined from RADseq reads (RAD-SSRs). We estimated the current population sizes by census and indirectly, from the linkage-disequilibrium found in the genetic surveys. The two types of estimate were highly correlated. Overall, we found genetic diversity to be only slightly lower in Britain than across a comparable area in Scandinavia where populations are large and continuous. While the ensemble of British fragments maintain diversity levels close to Scandinavian populations, individually they have drifted apart and lost diversity; particularly the smaller populations. An ABC analysis, based on coalescent models, favors demographic scenarios in which Britain maintained high levels of genetic diversity through post-glacial re-colonization. This diversity has subsequently been partitioned into population fragments that have recently lost diversity at a rate corresponding to the current population-size estimates. We conclude that the British population fragments retain sufficient genetic resources to be the basis of conservation and re-planting programmes. Use of markers with different mutation rates gives us greater confidence and insight than one marker set could have alone, and we suggest that RAD-SSRs are particularly useful as high mutation-rate marker set with a well-specified ascertainment bias, which are widely available yet often neglected in existing RAD datasets.
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影响因子：
3.7
作者：
Baird NA;Etter PD;Atwood TS;Currey MC;Shiver AL;Lewis ZA;Selker EU;Cresko WA;Johnson EA
通讯作者：
Johnson EA
影响因子：
3.1
作者：
Coates, Brad S.;Sumerford, Douglas V.;Lewis, Leslie C.
通讯作者：
Lewis, Leslie C.
影响因子：
5.8
作者：
Cornuet, Jean-Marie;Pudlo, Pierre;Estoup, Arnaud
通讯作者：
Estoup, Arnaud
影响因子：
4.9
作者：
Bradbury, Ian R.;Hamilton, Lorraine C.;Verspoor, Eric
通讯作者：
Verspoor, Eric
影响因子：
7.7
作者：
Excoffier, Laurent;Lischer, Heidi E. L.
通讯作者：
Lischer, Heidi E. L.