Phylogeography of Camellia taliensis (Theaceae) inferred from chloroplast and nuclear DNA: insights into evolutionary history and conservation.
Phylogeography of Camellia taliensis (Theaceae) inferred from chloroplast and nuclear DNA: insights into evolutionary history and conservation.
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DOI：
10.1186/1471-2148-12-92
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发表时间：
2012-06-21
影响因子：
3.4
通讯作者：
Gao LZ
中科院分区：
文献类型：
--
作者：
Liu Y;Yang SX;Ji PZ;Gao LZ
大理茶是茶树的重要野生近缘种之一，具有重要的茶树基因资源。对该物种遗传变异和种群结构的了解，有助于了解该物种的进化历史和种质资源的保存。本文对中国的21个自然居群进行了系统的地理学研究。利用核PAL基因片段和叶绿体rp 132-trnL基因间隔区对大荔（Taliensis）进行了克隆。在rpl 32-trnL（h = 0.841; π = 0.00314）处检测到的单倍型多样性和核苷酸多样性水平几乎与在PAL（h = 0.836; π = 0.00417）处一样高。叶绿体DNA的群体亚群检测（GST = 0.988; NST = 0.989），表明相当高的遗传分化和低水平的经常性基因流通过种子种群之间。叶绿体类型的巢式进化枝地理分析表明，群体遗传结构在中国南方红豆杉中的分布与其在中国南方红豆杉中的分布相似。taliensis过去曾受到生境破碎化的影响。然而，nrDNA的中度亚群（GST = 0.222; NST = 0.301）的检测提供了有效的花粉介导的居群间基因流动和显著的地理结构的证据（NST > GST; P < 0.01）。PAL单倍型分析表明，nrDNA单倍型的地理分布格局可能是由距离隔离的限制性基因流造成的，Mantel的nrDNA单倍型检验也支持这一结论（r = 0.234，P < 0.001）。结果表明，澜沧江流域的7个种群中，氯型C1均为固定型，这表明澜沧江流域可能为该物种的远距离扩散提供了通道。我们发现C. Taliensis具有较高的遗传分化，这是由于基因流受限和生境破碎化所致。这项地理学研究为我们深入了解该物种的种群结构和种质取样的保护策略以及自然种群的原位保护提供了深刻的见解。
As one of the most important but seriously endangered wild relatives of the cultivated tea, Camellia taliensis harbors valuable gene resources for tea tree improvement in the future. The knowledge of genetic variation and population structure may provide insights into evolutionary history and germplasm conservation of the species. Here, we sampled 21 natural populations from the species' range in China and performed the phylogeography of C. taliensis by using the nuclear PAL gene fragment and chloroplast rpl32-trnL intergenic spacer. Levels of haplotype diversity and nucleotide diversity detected at rpl32-trnL (h = 0.841; π = 0.00314) were almost as high as at PAL (h = 0.836; π = 0.00417). Significant chloroplast DNA population subdivision was detected (GST = 0.988; NST = 0.989), suggesting fairly high genetic differentiation and low levels of recurrent gene flow through seeds among populations. Nested clade phylogeographic analysis of chlorotypes suggests that population genetic structure in C. taliensis has been affected by habitat fragmentation in the past. However, the detection of a moderate nrDNA population subdivision (GST = 0.222; NST = 0.301) provided the evidence of efficient pollen-mediated gene flow among populations and significant phylogeographical structure (NST > GST; P < 0.01). The analysis of PAL haplotypes indicates that phylogeographical pattern of nrDNA haplotypes might be caused by restricted gene flow with isolation by distance, which was also supported by Mantel’s test of nrDNA haplotypes (r = 0.234, P < 0.001). We found that chlorotype C1 was fixed in seven populations of Lancang River Region, implying that the Lancang River might have provided a corridor for the long-distance dispersal of the species. We found that C. taliensis showed fairly high genetic differentiation resulting from restricted gene flow and habitat fragmentation. This phylogeographical study gives us deep insights into population structure of the species and conservation strategies for germplasm sampling and developing in situ conservation of natural populations.
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影响因子：
4.9
作者：
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通讯作者：
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影响因子：
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