We have examined the phylogeographical distribution of chloroplast DNA (cpDNA) lineages of Fouquieria columnaris (Kellogg) Kellogg ex Curran (Fouquieriaceae) in the Sonoran Desert, to understand how historical climatic and/or geological changes have influenced genetic patterns in the species. Using two chloroplast intergenic DNA spacers (psbJ-petA and ndhF-rpl32), we found low levels of nucleotide diversity (π = 0.0025) but high levels of haplotype diversity (h = 0.9339). Analysis of 28 haplotypes revealed four lineages, one belonging to the continental massif and three to the peninsula of Baja California. This structure may be explained and dated by three events: (1) formation of the Gulf of California during the late Miocene (7.24 Mya), (2) activity of the Tres Vírgenes volcanic field (1.20 Mya) and (3) opening of the mid-peninsula seaway during the late Pleistocene (1.53 Mya). Furthermore, the cpDNA lineages show evidence for population contraction during the Last Glacial Maximum, with a subsequent population expansion in the Holocene.

中文翻译：

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基于叶绿体DNA的Sonoran沙漠标志性树Cirio（Fouquieria columnaris）的系统记录和遗传结构

我们检查了索诺兰沙漠中的柱形杜鹃（Fouquieria columnaris（Kellogg））鳞翅目（Fouquieriaceae）的叶绿体DNA（cpDNA）谱系的系统地理分布，以了解历史气候和/或地质变化如何影响该物种的遗传模式。使用两个叶绿体基因间DNA间隔子（psbJ-petA和ndhF-rpl32），我们发现核苷酸多样性水平较低（π= 0.0025），而单倍型多样性水平较高（h = 0.9339）。对28个单倍型的分析揭示了四个谱系，一个谱系为大陆块，三个谱系为下加利福尼亚州的半岛。这种结构可以通过以下三个事件来解释和注明日期：（1）中新世晚期（7.24 Mya）期间加利福尼亚湾的形成，（2）TresVírgenes火山场（1.20 Mya）的活动，以及（3）在更新世晚期（1.53 Mya），半岛中部海道。此外，cpDNA谱系显示出在最后一次冰河期最大时期人口收缩的证据，随后在全新世中人口膨胀。