背景:心裂,一组热带树木(约20spp.)在樟科中,有两栖-太平洋分离分布:10种分布在东南亚,而南美的热带雨林则限制了8种。以前,使用两个核标记的系统发育分析解决了拉丁美洲五个物种之间的关系。然而,亚洲物种之间的系统发育关系仍然鲜为人知。
结果:这里,我们首先确定了完整的线粒体基因组(有丝分裂基因组),质体,和C.henryi的核核糖体顺反子(nrDNA)序列,长度为1,168,029bp,154,938个基点,6495bp,分别。我们在C.henryi的有丝分裂基因组中发现了2233个重复序列和368个潜在的SSR,在其有丝分裂基因组和质体之间发现了50个同源DNA片段。基因合成分析显示,木兰的有丝分裂基因组中有大量重排,HernandiaNymphaeifolia,和C.henryi,其中只有六个保守的成簇基因。为了重建亚洲十种Caryodaphnopsis物种的关系,我们创建了三个数据集:一个是有丝分裂基因组(编码基因和十个基因间区域),另一个是质体(全基因组),另一个是核核糖体顺反子。所有的22个Caryodaphnopsis个体被分为四个,五,和基于有丝分裂基因组的六个不同的进化枝,质体,和nrDNA数据集,分别。
结论:该研究显示了Caryodaphnopsis物种的核和细胞器基因组数据内部和之间的系统发育冲突。中国河口和麻栗坡的同胞石竹物种可能与不完整的谱系分类有关,叶绿体捕获,和/或杂交,将该物种作为进化史上的一个复合体混合在一起。
BACKGROUND: Caryodaphnopsis, a group of tropical trees (ca. 20 spp.) in the family Lauraceae, has an amphi-Pacific disjunct distribution: ten species are distributed in Southeast Asia, while eight species are restricted to tropical rainforests in South America. Previously, phylogenetic analyses using two nuclear markers resolved the relationships among the five species from Latin America. However, the phylogenetic relationships between the species in Asia remain poorly known.
RESULTS: Here, we first determined the complete mitochondrial genome (mitogenome),
plastome, and the nuclear ribosomal cistron (nrDNA) sequences of C. henryi with lengths of 1,168,029 bp, 154,938 bp, and 6495 bp, respectively. We found 2233 repeats and 368 potential SSRs in the mitogenome of C. henryi and 50 homologous DNA fragments between its mitogenome and
plastome. Gene synteny analysis revealed a mass of rearrangements in the mitogenomes of Magnolia biondii, Hernandia nymphaeifolia, and C. henryi and only six conserved clustered genes among them. In order to reconstruct relationships for the ten Caryodaphnopsis species in Asia, we created three datasets: one for the mitogenome (coding genes and ten intergenic regions), another for the
plastome (whole genome), and the other for the nuclear ribosomal cistron. All of the 22 Caryodaphnopsis individuals were divided into four, five, and six different clades in the phylogenies based on mitogenome,
plastome, and nrDNA datasets, respectively.
CONCLUSIONS: The study showed phylogenetic conflicts within and between nuclear and organellar genome data of Caryodaphnopsis species. The sympatric Caryodaphnopsis species in Hekou and Malipo SW China may be related to the incomplete lineage sorting, chloroplast capture, and/or hybridization, which mixed the species as a complex in their evolutionary history.