Intraspecific diversification in North American Boechera stricta (=Arabis drummondii), Boechera xdivaricarpa, and Boechera holboellii (Brassicaceae) inferred from nuclear and chloroplast molecular markers -: An integrative approach
Intraspecific diversification in North American Boechera stricta (=Arabis drummondii), Boechera xdivaricarpa, and Boechera holboellii (Brassicaceae) inferred from nuclear and chloroplast molecular markers -: An integrative approach
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DOI：
10.3732/ajb.91.12.2087
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发表时间：
2004-12-01
影响因子：
3
通讯作者：
Koch, MA
中科院分区：
文献类型：
--
作者：
Dobes, C;Mitchell-Olds, T;Koch, MA
我们使用倍性水平估计值、等位基因微卫星变异、质体基因组非编码区（cpDNA）以及核核糖体DNA（ITS）的内部转录间隔区I和2的序列等信息，对北美Boechera stricta、Boechera holboellii及其杂种Boechera X divaricarpa进行了联合进化分析。通过比较花粉大小和7个微卫星位点的等位基因数，估计了植物标本的体细胞倍性水平。结果表明，B. stricta和B. holboellii在遗传上彼此不同，尽管我们也发现了两个亲本物种之间偶尔基因渗入的证据。B的微卫星模式。来自北美东北部的stricta在遗传上与西方种群不同，这表明在冰川避难所沿着连续冰盾的东南边缘隔离。微卫星支持B的最近起源。Xdivarapa.大多数二倍体B的nrDNA与cpDNA遗传变异一致。holboellii种质表明在多态性B内有一个基本的有性进化单位。霍尔伯埃利群遗传上不同的家系间的杂交在多倍体B的形成中起着重要作用。holboellii。多倍体B的频率。在美国南部，holhoellii的含量要高得多。这一趋势对应于派生的叶绿体单倍型的南部分布，表明在内华达州和南落基山脉的殖民化的多倍体和相关的无融合生殖的进化优势。
We performed a combined evolutionary analysis of North American Boechera stricta, Boechera holboellii, and their hybrid Boechera X divaricarpa using information on ploidy level estimators, allelic microsatellite variation, noncoding regions of the plastidic genome (cpDNA), and sequences of the internal transcribed spacers I and 2 of the nuclear ribosomal DNA (ITS). Somatic ploidy levels of herbarium specimens were estimated based on comparison of pollen size and the number of alleles per locus at seven microsatellites. Results indicate that B. stricta and B. holboellii are genetically distinct from each other, although we also find evidence for occasional introgression between both parental species. Microsatellite patterns for B. stricta from northeastern North America are genetically distinct from western populations, suggesting isolation in glacial refugia along the Southeastern margin of the continuous ice shield. Microsatellites Supported recent origin of B. Xdivaricarpa. Correspondence of nrDNA with cpDNA genetic variation for the majority of diploid B. holboellii accessions Suggests a basal, sexual evolutionary unit within a polymorphic B. holboellii group. Hybridization of genetically distinct lineage(s) evidently played an important role in the establishment of polyploid B. holboellii. Frequency of polyploid B. holhoellii is substantially higher in the southern United States. This trend corresponds to a southerly distribution of derived chloroplast haplotypes, suggesting an evolutionary advantage of polyploidy and associated apomixis in the colonization of the Sierra Nevada and the Southern Rocky Mountains.