A chloroplast DNA Phylogenetic study of the eastern Asia‐eastern North America disjunct sectionRytidospermumofMagnolia(Magnoliaceae)

Abstract

Chloroplast DNA restriction site variation of ten endonucleases was examined among all ten species or varieties of the eastern Asia–eastern North America disjunct section Rytidospermum of Magnolia. Representatives from seven of the other ten sections of Magnolia and four related genera (Liriodendron, Manglietia, Michelia, and Talauma) were also included in the survey. A cladistic analysis of 200 variable sites using Wagner parsimony yielded 11 equally most parsimonious trees with a consistency index of 0.793 and a retention index of 0.870. The section Rytidospermum is polyphyletic in these trees. Magnolia tripetala from the southeastern U.S. is the only American species that has a sister relationship to the Asian taxa, M. hypoleuca, M. officinalis var. officinalis, M. officinalis var. biloba, and M. rostrata. Other American taxa in the section fall into two lineages, with M. macrophylla var. macrophylla, M. macrophylla var. ashei, and M. macrophylla var. dealbata in one, and M. fraseri var. fraseri and M. fraseri var. pyramidata in the other. They are not related to the Asian species as previously believed. The relationships revealed here are in agreement with morphological, allozymic, and cross compatibility data. These results demonstrate that a robust phylogenetic hypothesis is an important prerequisite for understanding biogeographic patterns.

The Complete Plastid Genome of Magnolia zenii and Genetic Comparison to Magnoliaceae species

“…Although our taxon sampling was insufficient to perform a robust phylogenetic analysis of Magnolia , our data do provide information for future phylogenetic studies within the genus. Our discovery of gene regions with high polymorphism not used by previous phylogenetic studies in Magnolia [11,20,21,22,65] provides exciting avenues for future phylogenetic and evolutionary studies in this genus. It is now necessary that work be done to design the markers for these mutation hotspots to test their value in molecular studies.…”

Comparison of Magnoliaceae Plastomes: Adding Neotropical Magnolia to the Discussion

“…Indeed, although databases, such as POWO [ 65 ], record 339 accepted species, the largest phylogenetic studies published to date include only between 86 and 99 of them [ 43 , 54 , 57 ]. Some authors [ 54 , 55 , 66 , 67 , 68 , 69 ] suggested that a study including a broader taxon sampling is necessary to address questions that have not been resolved by studies based on Sanger sequencing (i.e., chloroplast and nuclear DNA markers). Such is the case of the relationships between the Neotropical Magnolia taxa or the deep relationships within the subgenus Magnolia , which, based on several molecular studies, has been shown not to be monophyletic [ 43 , 54 , 55 , 69 ].…”

Chloroplast genome and historical biogeography of the three Magnolias

“…Besides, cp-genome were widely used in species evolution [22], phylogenetic [23][24][25] and biogeographic studies [26][27][28]. Meanwhile, organismic and environmental processes played a major role in organismal evolution [29][30]. Currently, with the rapid development of high throughput sequencing technologies, made it possible for reseachers to obtain cp genomic sequences to study species evolution, phylogenetic and biogeographic [31].Therefore, whole cp genome of M. hypoleuca was urgently needed, which might signi cantly provide an insight in plant phylogenetic relationships and contributed to the, domestication, and utilization of Magnoliaceae plants.…”