Reticulate evolution in the parasitic genus Cuscuta (Convolvulaceae): over and over againThis paper is one of a selection of papers published in the Special Issue on Systematics Research.

Botany ◽  
2008 ◽  
Vol 86 (8) ◽  
pp. 791-808 ◽  
Author(s):  
Saša Stefanović ◽  
Mihai Costea
Keyword(s):  
Statistical Tests ◽  
Phylogenetic Analyses ◽  
Nuclear Data ◽  
Reticulate Evolution ◽  
Hybrid Origin ◽  
Closely Related Species ◽  
New Mexican ◽  
Molecular Phylogenetic ◽  
Present Distribution ◽  
Selection Of

The frequency and relative importance of hybridization in plants has been an area of intense debate. Although this evolutionary phenomenon has received considerable attention from plant biologists, there are no well-supported cases of reticulate evolution involving parasitic plants, to date. Recent molecular phylogenetic analyses revealed that the subgenus Grammica , the largest and most diverse group of the stem-parasitic genus Cuscuta (dodder), consists of 15 major clades. We describe here five cases of strongly supported discordance between phylogenies derived from plastid and nuclear data, and interpret them as results of five independent hybridization events. Three of these cases could represent relatively recent reticulations, as each of them involves more closely related species, always confined within the same major clade as their putative parental species, and are currently sympatric or parapatric with them. The two remaining cases involve species whose potential progenitors are derived from different major groups of Grammica, and which are allopatric in their present distribution. A series of statistical tests was conducted to assess and further explore the significance of this phylogenetic incongruence. Alternative explanations for discordant gene topologies are explored. Cuscuta liliputana sp. nov., a new Mexican species of hybrid origin is described.

A study of molecular sequences, sexuality, and morphological variation in Plagiomnium carolinianum, P. maximoviczii, and P. rhynchophorum (Bryophyta, Mniaceae)

Phytotaxa ◽  
2018 ◽  
Vol 375 (1) ◽  
pp. 81
Author(s):  
YAN-JUN YI ◽  
ZHEN-WEI SUN ◽  
SI HE ◽  
MAMTIMIN SULAYMAN
Keyword(s):  
Phylogenetic Analyses ◽  
Single Species ◽  
Molecular Study ◽  
Geographic Range ◽  
Similar Species ◽  
Monophyletic Clade ◽  
Closely Related Species ◽  
Molecular Phylogenetic ◽  
Different Populations ◽  
Rps4 Gene

Morphologically, recognition of the genus Plagiomnium may be relatively easy. Yet identifications of closely related species have met great difficulties. The contemporary species delimitations of P. carolinianum, P. maximoviczii, and P. rhynchophorum largely based on sexuality as the sole distinction have not been satisfactory. As shown from literature, character variations among these three taxa were continuous and intergraded within or among different populations throughout a wide geographic range. No gametophytic characters could be reliably used to distinguish them from each other. Molecular phylogenetic analyses using ITS2 and rps4 gene were undertaken to resolve delineations for these three morphologically similar species. The results suggest that they form a well support monophyletic clade, which can be defined as representing one single species with two subspecies, i.e. P. rhynchophorum subsp. maximoviczii and P. rhynchophorum subsp. rhynchophorum. The present molecular study supports the treatment of P. carolinianum as synonym of P. rhynchophorum as purposed previously by Koponen based on morphology.

High genetic diversity, distant phylogenetic relationships and intraspecies recombination events among natural populations of Yam mosaic virus: a contribution to understanding potyvirus evolution

Microbiology ◽  
2000 ◽  
Vol 81 (1) ◽  
pp. 243-255 ◽  
Author(s):  
M. Bousalem ◽  
E. J. P. Douzery ◽  
D. Fargette
Keyword(s):  
Genetic Diversity ◽  
Mosaic Virus ◽  
Statistical Tests ◽  
Phylogenetic Analyses ◽  
Natural Populations ◽  
High Genetic Diversity ◽  
Single Clade ◽  
Cultivated Species ◽  
Selection Of

To evaluate the genetic diversity and understand the evolution of Yam mosaic virus (YMV), a highly destructive pathogen of yam (Dioscorea sp.), sequencing was carried out of the C-terminal part of the replicase (NIb), the coat protein (CP) and the 3′-untranslated region (3′-UTR) of 27 YMV isolates collected from the three main cultivated species (Dioscorea alata, the complex Dioscorea cayenensis–Dioscorea rotundata and Dioscorea trifida). YMV showed the most variable CP relative to eight other potyviruses. This high variability was structured into nine distant molecular groups, as revealed by phylogenetic analyses and validated by assessment of the molecular evolutionary noise. No correlation was observed between the CP and 3′-UTR diversities and phylogenies. The most diversified and divergent groups included isolates from Africa. The remaining groups clustered in a single clade and a geographical distinction between isolates from the Caribbean, South America and Africa was observed. The role of the host in the selection of particular isolates was illustrated by the case of a divergent cultivar from Burkina Faso. Phylogenetic topological incongruence and complementary statistical tests highlighted the fact that recombination events, with single and multiple crossover sites, largely contributed to the evolution of YMV. We hypothesise an African origin of YMV from the yam complex D. cayenensis–D. rotundata, followed by independent transfers to D. alata and D. trifida during virus evolution.

Nomenclatural notes on Laeliinae-V. New combinations for invalid names in Prosthechea (Orchidaceae)

Phytotaxa ◽  
2015 ◽  
Vol 239 (3) ◽  
pp. 297
Author(s):  
Cássio Van den Berg
Keyword(s):  
Central America ◽  
Phylogenetic Analyses ◽  
Nuclear Data ◽  
New Combinations ◽  
Extensive Discussion ◽  
The Third ◽  
Brazilian Species ◽  
Two Systems ◽  
Molecular Phylogenetic ◽  
Mexican Species

Prosthechea Knowles & Westcott (1838: 111) is the third largest genus of Laeliinae Bentham (1881: 287) with 117 species (Chase et al. 2015). The group of species corresponding to Prosthechea is widespread in the Neotropics, especially in Mexico, Central America and Brazil, and has been treated since the 60’s as distinct from Epidendrum Linnaeus (1763: 1347) but with contradictory generic placement. For example, Dressler & Pollard (1971, 1976) included most species in Encyclia subgenus Osmophytum (Lindley 1841: 81) Dressler & Pollard (1971: 433), but dealt only with Mexican species. Pabst & Dungs (1975, 1977) followed Dressler and treated the Brazilian species also in Encyclia Hooker (1828: t. 2831). Brieger (1960) considered them part of Hormidium (Lindley 1841: 81) Heynhold (1841: 880) and later Pabst et al. (1981) transferred most Brazilian species to Anacheilium Hoffmannsegg (1842: 229). Molecular phylogenetic analyses of plastid and nuclear data confirmed that the whole group was monophyletic (van den Berg et al. 2000, 2009, Higgins et al., 2003). After an extensive discussion on the generic names by Higgins (1997), he established that the oldest name for the whole clade was Prosthechea and proposed most of the new combinations for species previously included in Epidendrum, Encyclia, Anacheilium and Hormidium. Later on, other authors decided to subdivide the group into several segregate genera, and proposed two systems that are themselves conflicting in generic circumscription (Withner & Harding 2004, Chiron & Castro Neto 2003a).

scholarly journals Molecular phylogenetic analysis of the north-temperate Labrador Teas (Ericaceae: Rhododendron Subsect. Ledum) suggests a complex genetic history

2017 ◽  
Vol 11 (1) ◽  
pp. 53-65
Author(s):  
Andrew Hart ◽  
Kathleen Kron ◽  
Emily Gillespie
Keyword(s):  
Evolutionary History ◽  
Sequence Data ◽  
Nuclear Data ◽  
Morphological Characters ◽  
Hybrid Origin ◽  
The North ◽  
Biogeographic History ◽  
Molecular Phylogenetic ◽  
Vegetative Characters ◽  
Floral Characters

The Labrador teas are a group of nearly circumboreal shrubs or sub-shrubs inhabiting damp habitats. The 4–7 currently recognized species are classified within Rhododendron subg. Rhododendron section Rhododendron subsect. Ledum. In floral characters, these species are extremely similar. In vegetative characters, species limits in the Labrador teas have been difficult to determine because many of the traditionally used morphological characters vary continually across the geographic range. This study investigated evolutionary history and preliminary consideration of some species boundaries in the Labrador teas using DNA sequence data from five molecular markers to generate a preliminary phylogeny of R. subsect. Ledum. Data were analyzed using Maximum Parsimony, Maximum Likelihood and Bayesian methods. The nuclear data indicate a monophyletic subsect. Ledum, but chloroplast data indicate that the North American taxa have an evolutionary history separate from the European and Asian taxa, suggesting that one or both lineages of subsect. Ledum may be of hybrid origin. Additionally, our analyses suggest that taxa combined in recent treatments (i.e. Rhododendron tomentosum) represent separate lineages and should be recognized as distinct instead of included within more broadly defined species, however our current level of sampling cannot completely resolve this issue. This study lays the groundwork for future phylogenetic studies within subsect. Ledum, illustrating the need to sample more intensively across taxa in order to capture what appears to be a complex genetic and biogeographic history.

Validation of Hymenasplenium laterepens (Aspleniaceae): evidence from morphology and molecular analyses

Phytotaxa ◽  
2018 ◽  
Vol 374 (4) ◽  
pp. 277
Author(s):  
YANFEN CHANG ◽  
KIYOTAKA HORI ◽  
NORIAKI MURAKAMI ◽  
LIMIN CAO ◽  
SHUGANG LU ◽  
...  
Keyword(s):  
Related Species ◽  
Yunnan Province ◽  
Phylogenetic Analyses ◽  
Reticulate Evolution ◽  
Morphological Observation ◽  
Molecular Analyses ◽  
Molecular Phylogenetic ◽  
Locus Classicus ◽  
Different Levels ◽  
Meiosis I

The name Hymenasplenium laterepens was first proposed by Cheng and Murakami in 1998 but was not validly published. We recently collected and studied this taxon at its locus classicus in Xishuangbanna, Yunnan Province in China. Molecular phylogenetic analyses and morphological observation of H. laterepens and related species clearly indicate that this is a distinct taxonomic entity worthy of species rank. Phylogenetically, H. laterepens is closely related to H. apogamum and may be involved in the reticulate evolution of the H. apogamum complex, which is comprised of several taxa with different levels of ploidy. Morphologically, H. laterepens is distinguished by the combination of its triangular laminae, large pinnae with acute apices and deeply serrated margins, and ca. 117 chromosomes at meiosis I and 32 spores in each sporangium. This work provides a complete species description and comparison to related species within the genus Hymenasplenium, particularly to other relatives of the “H. unilaterale” group. Hymenasplenium laterepens is described here with diagnosis and type designation.

Phylogeny and biogeography of the Enhydris clade (Serpentes: Homalopsidae)

Zootaxa ◽  
2010 ◽  
Vol 2452 (1) ◽  
pp. 18 ◽  
Author(s):  
DARYL R. KARNS ◽  
VIMOKSALEHI LUKOSCHEK ◽  
JENNIFER OSTERHAGE ◽  
JOHN C. MURPHY ◽  
HAROLD K. VORIS
Keyword(s):  
Southeast Asia ◽  
Southern China ◽  
Phylogenetic Analyses ◽  
Nuclear Gene ◽  
Sensu Stricto ◽  
Substantial Portion ◽  
Closely Related Species ◽  
Molecular Phylogenetic ◽  
Phylogenetic Hypotheses ◽  
Water Snakes

Previous molecular phylogenetic hypotheses for the Homalopsidae, the Oriental-Australian Rear-fanged Water Snakes indicate that Enhydris, the most speciose genus in the Homalopsidae (22 of 37 species), is polyphyletic and may consist of five separate lineages. We expand on earlier phylogenetic hypotheses using three mitochondrial fragments and one nuclear gene, previously shown to be rapidly evolving in snakes, to determine relationships among six closely related species: Enhydris enhydris, E. subtaeniata, E. chinensis, E. innominata, E. jagorii, and E. longicauda. Four of these species (E. subtaeniata, E. innominata, E. jagorii, and E. longicauda) are restricted to river basins in Indochina, while E. chinensis is found in southern China and E. enhydris is widely distributed from India across Southeast Asia. Our phylogenetic analyses indicate that these species are monophyletic and we recognize this clade as the Enhydris clade sensu stricto for nomenclatural reasons. Our analysis shows that E. chinensis is sister-species to a well-supported clade comprising the remaining species of the Enhydris clade (mean p distance between E. chinensis and other in-group taxa was 13.1%, range: 12.7-13.4%). Enhydris innominata, E. longicauda and E. jagorii also formed a strongly supported clade with very low interspecific p distances (mean 0.28%, range: 0–0.46%). We were unable to resolve relationships between E. enhydris and E. subtaeniata (mean divergence of 9.4%, range: 9.2-9.7%), and between these two species and E. innominata, E. longicauda and E. jagorii. We summarize classical morphological (scalation and coloration) characteristics of these species in the context of the molecular phylogeny. The Enhydris clade comprises a substantial portion of the vertebrate biomass of Southeast Asia and we discuss aspects of its biogeography, morphology and systematics.

scholarly journals Ophiocordyceps aphrophoridarum sp. nov., a new entomopathogenic species from Guizhou, China

2021 ◽  
Vol 9 ◽  
Author(s):  
Yu Yang ◽  
Yuanpin Xiao ◽  
Gangjiang Yu ◽  
TingChi Wen ◽  
ChunYing Deng ◽  
...  
Keyword(s):  
New Species ◽  
Entomopathogenic Fungi ◽  
Related Species ◽  
Phylogenetic Analyses ◽  
Closely Related Species ◽  
Important Species ◽  
Wide Range ◽  
The Family ◽  
Molecular Phylogenetic ◽  
A New Species

Ophiocordyceps is the largest genus in the family Ophiocordicipitaceae, including many entomopathogenic species. In recent years, many species have been described in this genus, with a wide range of host insects. Entomopathogenic fungi include ecologically, economically and medicinally important species, but a large portion of their diversity remains to be discovered and described. In this study, a new species, Ophiocordyceps aphrophoridarum sp. nov, parasitising Aphrophoridae sp. (Hemiptera) is proposed from China, based on evidence from morphology and molecular phylogenetic analyses. This species is characterised by fibrous, pigmented stromata, cylindrical asci and filiform ascospores. Compared to its closest relative, O. tricentri, the new species has wider perithecia and longer asci. Molecular phylogenetic analyses of a multilocus dataset (consisting of SSU, ITS, LSU, TEF1, RPB1 and RPB2) confirm its placement in Ophiocordyceps. Ophiocordyceps aphrophoridarum is morphologically described and illustrated with colour photographs. Morphological comparisons with closely-related species are also presented in tabulated format.

scholarly journals A new species of the genus Rana sensu lato Linnaeus, 1758 (Anura, Ranidae) from Wuyi Mountain, Fujian Province, China

ZooKeys ◽  
2021 ◽  
Vol 1065 ◽  
pp. 101-124
Author(s):  
Yanqing Wu ◽  
Shengchao Shi ◽  
Huiguang Zhang ◽  
Weicai Chen ◽  
Bin Cai ◽  
...  
Keyword(s):  
New Species ◽  
Body Size ◽  
Phylogenetic Analyses ◽  
Dorsal Surface ◽  
Adult Males ◽  
Fujian Province ◽  
Closely Related Species ◽  
Adult Females ◽  
Molecular Phylogenetic ◽  
A New Species

A new species of the frog genus Rana sensu lato from Wuyi Mountain, Fujian Province, China is described. Molecular phylogenetic analyses clustered the new species into the R. johnsi group and indicated that it was genetically divergent from its closely related species. The new species could be distinguished from its congeners by a combination of the following characters: body size medium, SVL 41.4–45.6 mm (42.9 ± 1.9 mm, n = 4) in adult males and 47.6–50.3 mm (n = 2) in adult females; adult male with a pair of internal subgular vocal sacs; lateroventral grooves present on tip of toes; webbing on fourth toes reaching the tip of toe; transverse skin ridges distinctly present on the dorsal surface of thigh and tibia, the number large (mean 26.5 ± 2.7, range 22–29, n = 6); breeding males possess creamy white nuptial pad with tiny velvety spines on the dorsal surface of the first finger, divided into three parts.

scholarly journals Disentangling Reticulate Evolution of North Temperate Haplostemonous Ludwigia (Onagraceae)

2020 ◽  
Vol 105 (2) ◽  
pp. 163-182
Author(s):  
Shih-Hui Liu ◽  
Hsun-An Yang ◽  
Yoshiko Kono ◽  
Peter C. Hoch ◽  
Janet C. Barber ◽  
...  
Keyword(s):  
Phylogenetic Trees ◽  
Diploid Species ◽  
Single Copy ◽  
Reticulate Evolution ◽  
Plant Evolution ◽  
Hybrid Origin ◽  
Ploidy Levels ◽  
The North ◽  
Molecular Phylogenetic ◽  
Ancestral Area Reconstruction

While it is known that whole genome duplication (WGD) and reticulate evolution play important roles in plant evolution, the origins and evolutionary histories of most polyploid and reticulate groups are still poorly known. The North Temperate haplostemonous (NTH) Ludwigia L. (sections Isnardia (L.) W. L. Wagner & Hoch, Ludwigia, Microcarpium Munz, and Miquelia P. H. Raven) group, characterized by having 4-merous and haplostemonous flowers, pluriseriate and free seeds, glabrous and convex nectaries, and a north-temperate distribution, is a polyploid complex (2×, 4×, 6×, and 8×) of 24 species with frequent reports of inter- and intrasectional hybridization. Although earlier biosystematics studies postulated some evolutionary scenarios and recent molecular phylogenetic studies have partially tested these propositions, the full history of their reticulate evolution remains puzzling. In this study, we sequenced four chloroplast regions (rpL16, rpoB-trnC, trnL-trnF, and ycf6-psbM) and conducted extensive molecular cloning of the biparentally inherited single-copy nuclear PgiC gene (376 clones in total), sampling 23 of the 24 NTH Ludwigia species whose chromosome numbers and ploidy levels were confirmed. Both the chloroplast and PgiC trees include strongly supported sister clades of section Ludwigia (four diploid species) and the “Microcarpium complex” (composed of sections Isnardia, Microcarpium, and Miquelia), which together are sister to the rest of Ludwigia. In the PgiC tree, eight clades are identified within the Microcarpium complex, with four clades including no extant diploid species. Neither sections Isnardia nor Microcarpium are monophyletic, while the monospecific section Miquelia has a hybrid origin. By integrating our phylogenetic trees with previous cytological hypotheses, the reticulate evolution of NTH Ludwigia is disentangled and four to eight extinct diploid species are inferred. Ancestral area reconstruction supports a North American origin of L. ovalis whose current East Asian distribution reflects a relict of the Arcto-Tertiary Geoflora. Based on our results, we propose to synonymize sections Microcarpium and Miquelia under the expanded section Isnardia.

Sign in / Sign up

Export Citation Format

Share Document