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Marcus A Koch - One of the best experts on this subject based on the ideXlab platform.
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phylogenetic signatures of adaptation the Arabis hirsuta species aggregate brassicaceae revisited
Perspectives in Plant Ecology Evolution and Systematics, 2014Co-Authors: Robert Karl, Marcus A KochAbstract:The mustard family, Brassicaceae, is well-known for its homoplasy in almost any morphological character at practically all taxonomic levels. The genus Arabis, within the largest tribe of the Brassicaceae, is such an example comprising numerous para- and polyphyletic groups of taxa. Past research during the last 15 years has unraveled many phylogenetic relationships among the ∼550 (or more) species within the notoriously difficult tribe Arabideae. The European Arabis hirsuta species aggregate has remained unexplored, however. Herein we analyze phylogenetic relationships using nuclear ITS and plastid DNA sequences of Eurasian Arabis to characterize Hairy rock cress (A. hirsuta) and its relatives. Representative geographic sampling is used to study character and trait evolution, and bioclimatic data are used to differentiate between species. Our overview puts European Arabis into a reliable evolutionary framework, and we provide some striking insights into evolutionary trends and correlating morphological characters from seeds and flowers with environmental data such as climate variables and elevation. We demonstrate independent parallel evolution of sets of traits, and, therefore, we could further elaborate our previous findings that within tribe Arabideae high speciation rates are correlated with perennial growth form and occurrence at higher elevation. Finally some taxonomical remarks are provided to give added context.
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the importance of anatolian mountains as the cradle of global diversity in Arabis alpina a key arctic alpine species
Annals of Botany, 2011Co-Authors: Stephen W Ansell, Marcus A Koch, Hans K Stenoien, Michael Grundmann, Stephen J Russell, Harald Schneider, Johannes C VogelAbstract:BACKGROUND AND AIMS Anatolia is a biologically diverse, but phylogeographically under-explored region. It is described as either a centre of origin and long-term Pleistocene refugium, or as a centre for genetic amalgamation, fed from distinct neighbouring refugia. These contrasting hypotheses are tested through a global phylogeographic analysis of the arctic-alpine herb, Arabis alpina. METHODS Herbarium and field collections were used to sample comprehensively the entire global range, with special focus on Anatolia and Levant. Sequence variation in the chloroplast DNA trnL-trnF region was examined in 483 accessions. A haplotype genealogy was constructed and phylogeographic methods, demographic analysis and divergence time estimations were used to identify the centres of diversity and to infer colonization history. KEY RESULTS Fifty-seven haplotypes were recovered, belonging to three haplogroups with non-overlapping distributions in (1) North America/Europe/northern Africa, (2) the Caucuses/Iranian Plateau/Arabian Peninsula and (3) Ethiopia-eastern Africa. All haplogroups occur within Anatolia, and all intermediate haplotypes linking the three haplogroups are endemic to central Anatolia and Levant, where haplotypic and nucleotide diversities exceeded all other regions. The local pattern of haplotype distribution strongly resembles the global pattern, and the haplotypes began to diverge approx. 2·7 Mya, coinciding with the climate cooling of the early Middle Pleistocene. CONCLUSIONS The phylogeographic structure of Arabis alpina is consistent with Anatolia being the cradle of origin for global genetic diversification. The highly structured landscape in combination with the Pleistocene climate fluctuations has created a network of mountain refugia and the accumulation of spatially arranged genotypes. This local Pleistocene population history has subsequently left a genetic imprint at the global scale, through four range expansions from the Anatolian diversity centre into Europe, the Near East, Arabia and Africa. Hence this study also illustrates the importance of sampling and scaling effects when translating global from local diversity patterns during phylogeographic analyses.
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Colonizing the American continent: Systematics of the genus Arabis in North America (Brassicaceae).
American journal of botany, 2010Co-Authors: Marcus A Koch, Robert Karl, Christiane Kiefer, Ihsan A. Al-shehbazAbstract:The circumscription of the genus Arabis underwent many and drastic changes within the past. Using DNA sequence information from the nuclear ribosomal RNA and parts of the plastid genome (trnL-trnLF), as well as a critical evaluation of herbarium material from East Asia and North America, we circumscribe the various Arabis taxa of North America. The American and East Asian Arabis species are closely related and, contrary to what was previously believed, they are not closely related to the Eurasian A. hirsuta. Using cpDNA, we found five North American lineages of Arabis with distinct distribution patterns, of which only the purple/red-flowered lineage consists of proven diploids that evolved directly from East Asian progenitors. All other four lineages evolved via ancient hybridization either on the Asian continent prior to migration to North America or showed significant evidence for hybridization and reticulation while diversifying on the American continent. We also provide the first evidence for the systematic circumscription of East Asian Arabis taxa, which together with the North American taxa, form one clade distantly related to European A. ciliata and Eurasian A. hirsuta. The findings also represent the first record of A. pycnocarpa for the floras of China, Japan, and Russian Far East.
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C OLONIZING THE AMERICAN CONTINENT: S YSTEMATICS OF THE GENUS Arabis IN NORTH AMERICA (BRASSICACEAE) 1
2010Co-Authors: Marcus A Koch, Robert Karl, Christiane Kiefer, Ihsan I. A. Al-shehbazAbstract:The circumscription of the genus Arabis underwent many and drastic changes within the past. Using DNA sequence information from the nuclear ribosomal RNA and parts of the plastid genome ( trn L- trn LF), as well as a critical evaluation of herbarium material from East Asia and North America, we circumscribe the various Arabis taxa of North America. The American and East Asian Arabis species are closely related and, contrary to what was previously believed, they are not closely related to the Eurasian A. hirsuta . Using cpDNA, we found fi ve North American lineages of Arabis with distinct distribution patterns, of which only the purple/red-fl owered lineage consists of proven diploids that evolved directly from East Asian progenitors. All other four lineages evolved via ancient hybridization either on the Asian continent prior to migration to North America or showed signifi cant evidence for hybridization and reticulation while diversifying on the American continent. We also provide the fi rst evidence for the systematic circumscription of East Asian Arabis taxa, which together with the North American taxa, form one clade distantly related to European A. ciliata and Eurasian A. hirsuta . The fi ndings also represent the fi rst record of A. pycnocarpa for the fl oras of China, Japan, and Russian Far East.
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molecular systematics and evolution of arabidopsis and Arabis
Plant Biology, 1999Co-Authors: Marcus A Koch, John G Bishop, Thomas MitchelloldsAbstract:: We provide a phylogenetic analysis of the genera Arabidopsis and Arabis based on nuclear ribosomal DNA sequences. We show that traditional taxonomical concepts within tribe Ara-bideae, which includes these genera, are highly artificial. Arabis and Arabidopsis are paraphyletic and consist of several different independent lineages. The genus Capsella, originally placed in tribe Lepideae, is related to North American Arabis and the Arabidopsis thaliana lineage. Other genera, including East Asian Yin-shania, North American Halimolobus, cosmopolitan Barbarea and Cardamine, and European Aubrieta are positioned among different Arabis lineages. One Arabis species, Arabis pauciflora, is only distantly related to tribe Arabideae. Base chromosome number reduction from n = 8 to n = 5 to 7 occurred several times, suggesting that lower base chromosome numbers than n = 8 are derived in tribe Arabideae. Current knowledge on the evolution and systematics of the genera Arabis and Arabidopsis and relationships within the mustard family are summarized and discussed in the light of convergent evolution and transfer of knowledge from Arabidopsis thaliana as a molecular model plant to other species of the Cruciferae.
Ihsan A. Al-shehbaz - One of the best experts on this subject based on the ideXlab platform.
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Colonizing the American continent: Systematics of the genus Arabis in North America (Brassicaceae).
American journal of botany, 2010Co-Authors: Marcus A Koch, Robert Karl, Christiane Kiefer, Ihsan A. Al-shehbazAbstract:The circumscription of the genus Arabis underwent many and drastic changes within the past. Using DNA sequence information from the nuclear ribosomal RNA and parts of the plastid genome (trnL-trnLF), as well as a critical evaluation of herbarium material from East Asia and North America, we circumscribe the various Arabis taxa of North America. The American and East Asian Arabis species are closely related and, contrary to what was previously believed, they are not closely related to the Eurasian A. hirsuta. Using cpDNA, we found five North American lineages of Arabis with distinct distribution patterns, of which only the purple/red-flowered lineage consists of proven diploids that evolved directly from East Asian progenitors. All other four lineages evolved via ancient hybridization either on the Asian continent prior to migration to North America or showed significant evidence for hybridization and reticulation while diversifying on the American continent. We also provide the first evidence for the systematic circumscription of East Asian Arabis taxa, which together with the North American taxa, form one clade distantly related to European A. ciliata and Eurasian A. hirsuta. The findings also represent the first record of A. pycnocarpa for the floras of China, Japan, and Russian Far East.
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Arabis Elgonensis (Brassicaceae), a New Species from Mount Elgon, Uganda
Harvard Papers in Botany, 2007Co-Authors: Ihsan A. Al-shehbazAbstract:ABSTRACT Arabis elgonensis (Brassicaceae), a new species from Mount Elgon, Uganda, is described and illustrated. Its distinguishing characters from the other species of Arabis are discussed.
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Phylogenetic position of Arabis arenicola and generic limits of Aphragmus and Eutrema (Brassicaceae) based on sequences of nuclear ribosomal DNA
Canadian Journal of Botany, 2006Co-Authors: Suzanne I. Warwicks.i. Warwick, Ihsan A. Al-shehbaz, Connie A. Sauderc.a. SauderAbstract:Sequence data from the nuclear ribosomal internal transcribed spacer (ITS) region of 45 taxa were used to determine the phylogenetic relationship of Arabis arenicola to Arabis , Arabidopsis , Braya , and Eutrema , and that of Eutrema to the purportedly related genera Aphragmus , Lignariella , Neomartinella , Platycraspedum , Taphrospermum , and Thellungiella . Arabis arenicola was originally described as Eutrema in 1830, transferred to Arabis in 1898, and has remained in Arabis to the present, even though it is morphologically more similar to Arabidopsis, Braya, and Eutrema. Sequence data were obtained from representative taxa of Arabis, Arabidopsis, and related Boechera and Catolobus, Braya and Neotorularia, and Eutrema, Aphragmus, Lignariella, Neomartinella, Platycraspedum, Taphrospermum, and Thellungiella. The five Arabis arenicola accessions examined had ITS sequences that were identical to each other and to four Arabidopsis lyrata accessions. In both maximum parsimony and maximum likelihood analyses, Arabis arenicola fell within the Arabidopsis clade and was closely aligned with Arabidopsis lyrata. Two of six purportedly related genera were not closely related to Eutrema. Both analyses placed Lignariella within a separate well-supported clade with Aphragmus, while the other four genera, Neomartinella, Platycraspedum, Taphrospermum, and Thellungiella, fell within a well-supported clade with Eutrema. Morphology and molecular data strongly suggest transferring Arabis arenicola to Arabidopsis, expanding Aphragmus to include Lignariella, and expanding Eutrema to include Neomartinella, Platycraspedum, Taphrospermum, and Thellungiella. New combinations in Arabidopsis and Aphragmus are proposed.
Robert Karl - One of the best experts on this subject based on the ideXlab platform.
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phylogenetic signatures of adaptation the Arabis hirsuta species aggregate brassicaceae revisited
Perspectives in Plant Ecology Evolution and Systematics, 2014Co-Authors: Robert Karl, Marcus A KochAbstract:The mustard family, Brassicaceae, is well-known for its homoplasy in almost any morphological character at practically all taxonomic levels. The genus Arabis, within the largest tribe of the Brassicaceae, is such an example comprising numerous para- and polyphyletic groups of taxa. Past research during the last 15 years has unraveled many phylogenetic relationships among the ∼550 (or more) species within the notoriously difficult tribe Arabideae. The European Arabis hirsuta species aggregate has remained unexplored, however. Herein we analyze phylogenetic relationships using nuclear ITS and plastid DNA sequences of Eurasian Arabis to characterize Hairy rock cress (A. hirsuta) and its relatives. Representative geographic sampling is used to study character and trait evolution, and bioclimatic data are used to differentiate between species. Our overview puts European Arabis into a reliable evolutionary framework, and we provide some striking insights into evolutionary trends and correlating morphological characters from seeds and flowers with environmental data such as climate variables and elevation. We demonstrate independent parallel evolution of sets of traits, and, therefore, we could further elaborate our previous findings that within tribe Arabideae high speciation rates are correlated with perennial growth form and occurrence at higher elevation. Finally some taxonomical remarks are provided to give added context.
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Colonizing the American continent: Systematics of the genus Arabis in North America (Brassicaceae).
American journal of botany, 2010Co-Authors: Marcus A Koch, Robert Karl, Christiane Kiefer, Ihsan A. Al-shehbazAbstract:The circumscription of the genus Arabis underwent many and drastic changes within the past. Using DNA sequence information from the nuclear ribosomal RNA and parts of the plastid genome (trnL-trnLF), as well as a critical evaluation of herbarium material from East Asia and North America, we circumscribe the various Arabis taxa of North America. The American and East Asian Arabis species are closely related and, contrary to what was previously believed, they are not closely related to the Eurasian A. hirsuta. Using cpDNA, we found five North American lineages of Arabis with distinct distribution patterns, of which only the purple/red-flowered lineage consists of proven diploids that evolved directly from East Asian progenitors. All other four lineages evolved via ancient hybridization either on the Asian continent prior to migration to North America or showed significant evidence for hybridization and reticulation while diversifying on the American continent. We also provide the first evidence for the systematic circumscription of East Asian Arabis taxa, which together with the North American taxa, form one clade distantly related to European A. ciliata and Eurasian A. hirsuta. The findings also represent the first record of A. pycnocarpa for the floras of China, Japan, and Russian Far East.
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C OLONIZING THE AMERICAN CONTINENT: S YSTEMATICS OF THE GENUS Arabis IN NORTH AMERICA (BRASSICACEAE) 1
2010Co-Authors: Marcus A Koch, Robert Karl, Christiane Kiefer, Ihsan I. A. Al-shehbazAbstract:The circumscription of the genus Arabis underwent many and drastic changes within the past. Using DNA sequence information from the nuclear ribosomal RNA and parts of the plastid genome ( trn L- trn LF), as well as a critical evaluation of herbarium material from East Asia and North America, we circumscribe the various Arabis taxa of North America. The American and East Asian Arabis species are closely related and, contrary to what was previously believed, they are not closely related to the Eurasian A. hirsuta . Using cpDNA, we found fi ve North American lineages of Arabis with distinct distribution patterns, of which only the purple/red-fl owered lineage consists of proven diploids that evolved directly from East Asian progenitors. All other four lineages evolved via ancient hybridization either on the Asian continent prior to migration to North America or showed signifi cant evidence for hybridization and reticulation while diversifying on the American continent. We also provide the fi rst evidence for the systematic circumscription of East Asian Arabis taxa, which together with the North American taxa, form one clade distantly related to European A. ciliata and Eurasian A. hirsuta . The fi ndings also represent the fi rst record of A. pycnocarpa for the fl oras of China, Japan, and Russian Far East.
Mansour S. Alsaid - One of the best experts on this subject based on the ideXlab platform.
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medicinal plant diversity in the flora of saudi arabia 1 a report on seven plant families
Fitoterapia, 2004Co-Authors: Atiqur M Rahman, Mansour S. Alsaid, Jaber S Mossa, Mohammed A AlyahyaAbstract:A preliminary survey on the medicinal plant diversity in the flora of the Kingdom of Saudi Arabia has been made with seven families: Amaranthaceae, Apocynaceae, Capparidaceae, Euphorbiaceae, Labiatae, Polygonaceae and Solanaceae, as an initial study. These families are represented in the flora with 254 species (i.e. 12% of the total species), and individually with 21, 7, 29, 66, 76, 22 and 33 species, respectively. Of these, 86 species, so far investigated, are medicinal, distributed in these seven families as follows: 7, 5, 12, 20, 23, 7 and 12, respectively. The Labiatae have the highest number (23) of medicinal plants among them while maximum medicinal plant diversity within the family has been observed with the Apocynaceae. An enumeration of these 86 medicinal species is presented with the current nomenclature, Arabic names and medicinal uses. This communication aims at emphasizing the importance of setting up conservation priorities, and sustained development of various medicinal plants of Saudi Arabia.
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Traditional Medicinal Plants of Saudi Arabia
The American Journal of Chinese Medicine, 1993Co-Authors: Mansour S. AlsaidAbstract:The work gives an account of the use of twenty plant species in Saudi traditional medicine and their main chemical constituents. The botanical name, local name or names (in Arabic language), family, mode of administration and voucher herbarium numbers are recorded. Such a study is not only to document the current status of traditional uses of medicinal plants in Saudi Arabia, but also to give awareness of possible new drug resources.
Irma Järvelä - One of the best experts on this subject based on the ideXlab platform.
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The T/G−13915 variant upstream of the lactase gene (LCT) is the founder allele of lactase persistence in an urban Saudi population
Journal of medical genetics, 2007Co-Authors: Faiqa Imtiaz, Erkki Savilahti, A Sarnesto, D Trabzuni, K Al-kahtani, I Kagevi, Mohamed S. Rashed, Brian F. Meyer, Irma JärveläAbstract:Background: The prevalence of lactase persistence is high in Saudi Arabia. Objective: To identify a DNA variant for the lactase persistence/non-persistence trait in adult Arabs in Saudi Arabia. Methods: We sequenced DNA from 432 anonymous neonatal blood donors from five different regions of Saudi Arabia to cover the 400 bp region surrounding the previously identified lactase persistence/non-persistence variant C/T−13910 residing in intron 13 of the MCM6 gene. Results: Two anonymous blood donors carried the C/T−13910 genotype. One variant, T/G −13915, residing 5 bp upstream of the C/T−13910 variant, was present in 332 of 432 (76.9%) of the neonatal samples, compatible with previous prevalence figures of lactase persistence in urban Saudi populations. Determination of disaccharidase activities in 25 intestinal biopsy samples showed a highly significant correlation between lactase activity and the T/G−13915 genotypes (p Conclusion: The T/G−13915 variant is the founder mutation of lactase persistence in an urban Saudi population. The results obtained here have implications for genetic testing of adult-type hypolactasia and to analysis of human evolution, the origin of cattle domestication and migrations of the populations in the Arabian peninsula.
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the t g 13915 variant upstream of the lactase gene lct is the founder allele of lactase persistence in an urban saudi population
Journal of Medical Genetics, 2007Co-Authors: Faiqa Imtiaz, Erkki Savilahti, A Sarnesto, D Trabzuni, I Kagevi, Mohamed S. Rashed, Brian F. Meyer, K Alkahtani, Irma JärveläAbstract:Background: The prevalence of lactase persistence is high in Saudi Arabia. Objective: To identify a DNA variant for the lactase persistence/non-persistence trait in adult Arabs in Saudi Arabia. Methods: We sequenced DNA from 432 anonymous neonatal blood donors from five different regions of Saudi Arabia to cover the 400 bp region surrounding the previously identified lactase persistence/non-persistence variant C/T−13910 residing in intron 13 of the MCM6 gene. Results: Two anonymous blood donors carried the C/T−13910 genotype. One variant, T/G −13915, residing 5 bp upstream of the C/T−13910 variant, was present in 332 of 432 (76.9%) of the neonatal samples, compatible with previous prevalence figures of lactase persistence in urban Saudi populations. Determination of disaccharidase activities in 25 intestinal biopsy samples showed a highly significant correlation between lactase activity and the T/G−13915 genotypes (p Conclusion: The T/G−13915 variant is the founder mutation of lactase persistence in an urban Saudi population. The results obtained here have implications for genetic testing of adult-type hypolactasia and to analysis of human evolution, the origin of cattle domestication and migrations of the populations in the Arabian peninsula.