Acanthaceae has received considerable taxonomic attention at the familial, subfamilial, tribal and subtribal levels. Several different infra-familial classifications have been proposed for the Acanthaceae, but no taxo...Acanthaceae has received considerable taxonomic attention at the familial, subfamilial, tribal and subtribal levels. Several different infra-familial classifications have been proposed for the Acanthaceae, but no taxonomic consensus has yet been reached. The main objective of the present study is to throw light on the phenetic relationships and to explore the contribution of morphological and molecular characters in systematics of Acanthaceae. The morphological data viz. macromorphology, stomatography, lamina architecture and ISSR profiles of 30 Egyptian acanthaceous taxa were investigated. The phenetic analysis using NTSYS-PC version 2.02 software based on 55 potentially informative morphological and molecular characters indicated that the used morphological and ISSR criteria is likely to be useful and valuable taxonomic traits. The morphological characters and ISSR aspects of all the studied species produced a phenogram that showed two series;one of them had two subseries, the first one comprised only three taxa while the second divided into two clusters, each contained two groups. The delimitation and the membership of the studied taxa clearly merit additional study using more criteria. The phenetic analysis of both morphological and molecular attributes clarified the segregation of genus Avicennia as a distinct identity away from Acanthaceae. Acanthus mollis & A. montanus are isolated in its own series that comparable to tribe Acantheae of the current taxonomic systems. The studied species of Thunbergia are gathered its own subseries that comparable to tribe Thunbergiae and Ruellia in its own group that comparable to tribe Ruellieae.展开更多
Cladistics is a biological philosophy that uses genealogi-cal relationship among species and an inferred sequence of divergence as the basis of classifi cation.This review critically surveys the chronological developm...Cladistics is a biological philosophy that uses genealogi-cal relationship among species and an inferred sequence of divergence as the basis of classifi cation.This review critically surveys the chronological development of bio-logical classification from Aristotle through our post-genomic era with a central focus on cladistics.In 1957,Julian Huxley coined cladogenesis to denote splitting from subspeciation.In 1960,the English translation of Willi Hennig’s 1950 work,Systematic Phylogenetics,was published,which received strong opposition from phenet-icists,such as numerical taxonomists Peter Sneath and Robert Sokal,and evolutionary taxonomist,Ernst Mayr,and sparked acrimonious debates in 1960-1980.In 1977-1990,Carl Woese pioneered in using small subunit rRNA gene sequences to delimitate the three domains of cellu-lar life and established major prokaryotic phyla.Cladistics has since dominated taxonomy.Despite being compatible with modern microbiological observations,i.e.organisms with unusual phenotypes,restricted expression of charac-teristics and occasionally being uncultivable,increasing recognition of pervasiveness and abundance of horizon-tal gene transfer has challenged relevance and validity of cladistics.The mosaic nature of eukaryotic and prokary-otic genomes was also gradually discovered.In the mid-2000s,high-throughput and whole-genome sequencing became routine and complex geneologies of organisms have led to the proposal of a reticulated web of life.While genomics only indirectly leads to understanding of func-tional adaptations to ecological niches,computational modeling of entire organisms is underway and the gap between genomics and phenetics may soon be bridged.Controversies are not expected to settle as taxonomic classifi cations shall remain subjective to serve the human scientist,not the classifi ed.展开更多
文摘Acanthaceae has received considerable taxonomic attention at the familial, subfamilial, tribal and subtribal levels. Several different infra-familial classifications have been proposed for the Acanthaceae, but no taxonomic consensus has yet been reached. The main objective of the present study is to throw light on the phenetic relationships and to explore the contribution of morphological and molecular characters in systematics of Acanthaceae. The morphological data viz. macromorphology, stomatography, lamina architecture and ISSR profiles of 30 Egyptian acanthaceous taxa were investigated. The phenetic analysis using NTSYS-PC version 2.02 software based on 55 potentially informative morphological and molecular characters indicated that the used morphological and ISSR criteria is likely to be useful and valuable taxonomic traits. The morphological characters and ISSR aspects of all the studied species produced a phenogram that showed two series;one of them had two subseries, the first one comprised only three taxa while the second divided into two clusters, each contained two groups. The delimitation and the membership of the studied taxa clearly merit additional study using more criteria. The phenetic analysis of both morphological and molecular attributes clarified the segregation of genus Avicennia as a distinct identity away from Acanthaceae. Acanthus mollis & A. montanus are isolated in its own series that comparable to tribe Acantheae of the current taxonomic systems. The studied species of Thunbergia are gathered its own subseries that comparable to tribe Thunbergiae and Ruellia in its own group that comparable to tribe Ruellieae.
文摘Cladistics is a biological philosophy that uses genealogi-cal relationship among species and an inferred sequence of divergence as the basis of classifi cation.This review critically surveys the chronological development of bio-logical classification from Aristotle through our post-genomic era with a central focus on cladistics.In 1957,Julian Huxley coined cladogenesis to denote splitting from subspeciation.In 1960,the English translation of Willi Hennig’s 1950 work,Systematic Phylogenetics,was published,which received strong opposition from phenet-icists,such as numerical taxonomists Peter Sneath and Robert Sokal,and evolutionary taxonomist,Ernst Mayr,and sparked acrimonious debates in 1960-1980.In 1977-1990,Carl Woese pioneered in using small subunit rRNA gene sequences to delimitate the three domains of cellu-lar life and established major prokaryotic phyla.Cladistics has since dominated taxonomy.Despite being compatible with modern microbiological observations,i.e.organisms with unusual phenotypes,restricted expression of charac-teristics and occasionally being uncultivable,increasing recognition of pervasiveness and abundance of horizon-tal gene transfer has challenged relevance and validity of cladistics.The mosaic nature of eukaryotic and prokary-otic genomes was also gradually discovered.In the mid-2000s,high-throughput and whole-genome sequencing became routine and complex geneologies of organisms have led to the proposal of a reticulated web of life.While genomics only indirectly leads to understanding of func-tional adaptations to ecological niches,computational modeling of entire organisms is underway and the gap between genomics and phenetics may soon be bridged.Controversies are not expected to settle as taxonomic classifi cations shall remain subjective to serve the human scientist,not the classifi ed.
