نتایج جستجو برای: plant systematics

تعداد نتایج: 401676  

Journal: :Evolution: Education and Outreach 2010

2014
Da-Long Guo Xiao-Gai Hou Tian Jia

Tree peony is an important horticultural plant worldwide of great ornamental and medicinal value. Long terminal repeat retrotransposons (LTR-retrotransposons) are the major components of most plant genomes and can substantially impact the genome in many ways. It is therefore crucial to understand their sequence characteristics, genetic distribution and transcriptional activity; however, no info...

2005
Helene de Wet Fanie R. van Heerden Ben-Erik van Wyk

The main alkaloids of Antizoma miersiana and one of two species of the southern African endemic genus Antizoma (Menispermaceae), have been studied for the first time. Eight isoquinoline alkaloids could be positively identified (structural type in brackets): crotsparine (proaporphine); bulbocapnine and dicentrine (aporphine); cissacapine, cycleaneonine, cycleanine, insulanoline and insularine (b...

2013
Wenpan Dong Chao Xu Tao Cheng Kui Lin Shiliang Zhou

Plastid genomes are an invaluable resource for plant biological studies. However, the number of completely sequenced plant plastid genomes is still small compared with the vast number of species. To provide an alternative generalized approach, we designed a set of 138 pairs of universal primers for amplifying (termed "short-range PCR") and sequencing the entire genomes of the angiosperm plastid...

Journal: :Philosophical transactions of the Royal Society of London. Series B, Biological sciences 2008
Richard J Abbott Michael G Ritchie Peter M Hollingsworth

Although approximately 150 years have passed since the publication of On the origin of species by means of natural selection, the definition of what species are and the ways in which species originate remain contentious issues in evolutionary biology. The biological species concept, which defines species as groups of interbreeding natural populations that are reproductively isolated from other ...

2001
Eugene F. Stoermer

The present chaotic state of diatom taxonomy presents both significant difficulties and large opportunities for paleolimnologists. Lack of complete and generally available taxonomic treatises and rapid and substantial changes in nomenclature make it necessary for persons using diatom populations to infer environmental conditions to become more deeply and directly involved in diatom systematics,...

2012
Matt Haber Marc Ereshefsky Joel Velasco Richard Richards Tudor Baetu

The relation between method, concept and theory in science is complicated. I seek to shed light on that relation by considering an instance of it in systematics: The additional challenges phylogeneticists face when reconstructing phylogeny not at a single level, but simultaneously at multiple levels of the hierarchy. How does this complicate the task of phylogenetic inference, and how might it ...

2003
Vladimir Zelevinsky

Standard concepts of nuclear physics explaining the systematics of ground state spins in nuclei by the presence of specific coherent terms in the nucleon-nucleon interaction were put in doubt by the observation that these systematics can be reproduced with high probability by randomly chosen rotationally invariant interactions. We review the recent development in this area, along with new origi...

Journal: :Proceedings. Biological sciences 2002
Davide Pisani Adam M Yates Max C Langer Michael J Benton

One of the ultimate aims of systematics is the reconstruction of the tree of life. This is a huge undertaking that is inhibited by the existence of a computational limit to the inclusiveness of phylogenetic analyses. Supertree methods have been developed to overcome, or at least to go around this problem by combining smaller, partially overlapping cladograms. Here, we present a very inclusive g...

Journal: :Memorias do Instituto Oswaldo Cruz 2000
S F Kerr R Merkelz C Mackinnon

The fossil record and systematics of murid rodents, reservoirs of zoonotic cutaneous leishmaniasis in the Palaearctic, Oriental, African, Nearctic and Neotropical, strongly support a Palaearctic origin of Leishmania. The fossil record and systematics of phlebotomine sand flies reinforce this idea. Interpretations of molecular data that place the origin of Leishmania in the Neotropical are incon...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید