scholarly journals Molecular genetics of ecological diversification: Duplication and rapid evolution of toxin genes of the venomous gastropod Conus

1999 ◽  
Vol 96 (12) ◽  
pp. 6820-6823 ◽  
Author(s):  
T. F. Duda ◽  
S. R. Palumbi
Keyword(s):  
Molecular Genetics ◽  
Rapid Evolution ◽  
Ecological Diversification ◽  
Toxin Genes

Diversification in trophic morphology and a mating signal are coupled in the early stages of sympatric divergence in crossbills

2019 ◽  
Author(s):  
Cody K Porter ◽  
Julie W Smith
Keyword(s):  
Rapid Evolution ◽  
Ecological Diversification ◽  
Mating Signals ◽  
Ecological Selection ◽  
Trophic Morphology ◽  
Syllable Repetition ◽  
Rapid Diversification ◽  
Seed Eating ◽  
Song Discrimination ◽  
Mating Signal

Abstract Understanding the mechanisms generating diversity in mating signals is critical to understanding the process of speciation. One mechanism of mating signal diversification occurs when phenotypes that experience divergent ecological selection also affect the production of mating signals, resulting in a coupling between ecological diversification and mating signal diversification. Here, we present evidence that rapid diversification in bill size has resulted in the diversification of some components of song structure in a young adaptive radiation of seed-eating finches (red crossbill, Loxia curvirostra complex). Specifically, we find that larger-billed ecotypes sing songs with lower minimum frequencies, lower syllable repetition rates and greater vocal deviation (i.e. lower performance) than smaller-billed ecotypes for pure tonal syllables. In contrast, bill size was not correlated with maximum frequency or frequency bandwidth, and we found no relationship between bill size and any song parameters in buzzy syllables. Furthermore, we found no evidence for a relationship between the degree of bill size divergence and the potential for song discrimination between sympatric ecotypes. Because bill size is correlated with some features of pure tonal syllables (which appear to be most important for courtship in crossbills) in crossbill song, our results suggest that there was an early-evolving link between ecological and mating signal diversification that may have influenced the rapid evolution of reproductive isolation between sympatric ecotypes.

Introduction

1978 ◽  
Vol 36 (3) ◽  
pp. 543-544
Author(s):  
W. Bernard
Keyword(s):  
Molecular Weight ◽  
Electron Microscope ◽  
Nucleic Acid ◽  
Gene Mapping ◽  
Molecular Genetics ◽  
Cell Biology ◽  
Gene Activity ◽  
Close Connection ◽  
Basic Information ◽  
Simple Systems

In comparison to many other fields of ultrastructural research in Cell Biology, the successful exploration of genes and gene activity with the electron microscope in higher organisms is a late conquest. Nucleic acid molecules of Prokaryotes could be successfully visualized already since the early sixties, thanks to the Kleinschmidt spreading technique - and much basic information was obtained concerning the shape, length, molecular weight of viral, mitochondrial and chloroplast nucleic acid. Later, additonal methods revealed denaturation profiles, distinction between single and double strandedness and the use of heteroduplexes-led to gene mapping of relatively simple systems carried out in close connection with other methods of molecular genetics.

Molecular Genetics Of Acoustic Tumors

1992 ◽  
Vol 25 (5) ◽  
pp. 995-1009
Author(s):  
Michael J. Lanser
Keyword(s):  
Molecular Genetics

The Glissonian Approach of the Hilum

Swiss Surgery ◽  
1999 ◽  
Vol 5 (3) ◽  
pp. 143-146 ◽  
Author(s):  
Launois ◽  
Maddern ◽  
Tay
Keyword(s):  
Portal Vein ◽  
Hepatic Artery ◽  
Posterior Approach ◽  
Hepatic Duct ◽  
Rapid Evolution ◽  
Hepatic Tissue ◽  
Detailed Knowledge ◽  
Porta Hepatis ◽  
Liver Segment ◽  
Glissonian Approach

The detailed knowledge of the segmental anatomy of the liver has led to a rapid evolution in resectional surgery based on the intrahepatic distribution of the portal trinity (the hepatic artery, hepatic duct and portal vein). The classical intrafascial or extrahepatic approach is to isolate the appropriate branch of the portal vein, hepatic artery and the hepatic duct, outside the liver substance. Another method, the extrafascial approach, is to dissect the whole sheath of the pedicle directly after division of a substantial amount of the hepatic tissue to reach the pedicle, which is surrounded by a sheath, derived from Glisson's capsule. This Glissonian sheath encloses the portal trinity. In the transfissural or intrahepatic approach, these sheaths can be approached either anteriorly (after division of the main, right or umbilical fissure) or posteriorly from behind the porta hepatis. We describe the technique for approaching the Glissonian sheath and hence the hepatic pedicle structures and their branches by the intrahepatic posterior approach that allows early delineation of the liver segment without the need for ancillary techniques. In addition, the indications for the use of this technique in the technical and oncologic settings are also discussed.

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