scholarly journals A single origin of extreme matrotrophy in African mabuyine skinks

2016 ◽  
Vol 12 (8) ◽  
pp. 20160430 ◽  
Author(s):  
Margarita Metallinou ◽  
Jeffrey L. Weinell ◽  
Benjamin R. Karin ◽  
Werner Conradie ◽  
Philipp Wagner ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Species Tree ◽  
Single Origin ◽  
Group Ideal ◽  
Phylogenetic Hypotheses

Most mammals and approximately 20% of squamates (lizards and snakes) are viviparous, whereas all crocodilians, birds and turtles are oviparous. Viviparity evolved greater than 100 times in squamates, including multiple times in Mabuyinae (Reptilia: Scincidae), making this group ideal for studying the evolution of nutritional patterns associated with viviparity. Previous studies suggest that extreme matrotrophy, the support of virtually all of embryonic development by maternal nutrients, evolved as many as three times in Mabuyinae: in Neotropical Mabuyinae (63 species), Eumecia (2 species; Africa) and Trachylepis ivensii (Africa). However, no explicit phylogenetic hypotheses exist for understanding the evolution of extreme matrotrophy. Using multilocus DNA data, we inferred a species tree for Mabuyinae that implies that T. ivensii (here assigned to the resurrected genus Lubuya ) is sister to Eumecia , suggesting that extreme matrotrophy evolved only once in African mabuyine skinks.

Gender-bending aubergines: molecular phylogenetics of cryptically dioecious Solanum in Australia

2009 ◽  
Vol 22 (2) ◽  
pp. 107 ◽  
Author(s):  
Christopher T. Martine ◽  
Gregory J. Anderson ◽  
Donald H. Les
Keyword(s):  
Molecular Phylogenetics ◽  
Dioecious Species ◽  
Australian Species ◽  
Single Origin ◽  
Matk Gene ◽  
The Subject ◽  
Phylogenetic Hypotheses ◽  
Past Climate Change ◽  
Ideal Group

The causes, consequences and correlates of dioecy have been the subject of much discussion since the days of Darwin. Several recent authors have stressed the importance of informing this body of theory, with studies focusing on lineages in which both dioecy and hermaphroditism are present. The genus Solanum is an ideal group for analysis, because dioecy, hermaphroditism and potential unisexual transitions (e.g. andromonoecy) among them all occur. Phylogenetic hypotheses are presented for the Australian species in Solanum subgenus Leptostemonum (the ‘spiny solanums’) section Melongena, which contains 10 of the 14 currently described dioecious species in the genus. Phylogenetic analysis of the ITS and trnK–matK gene regions supports a single origin of dioecy from andromonoecy in Australian Solanum. The causes, mechanisms, and maintenance of dioecy in Australian Solanum are explored, including the role of past climate change in the establishment of centres of endemism.

scholarly journals Evolutionary puzzle: discussing the evolution of sentience in Metazoa through a phylogenetic perspective

2021 ◽  
Author(s):  
Michaella Pereira Andrade ◽  
Charles Morphy Dias Santos
Keyword(s):  
Nervous System ◽  
Sensory System ◽  
Sister Group ◽  
Common Ancestry ◽  
Single Origin ◽  
Research Bias ◽  
Phylogenetic Perspective ◽  
The Common ◽  
Phylogenetic Hypotheses ◽  
Subjective States

Sentience is the capacity of organisms to feel and experience through subjective states. During the last years, several investigations have indicated that response mechanisms to harmful stimuli can be highly conserved among the Metazoa. However, there is a research bias towards vertebrates in the available studies. Here we discuss the evolution of the nervous and sensory system, pain and nociception in animals through a phylogenetic perspective testing the hypothesis of common ancestry of sentience. Our results indicate that characteristics related to sentience - morphological and molecular and behavioural -, were already present in the common ancestors of Metazoa, Eumetazoa and Bilateria. Our phylogenetic hypotheses positioned Porifera as the sister-group to all the other Metazoa, corroborating the hypothesis of a single origin of the nervous system. Our results also depict Urbilateria as the ancestor of the metazoan toolkit related to the sentience. These scenarios suggest that some attributes of the sensory system may have appeared even before the emergence of the nervous system, through possible cooptations of sensory modules of the first Metazoa.

Live Confocal Analysis of Fertilization and Early Development

2001 ◽  
Vol 7 (S2) ◽  
pp. 1012-1013
Author(s):  
Uyen Tram ◽  
William Sullivan
Keyword(s):  
Drosophila Melanogaster ◽  
Embryonic Development ◽  
Real Time ◽  
Early Development ◽  
Fluorescent Probes ◽  
Primary Defect ◽  
Fluorescent Analysis ◽  
Dynamic Event ◽  
Enormous Amount ◽  
Fluorescent Studies

Embryonic development is a dynamic event and is best studied in live animals in real time. Much of our knowledge of the early events of embryogenesis, however, comes from immunofluourescent analysis of fixed embryos. While these studies provide an enormous amount of information about the organization of different structures during development, they can give only a static glimpse of a very dynamic event. More recently real-time fluorescent studies of living embryos have become much more routine and have given new insights to how different structures and organelles (chromosomes, centrosomes, cytoskeleton, etc.) are coordinately regulated. This is in large part due to the development of commercially available fluorescent probes, GFP technology, and newly developed sensitive fluorescent microscopes. For example, live confocal fluorescent analysis proved essential in determining the primary defect in mutations that disrupt early nuclear divisions in Drosophila melanogaster. For organisms in which GPF transgenics is not available, fluorescent probes that label DNA, microtubules, and actin are available for microinjection.

ADHD therapy with methylphenidate in mothers – a danger for embryonic development?

2014 ◽  
Vol 47 (06) ◽  
Author(s):  
N Bergemann ◽  
K Boyle ◽  
WE Paulus
Keyword(s):  
Embryonic Development

Darwin's two competing phylogenetic trees: marsupials as ancestors or sister taxa?

2012 ◽  
Vol 39 (2) ◽  
pp. 217-233 ◽  
Author(s):  
J. David Archibald
Keyword(s):  
Fossil Record ◽  
Evolutionary Biology ◽  
Phylogenetic Trees ◽  
Charles Darwin ◽  
The Other ◽  
Charles Lyell ◽  
Single Origin ◽  
Molecular Studies ◽  
Richard Owen ◽  
First Time

Studies of the origin and diversification of major groups of plants and animals are contentious topics in current evolutionary biology. This includes the study of the timing and relationships of the two major clades of extant mammals – marsupials and placentals. Molecular studies concerned with marsupial and placental origin and diversification can be at odds with the fossil record. Such studies are, however, not a recent phenomenon. Over 150 years ago Charles Darwin weighed two alternative views on the origin of marsupials and placentals. Less than a year after the publication of On the origin of species, Darwin outlined these in a letter to Charles Lyell dated 23 September 1860. The letter concluded with two competing phylogenetic diagrams. One showed marsupials as ancestral to both living marsupials and placentals, whereas the other showed a non-marsupial, non-placental as being ancestral to both living marsupials and placentals. These two diagrams are published here for the first time. These are the only such competing phylogenetic diagrams that Darwin is known to have produced. In addition to examining the question of mammalian origins in this letter and in other manuscript notes discussed here, Darwin confronted the broader issue as to whether major groups of animals had a single origin (monophyly) or were the result of “continuous creation” as advocated for some groups by Richard Owen. Charles Lyell had held similar views to those of Owen, but it is clear from correspondence with Darwin that he was beginning to accept the idea of monophyly of major groups.

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