Lend an ear to a classic tale of mammalian evolution

Nature ◽  
2021 ◽  
Vol 590 (7845) ◽  
pp. 224-226
Author(s):  
Simone Hoffmann
Keyword(s):  
Mammalian Evolution

scholarly journals Exaptation of Retroviral Syncytin for Development of Syncytialized Placenta, Its Limited Homology to the SARS-CoV-2 Spike Protein and Arguments against Disturbing Narrative in the Context of COVID-19 Vaccination

Biology ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 238
Author(s):  
Malgorzata Kloc ◽  
Ahmed Uosef ◽  
Jacek Z. Kubiak ◽  
Rafik M. Ghobrial
Keyword(s):  
Cell Membrane ◽  
Host Cell ◽  
Envelope Glycoprotein ◽  
Mammalian Species ◽  
Viral Envelope ◽  
Spike Protein ◽  
Mammalian Evolution ◽  
Trophoblast Cells ◽  
Host Cell Membrane ◽  
Uterine Endometrium

Human placenta formation relies on the interaction between fused trophoblast cells of the embryo with uterine endometrium. The fusion between trophoblast cells, first into cytotrophoblast and then into syncytiotrophoblast, is facilitated by the fusogenic protein syncytin. Syncytin derives from an envelope glycoprotein (ENV) of retroviral origin. In exogenous retroviruses, the envelope glycoproteins coded by env genes allow fusion of the viral envelope with the host cell membrane and entry of the virus into a host cell. During mammalian evolution, the env genes have been repeatedly, and independently, captured by various mammalian species to facilitate the formation of the placenta. Such a shift in the function of a gene, or a trait, for a different purpose during evolution is called an exaptation (co-option). We discuss the structure and origin of the placenta, the fusogenic and non-fusogenic functions of syncytin, and the mechanism of cell fusion. We also comment on an alleged danger of the COVID-19 vaccine based on the presupposed similarity between syncytin and the SARS-CoV-2 spike protein.

Synteny Conservation and Chromosome Rearrangements During Mammalian Evolution

Genetics ◽  
1997 ◽  
Vol 147 (1) ◽  
pp. 289-296 ◽  
Author(s):  
Jason Ehrlich ◽  
David Sankoff ◽  
Joseph H Nadeau
Keyword(s):  
Genome Analysis ◽  
Systematic Errors ◽  
Chromosome Rearrangements ◽  
Mammalian Evolution ◽  
Comparative Genome Analysis ◽  
Reciprocal Translocations ◽  
Comparative Genome ◽  
Strong Selection ◽  
Synteny Conservation

Abstract An important problem in comparative genome analysis has been defining reliable measures of synteny conservation. The published analytical measures of synteny conservation have limitations. Nonindependence of comparisons, conserved and disrupted syntenies that are as yet unidentified, and redundant rearrangements lead to systematic errors that tend to overestimate the degree of conservation. We recently derived methods to estimate the total number of conserved syntenies within the genome, counting both those that have already been described and those that remain to be discovered. With this method, we show that ~65% of the conserved syntenies have already been identified for humans and mice, that rates of synteny disruption vary ~25-fold among mammalian lineages, and that despite strong selection against reciprocal translocations, inter-chromosome rearrangements occurred approximately fourfold more often than inversions and other intra-chromosome rearrangements, at least for lineages leading to humans and mice.

scholarly journals Multiple independent appearances of the cecal appendix in mammalian evolution and an investigation of related ecological and anatomical factors

2013 ◽  
Vol 12 (6) ◽  
pp. 339-354 ◽  
Author(s):  
Heather F. Smith ◽  
William Parker ◽  
Sanet H. Kotzé ◽  
Michel Laurin
Keyword(s):  
Mammalian Evolution

The ‘tree of lice’ hints at mammalian evolution

2011 ◽  
Vol 210 (2807) ◽  
pp. 15
Author(s):  
Michael Marshall
Keyword(s):  
Mammalian Evolution

Mammalian Evolution at the Cellular Level

1987 ◽  
pp. 1-66 ◽  
Author(s):  
Carleton J. Phillips ◽  
Bernard Tandler
Keyword(s):  
Cellular Level ◽  
Mammalian Evolution

scholarly journals Mechanical constraint from growing jaw facilitates mammalian dental diversity

2017 ◽  
Vol 114 (35) ◽  
pp. 9403-9408 ◽  
Author(s):  
Elodie Renvoisé ◽  
Kathryn D. Kavanagh ◽  
Vincent Lazzari ◽  
Teemu J. Häkkinen ◽  
Ritva Rice ◽  
...  
Keyword(s):  
Gene Regulatory Networks ◽  
Regulatory Networks ◽  
Self Regulation ◽  
Specific Aspect ◽  
Body Parts ◽  
Mammalian Evolution ◽  
Lateral Expansion ◽  
Model Species ◽  
Higher Taxa ◽  
Gene Regulatory

Much of the basic information about individual organ development comes from studies using model species. Whereas conservation of gene regulatory networks across higher taxa supports generalizations made from a limited number of species, generality of mechanistic inferences remains to be tested in tissue culture systems. Here, using mammalian tooth explants cultured in isolation, we investigate self-regulation of patterning by comparing developing molars of the mouse, the model species of mammalian research, and the bank vole. A distinct patterning difference between the vole and the mouse molars is the alternate cusp offset present in the vole. Analyses of both species using 3D reconstructions of developing molars and jaws, computational modeling of cusp patterning, and tooth explants cultured with small braces show that correct cusp offset requires constraints on the lateral expansion of the developing tooth. Vole molars cultured without the braces lose their cusp offset, and mouse molars cultured with the braces develop a cusp offset. Our results suggest that cusp offset, which changes frequently in mammalian evolution, is more dependent on the 3D support of the developing jaw than other aspects of tooth shape. This jaw–tooth integration of a specific aspect of the tooth phenotype indicates that organs may outsource specific aspects of their morphology to be regulated by adjacent body parts or organs. Comparative studies of morphologically different species are needed to infer the principles of organogenesis.

scholarly journals An elephant-sized Late Triassic synapsid with erect limbs

Science ◽  
2018 ◽  
Vol 363 (6422) ◽  
pp. 78-80 ◽  
Author(s):  
Tomasz Sulej ◽  
Grzegorz Niedźwiedzki
Keyword(s):  
Body Mass ◽  
Rapid Growth ◽  
Late Triassic ◽  
Mammalian Evolution ◽  
Limb Bones ◽  
Stem Group ◽  
Body Sizes ◽  
Latest Eocene

Here, we describe the dicynodontLisowicia bojani, from the Late Triassic of Poland, a gigantic synapsid with seemingly upright subcursorial limbs that reached an estimated length of more than 4.5 meters, height of 2.6 meters, and body mass of 9 tons.Lisowiciais the youngest undisputed dicynodont and the largest nondinosaurian terrestrial tetrapod from the Triassic. The lack of lines of arrested growth and the highly remodeled cortex of its limb bones suggest permanently rapid growth and recalls that of dinosaurs and mammals. The discovery ofLisowiciaoverturns the established picture of the Triassic megaherbivore radiation as a phenomenon restricted to dinosaurs and shows that stem-group mammals were capable of reaching body sizes that were not attained again in mammalian evolution until the latest Eocene.

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