Platypus Genome Provides Unique Insights into Early Mammalian Evolution and Monotreme Biology

AbstractEgg-laying mammals (monotremes) are the only extant mammalian outgroup to therians (marsupial and eutherian animals) and provide key insights into mammalian evolution1,2. Here we generate and analyse reference genomes of the platypus (Ornithorhynchus anatinus) and echidna (Tachyglossus aculeatus), which represent the only two extant monotreme lineages. The nearly complete platypus genome assembly has anchored almost the entire genome onto chromosomes, markedly improving the genome continuity and gene annotation. Together with our echidna sequence, the genomes of the two species allow us to detect the ancestral and lineage-specific genomic changes that shape both monotreme and mammalian evolution. We provide evidence that the monotreme sex chromosome complex originated from an ancestral chromosome ring configuration. The formation of such a unique chromosome complex may have been facilitated by the unusually extensive interactions between the multi-X and multi-Y chromosomes that are shared by the autosomal homologues in humans. Further comparative genomic analyses unravel marked differences between monotremes and therians in haptoglobin genes, lactation genes and chemosensory receptor genes for smell and taste that underlie the ecological adaptation of monotremes.

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Faculty Opinions recommendation of Nuclear architecture of rod photoreceptor cells adapts to vision in mammalian evolution.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1159146.620862 ◽

2009 ◽

Author(s):

Harald Herrmann

Keyword(s):

Nuclear Architecture ◽

Photoreceptor Cells ◽

Rod Photoreceptor ◽

Mammalian Evolution

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Patterns of mammalian evolution across the Cretaceous-Tertiary boundary

Zoosystematics and Evolution ◽

10.1002/mmnz.4850770204 ◽

2001 ◽

Vol 77 (2) ◽

pp. 175-191 ◽

Cited By ~ 1

Author(s):

William A. Clemens

Keyword(s):

Mammalian Evolution

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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 ◽

10.3390/biology10030238 ◽

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.

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Synteny Conservation and Chromosome Rearrangements During Mammalian Evolution

Genetics ◽

10.1093/genetics/147.1.289 ◽

1997 ◽

Vol 147 (1) ◽

pp. 289-296 ◽

Cited By ~ 2

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.

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