Faculty Opinions recommendation of Analysis of the platypus genome suggests a transposon origin for mammalian imprinting.

The venom of the platypus (Ornithorhynchus anatinus) has been poorly studied to date. The recent publication of the platypus genome heralds a new era for mammalian venom research and is a useful starting tool for functional studies of venom components. We report here the patterns of tissue expression of two venom genes, OvNGF and OvCNP, in order to provide some insight into the functions of the proteins they produce and to pave the way for further functional and pharmacological studies, which may lead to the development of novel therapeutic agents.

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Sex Chromosomes: Platypus Genome Suggests a Recent Origin for the Human X

Current Biology ◽

10.1016/j.cub.2008.05.027 ◽

2008 ◽

Vol 18 (13) ◽

pp. R557-R559 ◽

Cited By ~ 3

Author(s):

Hans Ellegren

Keyword(s):

Sex Chromosomes ◽

Platypus Genome ◽

Recent Origin

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Eggs, embryos and the evolution of imprinting: insights from the platypus genome

Reproduction Fertility and Development ◽

10.1071/rd09092 ◽

2009 ◽

Vol 21 (8) ◽

pp. 935 ◽

Cited By ~ 18

Author(s):

Marilyn B. Renfree ◽

Anthony T. Papenfuss ◽

Geoff Shaw ◽

Andrew J. Pask

Keyword(s):

Genomic Imprinting ◽

Large Scale ◽

Strong Support ◽

Gene Clusters ◽

Host Defence ◽

Long Terminal Repeats ◽

Repeat Elements ◽

Platypus Genome ◽

Dna Elements ◽

Genome Analyses

Genomic imprinting is widespread in eutherian and marsupial mammals. Although there have been many hypotheses to explain why genomic imprinting evolved in mammals, few have examined how it arose. The host defence hypothesis suggests that imprinting evolved from existing mechanisms within the cell that act to silence foreign DNA elements that insert into the genome. However, the changes to the mammalian genome that accompanied the evolution of imprinting have been hard to define due to the absence of large-scale genomic resources from all extant classes. The recent release of the platypus genome sequence has provided the first opportunity to make comparisons between prototherian (monotreme, which show no signs of imprinting) and therian (marsupial and eutherian, which have imprinting) mammals. We compared the distribution of repeat elements known to attract epigenetic silencing across the genome from monotremes and therian mammals, particularly focusing on the orthologous imprinted regions. Our analyses show that the platypus has significantly fewer repeats of certain classes in the regions of the genome that have become imprinted in therian mammals. The accumulation of repeats, especially long-terminal repeats and DNA elements, in therian imprinted genes and gene clusters therefore appears to be coincident with, and may have been a potential driving force in, the development of mammalian genomic imprinting. Comparative platypus genome analyses of orthologous imprinted regions have provided strong support for the host defence hypothesis to explain the origin of imprinting.

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Evidence for an endogenous papillomavirus-like element in the platypus genome

Journal of General Virology ◽

10.1099/vir.0.041483-0 ◽

2012 ◽

Vol 93 (6) ◽

pp. 1362-1366 ◽

Cited By ~ 4

Author(s):

Jie Cui ◽

Edward C. Holmes

Keyword(s):

Data Mining ◽

Human Health ◽

Genetic Types ◽

Ornithorhynchus Anatinus ◽

Wide Range ◽

Platypus Genome

Papillomaviruses (PVs) infect a wide range of vertebrates and have diversified into multiple genetic types, some of which have serious consequences for human health. Although PVs have to date only been characterized as exogenous viral forms, here we report the observation of an endogenous viral element (EPVLoa) in the genome of the platypus (Ornithorhynchus anatinus) that is related to PVs. Further data mining for endogenous PV-like elements is therefore warranted.

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The Platypus Genome Unraveled

Cell ◽

10.1016/j.cell.2008.05.038 ◽

2008 ◽

Vol 133 (6) ◽

pp. 953-955 ◽

Cited By ~ 8

Author(s):

Stephen J. O'Brien

Keyword(s):

Platypus Genome

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Conservation of a vitellogenin gene cluster in oviparous vertebrates and identification of its traces in the platypus genome

Gene ◽

10.1016/j.gene.2008.02.001 ◽

2008 ◽

Vol 413 (1-2) ◽

pp. 76-82 ◽

Cited By ~ 43

Author(s):

Patrick J. Babin

Keyword(s):

Gene Cluster ◽

Platypus Genome ◽

Vitellogenin Gene

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Cone visual pigments of monotremes: Filling the phylogenetic gap

Visual Neuroscience ◽

10.1017/s0952523808080255 ◽

2008 ◽

Vol 25 (3) ◽

pp. 257-264 ◽

Cited By ~ 40

Author(s):

MATTHEW J. WAKEFIELD ◽

MARK ANDERSON ◽

ELLEN CHANG ◽

KE-JUN WEI ◽

RAJINDER KAUL ◽

...

Keyword(s):

Visual Pigment ◽

Spectral Properties ◽

Receptor Gene ◽

Sequence Divergence ◽

Duplication Event ◽

Short Wave ◽

Visual Pigments ◽

Genomic Arrangement ◽

Genes Encoding ◽

Platypus Genome

We have determined the sequence and genomic organization of the genes encoding the cone visual pigment of the platypus (Ornithorhynchus anatinus) and the echidna (Tachyglossus aculeatus), and inferred their spectral properties and evolutionary pathways. We prepared platypus and echidna retinal RNA and used primers of the middle-wave-sensitive (MWS), long-wave-sensitive (LWS), and short-wave sensitive (SWS1) pigments corresponding to coding sequences that are highly conserved among mammals; to PCR amplify the corresponding pigment sequences. Amplification from the retinal RNA revealed the expression of LWS pigment mRNA that is homologous in sequence and spectral properties to the primate LWS visual pigments. However, we were unable to amplify the mammalian SWS1 pigment from these two species, indicating this gene was lost prior to the echidna-platypus divergence (∼21 MYA). Subsequently, when the platypus genome sequence became available, we found an LWS pigment gene in a conserved genomic arrangement that resembles the primate pigment, but, surprisingly we found an adjacent (∼20 kb) SWS2 pigment gene within this conserved genomic arrangement. We obtained the same result after sequencing the echidna genes. The encoded SWS2 pigment is predicted to have a wavelength of maximal absorption of about 440 nm, and is paralogous to SWS pigments typically found in reptiles, birds, and fish but not in mammals. This study suggests the locus control region (LCR) has played an important role in the conservation of photo receptor gene arrays and the control of their spatial and temporal expression in the retina in all mammals. In conclusion, a duplication event of an ancestral cone visual pigment gene, followed by sequence divergence and selection gave rise to the LWS and SWS2 visual pigments. So far, the echidna and platypus are the only mammals that share the gene structure of the LWS-SWS2 pigment gene complex with reptiles, birds and fishes.

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Platypus and echidna genomes reveal mammalian biology and evolution

Nature ◽

10.1038/s41586-020-03039-0 ◽

2021 ◽

Author(s):

Yang Zhou ◽

Linda Shearwin-Whyatt ◽

Jing Li ◽

Zhenzhen Song ◽

Takashi Hayakawa ◽

...

Keyword(s):

Sex Chromosome ◽

Gene Annotation ◽

Egg Laying ◽

Comparative Genomic ◽

Mammalian Evolution ◽

Entire Genome ◽

Genomic Changes ◽

Y Chromosomes ◽

Platypus Genome ◽

Unique Chromosome

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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Preliminary genomic survey and sequence analysis of the complement system in non-eutherian mammals

Australian Mammalogy ◽

10.1071/am15036 ◽

2016 ◽

Vol 38 (1) ◽

pp. 80 ◽

Cited By ~ 4

Author(s):

Oselyne T. W. Ong ◽

Lauren J. Young ◽

Julie M. Old

Keyword(s):

Complement System ◽

Membrane Attack Complex ◽

Tammar Wallaby ◽

Monodelphis Domestica ◽

Tasmanian Devil ◽

Complement Components ◽

Phascolarctos Cinereus ◽

Ornithorhynchus Anatinus ◽

Platypus Genome ◽

The Complement System

The complement system is a major mediator of the vertebrate immune system, which functions in both innate and specific immune responses. It comprises more than 30 proteins working to remove foreign cells by way of anaphylatoxins, opsonins or the membrane attack complex. Over the last few years, whole genome sequences of non-eutherian mammals (marsupials and a monotreme), the gray short-tailed opossum (Monodelphis domestica), tammar wallaby (Macropus eugenii), Tasmanian devil (Sarcophilus harrisii), koala (Phascolarctos cinereus) and platypus (Ornithorhynchus anatinus), have become publicly available. Using these sequences, we have identified an array of complement components in non-eutherians using online search tools and algorithms. Of 57 complement and complement-related genes investigated, we identified 46 in the gray short-tailed opossum genome, 27 in the tammar wallaby genome, 44 in the Tasmanian devil genome, 47 in the koala genome and 40 in the platypus genome. The results of this study confirm the presence of key complement components in the immune repertoire of non-eutherian mammals and provide a platform for future studies on immune protection in young marsupials.

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