The Conserved Marsupial Karyotype: Chromosome Painting and Evolution

Rens, Willem; Ferguson‐Smith, Malcolm A.

doi:10.1007/978-90-481-9023-2_2

Cited by 6 publications

(9 citation statements)

References 36 publications

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“…1 ), indicating that they are more similar to marsupial cathelicidins than to those of monotremes or eutherians. Saha-CATH1 and 2 cluster with opossum and tammar wallaby cathelicidins, suggesting that these genes arose prior to the divergence of these species around 70 million years ago 30 . In comparison, Saha-CATH3, 5 and 6 form a species-specific clade, which suggests that they have arisen through more recent gene duplications.…”

Section: Resultsmentioning

confidence: 99%

“…This hypothesis is supported by phylogenetic analysis which shows that Saha-CATH1 and 2 cluster with other tammar wallaby and opossum cathelicidins, in a sister clade to platypus cathelicidins. As these genes have been conserved for over 70 million years of evolution 30 , they must have an essential function in the marsupial and monotreme immune systems. In eutherians, cathelicidins interact with immune cells to activate, suppress and/or enhance the immune system 1 .…”

Section: Discussionmentioning

confidence: 99%

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Cathelicidins in the Tasmanian devil (Sarcophilus harrisii)

Peel

Cheng

Djordjevic

et al. 2016

Sci Rep

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Tasmanian devil joeys, like other marsupials, are born at a very early stage of development, prior to the development of their adaptive immune system, yet survive in a pathogen-laden pouch and burrow. Antimicrobial peptides, called cathelicidins, which provide innate immune protection during early life, are expressed in the pouch lining, skin and milk of devil dams. These peptides are active against pathogens identified in the pouch microbiome. Of the six characterised cathelicidins, Saha-CATH5 and 6 have broad-spectrum antibacterial activity and are capable of killing problematic human pathogens including methicillin-resistant S. aureus and vancomycin-resistant E. faecalis, while Saha-CATH3 is active against fungi. Saha-CATH5 and 6 were toxic to human A549 cells at 500 μg/mL, which is over seven times the concentration required to kill pathogens. The remaining devil cathelicidins were not active against tested bacterial or fungal strains, but are widely expressed throughout the body, such as in immune tissues, in digestive, respiratory and reproductive tracts, and in the milk and pouch, which indicates that they are likely also important components of the devil immune system. Our results suggest cathelicidins play a role in protecting naive young during pouch life by passive immune transfer in the milk and may modulate pouch microbe populations to reduce potential pathogens.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Cathelicidins in the Tasmanian devil (Sarcophilus harrisii)

Peel

Cheng

Djordjevic

et al. 2016

Sci Rep

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“…Examination of the conserved segment organisation across 2n = 14 ameridelphian and austradelphian species showed that the 2n = 14 karyotypes observed are virtually identical, apart from a few intrachromosomal rearrangements [Rens and Ferguson Smith, 2010]. However, the arrangement of these 19 conserved segments differed markedly in 2n = 22 American and Australian species.…”

Section: Reconstruction Of the Ancestral Marsupial Karyotype From Cromentioning

confidence: 98%

“…When these data were combined with G-banding data on many more species, it was possible to determine the chromosome rearrangements that have occurred during marsupial evolution and reconstruct the marsupial ancestral karyotype ( fig. 2 ) [Rens and Ferguson-Smith, 2010].…”

Section: Reconstruction Of the Ancestral Marsupial Karyotype From Cromentioning

confidence: 99%

The Evolution of Marsupial and Monotreme Chromosomes

Deakin

Graves

Rens

2012

Cytogenet Genome Res

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Marsupial and monotreme mammals fill an important gap in vertebrate phylogeny between reptile-mammal divergence 310 million years ago (mya) and the eutherian (placental) mammal radiation 105 mya. They possess many unique features including their distinctive chromosomes, which in marsupials are typically very large and well conserved between species. In contrast, monotreme genomes are divided into several large chromosomes and many smaller chromosomes, with a complicated sex chromosome system that forms a translocation chain in male meiosis. The application of molecular cytogenetic techniques has greatly advanced our understanding of the evolution of marsupial chromosomes and allowed the reconstruction of the ancestral marsupial karyotype. Chromosome painting and gene mapping have played a vital role in piecing together the puzzle of monotreme karyotypes, particularly their complicated sex chromosome system. Here, we discuss the significant insight into karyotype evolution afforded by the combination of recently sequenced marsupial and monotreme genomes with cytogenetic analysis, which has provided a greater understanding of the events that have shaped not only marsupial and monotreme genomes, but the genomes of all mammals.

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“…In contrast, a more complex set of rearrangements, including a series of fission and fusion events, are predicted to have led to a higher chromosome number in the ancestral eutherian ( Figure 1 ). Chromosome complements observed amongst marsupials are easily derived from the predicted marsupial ancestral karyotype by various combinations of fissions, fusions, and centromere repositioning [ 17 ].…”

Section: Marsupial Chromosome Evolutionmentioning

confidence: 99%

Chromosome Evolution in Marsupials

Deakin

2018

Genes

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Marsupials typically possess very large, distinctive chromosomes that make them excellent subjects for cytogenetic analysis, and the high level of conservation makes it relatively easy to track chromosome evolution. There are two speciose marsupial families with contrasting rates of karyotypic evolution that could provide insight into the mechanisms driving genome reshuffling and speciation. The family Dasyuridae displays exceptional karyotype conservation with all karyotyped species possessing a 2n = 14 karyotype similar to that predicted for the ancestral marsupial. In contrast, the family Macropodidae has experienced a higher rate of genomic rearrangement and one genus of macropods, the rock-wallabies (Petrogale), has experienced extensive reshuffling. For at least some recently diverged Petrogale species, there is still gene flow despite hybrid fertility issues, making this species group an exceptional model for studying speciation. This review highlights the unique chromosome features of marsupial chromosomes, particularly for these two contrasting families, and the value that a combined cytogenetics, genomics, and epigenomics approach will have for testing models of genome evolution and speciation.

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The Conserved Marsupial Karyotype: Chromosome Painting and Evolution

Cited by 6 publications

References 36 publications

Cathelicidins in the Tasmanian devil (Sarcophilus harrisii)

Cathelicidins in the Tasmanian devil (Sarcophilus harrisii)

The Evolution of Marsupial and Monotreme Chromosomes

Chromosome Evolution in Marsupials

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