scholarly journals Marsupial chromosome DNA content and genome size assessed from flow karyotypes: invariable low autosomal GC content

2018 ◽  
Vol 5 (8) ◽  
pp. 171539 ◽  
Author(s):  
Fumio Kasai ◽  
Patricia C. M. O'Brien ◽  
Jorge C. Pereira ◽  
Malcolm A. Ferguson-Smith
Keyword(s):  
Genome Size ◽  
Dna Content ◽  
Chromosome Painting ◽  
Gc Content ◽  
Tammar Wallaby ◽  
Individual Chromosome ◽  
Tasmanian Devil ◽  
Marsupial Species ◽  
Cross Species Chromosome Painting ◽  
High Level

Extensive chromosome homologies revealed by cross-species chromosome painting between marsupials have suggested a high level of genome conservation during evolution. Surprisingly, it has been reported that marsupial genome sizes vary by more than 1.2 Gb between species. We have shown previously that individual chromosome sizes and GC content can be measured in flow karyotypes, and have applied this method to compare four marsupial species. Chromosome sizes and GC content were calculated for the grey short-tailed opossum (2 n = 18), tammar wallaby (2 n = 16), Tasmanian devil (2 n = 14) and fat-tailed dunnart (2 n = 14), resulting in genome sizes of 3.41, 3.31, 3.17 and 3.25 Gb, respectively. The findings under the same conditions allow a comparison between the four species, indicating that the genomes of these four species are 1–8% larger than human. We show that marsupial genomes are characterized by a low GC content invariable between autosomes and distinct from the higher GC content of the marsupial × chromosome.

Chromosome evolution in kangaroos (Marsupialia: Macropodidae): Cross species chromosome painting between the tammar wallaby and rock wallaby spp. with the 2n = 22 ancestral macropodid karyotype

Genome ◽  
1999 ◽  
Vol 42 (3) ◽  
pp. 525-530 ◽  
Author(s):  
RJ Waugh O'Neill ◽  
MDB Eldridge ◽  
R Toder ◽  
MA Ferguson-Smith ◽  
P C O'Brien ◽  
...  
Keyword(s):  
Chromosome Painting ◽  
Chromosome Evolution ◽  
Karyotype Evolution ◽  
Tammar Wallaby ◽  
Fusion Process ◽  
Ancestral Karyotype ◽  
Karyotypic Diversity ◽  
Species Groups ◽  
Cross Species Chromosome Painting ◽  
Karyotype Stability

Marsupial mammals show extraordinary karyotype stability, with 2n = 14 considered ancestral. However, macropodid marsupials (kangaroos and wallabies) exhibit a considerable variety of karyotypes, with a hypothesised ancestral karyotype of 2n = 22. Speciation and karyotypic diversity in rock wallabies (Petrogale) is exceptional. We used cross species chromosome painting to examine the chromosome evolution between the tammar wallaby (2n = 16) and three 2n = 22 rock wallaby species groups with the putative ancestral karyotype. Hybridization of chromosome paints prepared from flow sorted chromosomes of the tammar wallaby to Petrogale spp., showed that this ancestral karyotype is largely conserved among 2n = 22 rock wallaby species, and confirmed the identity of ancestral chromosomes which fused to produce the bi-armed chromosomes of the 2n = 16 tammar wallaby. These results illustrate the fission-fusion process of karyotype evolution characteristic of the kangaroo group.

scholarly journals Ancient Viral Integrations in Marsupials: A Potential Antiviral Defence

2021 ◽  
Author(s):  
Emma F Harding ◽  
Alice G Russo ◽  
Grace J H Yan ◽  
Paul D Waters ◽  
Peter A White
Keyword(s):  
Viral Infections ◽  
Active Role ◽  
Tammar Wallaby ◽  
Eutherian Mammal ◽  
Brushtail Possum ◽  
Replicase Gene ◽  
Tasmanian Devil ◽  
Available N ◽  
Marsupial Species ◽  
Australian Marsupial

Abstract Marsupial viruses are understudied compared to their eutherian mammal counterparts, although they may pose severe threats to vulnerable marsupial populations. Genomic viral integrations, termed endogenous viral elements (EVEs) could protect the host from infection. It is widely known past viral infections and EVEs play an active role in antiviral defence in invertebrates and plants. This study aimed to characterise actively transcribed EVEs in Australian marsupial species, because they may play an integral role in cellular defence against viruses. This study screened publicly available RNA sequencing datasets (n=35) and characterised 200 viral transcripts from thirteen Australian marsupial species. Of the 200 transcripts, 188 originated from either Bornaviridae, Filoviridae or Parvoviridae EVEs. The other 12 transcripts were from putative active infections from members of the Herpesviridae and Anelloviridae, and Hepadnaviridae. EVE transcripts (n=188) were mapped to marsupial genomes (where available, n=5/13) to identify the genomic insertion sites. Of the 188 transcripts, 117 mapped to 39 EVEs within the koala, bare-nosed wombat, tammar wallaby, brushtail possum and Tasmanian devil genomes. The remaining eight animals had no available genome (transcripts n=71). Every marsupial have Bornaviridae, Filoviridae and Parvoviridae EVEs, a trend widely observed in eutherian mammals. Whilst eutherian bornavirus EVEs are predominantly nucleoprotein-derived, marsupial bornavirus EVEs demonstrate a surprising replicase gene bias. We predicted these widely distributed EVEs were conserved within marsupials from ancient germline integrations, as many were over 65 million years old. One bornavirus replicase EVE, present in six marsupial genomes, was estimated to be 160 million years old, predating the American-Australian marsupial split. We considered transcription of these EVEs through small non-coding RNA as an ancient viral defence. Consistent with this, in koala small RNA sequence datasets we detected Bornaviridae replicase and Filoviridae nucleoprotein produced piRNA. These were enriched in testis tissue, suggesting they could protect marsupials from vertically transmitted viral integrations.

scholarly journals Marsupial Genome Sequences: Providing Insight into Evolution and Disease

Scientifica ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-22 ◽  
Author(s):  
Janine E. Deakin
Keyword(s):  
Tammar Wallaby ◽  
Tasmanian Devil ◽  
Genome Sequences ◽  
Transmissible Cancer ◽  
Marsupial Species ◽  
Exciting Time ◽  
Near Future ◽  
Answering Questions ◽  
Insight Into ◽  
Genome Projects

Marsupials (metatherians), with their position in vertebrate phylogeny and their unique biological features, have been studied for many years by a dedicated group of researchers, but it has only been since the sequencing of the first marsupial genome that their value has been more widely recognised. We now have genome sequences for three distantly related marsupial species (the grey short-tailed opossum, the tammar wallaby, and Tasmanian devil), with the promise of many more genomes to be sequenced in the near future, making this a particularly exciting time in marsupial genomics. The emergence of a transmissible cancer, which is obliterating the Tasmanian devil population, has increased the importance of obtaining and analysing marsupial genome sequence for understanding such diseases as well as for conservation efforts. In addition, these genome sequences have facilitated studies aimed at answering questions regarding gene and genome evolution and provided insight into the evolution of epigenetic mechanisms. Here I highlight the major advances in our understanding of evolution and disease, facilitated by marsupial genome projects, and speculate on the future contributions to be made by such sequences.

Genome size and base composition of seven Quercus species: inter- and intra-population variation

Genome ◽  
1998 ◽  
Vol 41 (2) ◽  
pp. 162-168 ◽  
Author(s):  
V Zoldos ◽  
D Papes ◽  
S C Brown ◽  
O Panaud ◽  
S Siljak-Yakovlev
Keyword(s):  
Genome Size ◽  
Dna Content ◽  
Base Composition ◽  
Gc Content ◽  
Population Variation ◽  
French Population ◽  
Content Variation ◽  
Quercus Species ◽  
Dna Content Variation ◽  
Two Populations

Seven Quercus species, four deciduous (Q. cerris, Q. petraea, Q. pubescens, andQ. robur) and three evergreen (Q. coccifera, Q. ilex, andQ. suber), were assessed for DNA content. Their genome sizes ranged from 1.88 to 2.00 pg/2C, namely an interspecific DNA content variation of 6%. In addition, the DNA content of several populations of Q. petraea andQ. robur with different geographical origins, French and Croatian, was estimated. DNA content did not vary among four populations of Q. robur, but did differ between two populations of Q. petraea, the French population having a higher 2C DNA value than the Croatian. The genome size of this French population showed important dispersion among 10 measured individuals. This was in accordance with subsequent cytogenetic data that revealed extra chromosomes in some individuals from this population. The percent GC varied little between the species; a GC content of 39.9% is established as typical for oak.Key words: Quercus, flow cytometry, genome size, GC percent, DNA content variations, extra chromosomes.

scholarly journals Genome Size Diversity in Rare, Endangered, and Protected Orchids in Poland

Genes ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 563
Author(s):  
Monika Rewers ◽  
Iwona Jedrzejczyk ◽  
Agnieszka Rewicz ◽  
Anna Jakubska-Busse
Keyword(s):  
Genome Size ◽  
Species Identification ◽  
Dna Content ◽  
Size Estimation ◽  
Orchid Species ◽  
Infraspecific Taxon ◽  
2C Dna Content ◽  
Plant Families ◽  
Liparis Loeselii ◽  
Identification And Characterization

Orchidaceae is one of the largest and the most widespread plant families with many species threatened with extinction. However, only about 1.5% of orchids’ genome sizes have been known so far. The aim of this study was to estimate the genome size of 15 species and one infraspecific taxon of endangered and protected orchids growing wild in Poland to assess their variability and develop additional criterion useful in orchid species identification and characterization. Flow cytometric genome size estimation revealed that investigated orchid species possessed intermediate, large, and very large genomes. The smallest 2C DNA content possessed Liparis loeselii (14.15 pg), while the largest Cypripedium calceolus (82.10 pg). It was confirmed that the genome size is characteristic to the subfamily. Additionally, for four species Epipactis albensis, Ophrys insectifera, Orchis mascula, Orchis militaris and one infraspecific taxon, Epipactis purpurata f. chlorophylla the 2C DNA content has been estimated for the first time. Genome size estimation by flow cytometry proved to be a useful auxiliary method for quick orchid species identification and characterization.

scholarly journals The DNA content of trophozoites and cysts of Giardia lamblia by microdensitometric quantitation of Feulgen staining and examination by laser scanning confocal microscopy.

1994 ◽  
Vol 42 (11) ◽  
pp. 1413-1416 ◽  
Author(s):  
S L Erlandsen ◽  
E M Rasch
Keyword(s):  
Confocal Microscopy ◽  
Genome Size ◽  
Dna Content ◽  
Giardia Lamblia ◽  
Laser Scanning ◽  
Laser Scanning Confocal Microscopy ◽  
Evolutionary Development ◽  
Scanning Confocal Microscopy ◽  
Dividing Cells ◽  
C Value

We investigated direct measurement of the DNA content of the parasitic intestinal flagellate Giardia lamblia through quantitation by Feulgen microspectrophotometry and also by visualization of Feulgen-stained DNA chromosomes within dividing cells by laser scanning confocal microscopy. Individual trophozoites of Giardia (binucleate) contained 0.144 +/- 0.018 pg of DNA/cell or 0.072 pg DNA/nucleus. Giardia lamblia cysts (quadranucleate) contained 0.313 +/- 0.003 pg DNA or 0.078 pg DNA/nucleus. The genome size (C) value per nucleus ranged between 6.5-7.1 x 10(7) BP for trophozoites and cysts, respectively. Confocal microscopic examination of Giardia trophozoites undergoing binary fission revealed five chromosome-like bodies within each nucleus. Further information about genome size and DNA content within different Giardia species may help to clarify the pivotal role of these primitive eukaryotic cells in evolutionary development.

Phylogenomic study of the subfamily Caprinae by cross-species chromosome painting with Chinese muntjac paints

2005 ◽  
Vol 13 (4) ◽  
pp. 389-399 ◽  
Author(s):  
Ling Huang ◽  
Wenhui Nie ◽  
Jinhuan Wang ◽  
Weiting Su ◽  
Fengtang Yang
Keyword(s):  
Chromosome Painting ◽  
Cross Species Chromosome Painting ◽  
Phylogenomic Study

scholarly journals Comparative analysis reveals within-population genome size variation in a rotifer is driven by large genomic elements with highly abundant satellite DNA repeat elements

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
C. P. Stelzer ◽  
J. Blommaert ◽  
A. M. Waldvogel ◽  
M. Pichler ◽  
B. Hecox-Lea ◽  
...  
Keyword(s):  
Genome Size ◽  
Satellite Dna ◽  
Gc Content ◽  
Size Variation ◽  
Isolated Populations ◽  
Genome Size Variation ◽  
Variable Regions ◽  
Geographic Population ◽  
Genome Size Evolution ◽  
Size Evolution

Abstract Background Eukaryotic genomes are known to display an enormous variation in size, but the evolutionary causes of this phenomenon are still poorly understood. To obtain mechanistic insights into such variation, previous studies have often employed comparative genomics approaches involving closely related species or geographically isolated populations within a species. Genome comparisons among individuals of the same population remained so far understudied—despite their great potential in providing a microevolutionary perspective to genome size evolution. The rotifer Brachionus asplanchnoidis represents one of the most extreme cases of within-population genome size variation among eukaryotes, displaying almost twofold variation within a geographic population. Results Here, we used a whole-genome sequencing approach to identify the underlying DNA sequence differences by assembling a high-quality reference genome draft for one individual of the population and aligning short reads of 15 individuals from the same geographic population including the reference individual. We identified several large, contiguous copy number variable regions (CNVs), up to megabases in size, which exhibited striking coverage differences among individuals, and whose coverage overall scaled with genome size. CNVs were of remarkably low complexity, being mainly composed of tandemly repeated satellite DNA with only a few interspersed genes or other sequences, and were characterized by a significantly elevated GC-content. CNV patterns in offspring of two parents with divergent genome size and CNV patterns in several individuals from an inbred line differing in genome size demonstrated inheritance and accumulation of CNVs across generations. Conclusions By identifying the exact genomic elements that cause within-population genome size variation, our study paves the way for studying genome size evolution in contemporary populations rather than inferring patterns and processes a posteriori from species comparisons.

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