DNA renaturation kinetics in some paedogenetic urodeles

Morescalchi, A.; Serra, Virginia

doi:10.1007/bf01926308

Cited by 24 publications

(8 citation statements)

References 14 publications

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“…Many different ideas have been proposed to explain genome size variation among organisms. The simplest explanation is a change in the ratio of DNA that codes for proteins versus non-protein coding DNA [ 29 ]. Although variation in gene number maybe important, this distinction is too simple because non-protein coding DNA has been shown in recent years to encode a diversity of functional elements.…”

Section: Discussionmentioning

confidence: 99%

Genic regions of a large salamander genome contain long introns and novel genes

et al. 2009

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Section: Discussionmentioning

confidence: 99%

Genic regions of a large salamander genome contain long introns and novel genes

et al. 2009

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“…The axolotl genome consists of 14 chromosome pairs (2N = 28) 14 and estimates of its physical size range from 21–48 gigabases 15 16 17 . Early DNA reannealing studies suggested that repetitive elements constitute at least 70% of the A. tigrinum genome, a close relative of the axolotl; similarly large repetitive fractions are predicted for other salamander genomes 18 19 20 21 22 . Indeed, large genome size is a common feature of all extant salamanders, suggesting a shared period of genome expansion prior to the basal salamander divergence during the early Jurassic, ~180 million years ago 23 .…”

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confidence: 89%

Initial characterization of the large genome of the salamander Ambystoma mexicanum using shotgun and laser capture chromosome sequencing

Keinath

Timoshevskiy

Timoshevskaya

et al. 2015

Sci Rep

138

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Vertebrates exhibit substantial diversity in genome size, and some of the largest genomes exist in species that uniquely inform diverse areas of basic and biomedical research. For example, the salamander Ambystoma mexicanum (the Mexican axolotl) is a model organism for studies of regeneration, development and genome evolution, yet its genome is ~10× larger than the human genome. As part of a hierarchical approach toward improving genome resources for the species, we generated 600 Gb of shotgun sequence data and developed methods for sequencing individual laser-captured chromosomes. Based on these data, we estimate that the A. mexicanum genome is ~32 Gb. Notably, as much as 19 Gb of the A. mexicanum genome can potentially be considered single copy, which presumably reflects the evolutionary diversification of mobile elements that accumulated during an ancient episode of genome expansion. Chromosome-targeted sequencing permitted the development of assemblies within the constraints of modern computational platforms, allowed us to place 2062 genes on the two smallest A. mexicanum chromosomes and resolves key events in the history of vertebrate genome evolution. Our analyses show that the capture and sequencing of individual chromosomes is likely to provide valuable information for the systematic sequencing, assembly and scaffolding of large genomes.

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“…The remainder of the DNA reassociates slowly with a C0tl/2 value of 1.2 • 104. Triturus c. carni]ex has a DNA content of between 21 pg (Sexsmith, 1968;Morescalchi and Serra, 1974) and 29 pg (quoted by Callan, 1972) per haploid genome, which is equivalent to 2-3 • 101~ nucleotide pairs and a theoretical C0tl/~ for unique sequences, according to Britten and Kohne (1968), in excess of 3.4 • 10 ~. Consequently the experimental C0tl/2 value of 1.2 • 104 for slowly reassociating sequences is lower than the expected value.…”

Section: Reassociation and Molecular Hybridization (A) Reassociation mentioning

confidence: 99%

Transcription of genetic information in amphibian oocytes

Sommerville

Malcolm

1976

Chromosoma

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Abstract. The lampbrush chromosomes of amphibian oocytes are highly active in RS~A transcription. The extent of transcription and features of the transcriptional product have been studied both cytologically and by molecular hybridization. Each lampbrush loop is considered to be a unit of transcription which generates many primary transcript molecules. In Triturus the primary transcripts can be recovered as nuclear RNP particles which can be dispersed in the presence of formamide to give linear forms of up to 20 ~m or more in length. Only part of the RNA extracted from nuclear RNP codes for protein, the remainder containing non-informationM repetitive sequences. Although about 4% of the chromosomal DNA of Triturus is transcribed during oogenesis, only 0.05-0.1% of the DNA is expressed as coding sequences. This informational sequence complexity is equivalent to approximately 10 ~ different mRNA species. A model for the organization of genetic sequences in the lampbrush chromosomes is suggested.

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DNA renaturation kinetics in some paedogenetic urodeles

Cited by 24 publications

References 14 publications

Genic regions of a large salamander genome contain long introns and novel genes

Genic regions of a large salamander genome contain long introns and novel genes

Initial characterization of the large genome of the salamander Ambystoma mexicanum using shotgun and laser capture chromosome sequencing

Transcription of genetic information in amphibian oocytes

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