Diploid-Triploid Mosaicism and Tissue Ploidy Diversity within &lt;i&gt;Platemys platycephala&lt;/i&gt; from Suriname

Bickham, John W.; Hanks, Brian G.

doi:10.1159/000297716

Cited by 9 publications

(9 citation statements)

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“…In this tissue, 100% of the cells were triploid in two of the mosaic specimens, 100% diploid in another and some vestigial 2n cells were detected in one sample (less than 1.5%). Some cases confirm that the use of blood is an accurate determinate of overall ploidy levels [19], once the comparison of the proportions of diploid and triploid cells in the blood with the ones determined in other tissues of the same individual, it showed only minor deviation. On the contrary, in our case, if only blood have been analysed, the mosaics would have been misdiagnosed as complete diploid and/or triploid individuals.…”

Section: Discussionmentioning

confidence: 91%

“…The detected frequency of this phenomenon was approximately 10%, indicating that the diploid-triploid mosaics represent a non-regular component of the genetic system of this complex rather than a stably incorporated feature of its reproductive dynamics, as reported in Platemys platycephala [19] and Liolaemus chiliensis [23]. Interestingly, the observed 10% ploidy variation is qualitatively different from previous reports of the same nature such as P. formosa [16] where this frequency was 2 orders of magnitude lower.…”

Section: Discussionmentioning

confidence: 93%

“…On the contrary, in our case, if only blood have been analysed, the mosaics would have been misdiagnosed as complete diploid and/or triploid individuals. The reasons why mosaicism is not present in the S. alburnoides blood samples is difficult to explain, but also in some specimens of the mosaic P. platycephala , blood presented a non-mosaic phenotype while some solid tissues of that same specimens were clearly 2n/3n mixoploid [19]. In one case reported in humans, a 46,XX/69,XXY mosaic also displayed a similar variation between tissues.…”

Section: Discussionmentioning

confidence: 99%

“…Hence, in this context, the S. alburnoides complex is a likely candidate for the occurrence of this phenomenon. Moreover, in some species like Platemys platycephala diploid-triploid mosaics appear to be geographically and population dependent [19]. …”

Section: Introductionmentioning

confidence: 99%

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Ploidy mosaicism and allele-specific gene expression differences in the allopolyploid Squalius alburnoides

et al. 2011

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BackgroundSqualius alburnoides is an Iberian cyprinid fish resulting from an interspecific hybridisation between Squalius pyrenaicus females (P genome) and males of an unknown Anaecypris hispanica-like species (A genome). S. alburnoides is an allopolyploid hybridogenetic complex, which makes it a likely candidate for ploidy mosaicism occurrence, and is also an interesting model to address questions about gene expression regulation and genomic interactions. Indeed, it was previously suggested that in S. alburnoides triploids (PAA composition) silencing of one of the three alleles (mainly of the P allele) occurs. However, not a whole haplome is inactivated but a more or less random inactivation of alleles varying between individuals and even between organs of the same fish was seen.In this work we intended to correlate expression differences between individuals and/or between organs to the occurrence of mosaicism, evaluating if mosaics could explain previous observations and its impact on the assessment of gene expression patterns.ResultsTo achieve our goal, we developed flow cytometry and cell sorting protocols for this system generating more homogenous cellular and transcriptional samples. With this set-up we detected 10% ploidy mosaicism within the S. alburnoides complex, and determined the allelic expression profiles of ubiquitously expressed genes (rpl8; gapdh and β-actin) in cells from liver and kidney of mosaic and non-mosaic individuals coming from different rivers over a wide geographic range.ConclusionsPloidy mosaicism occurs sporadically within the S. alburnoides complex, but in a frequency significantly higher than reported for other organisms. Moreover, we could exclude the influence of this phenomenon on the detection of variable allelic expression profiles of ubiquitously expressed genes (rpl8; gapdh and β-actin) in cells from liver and kidney of triploid individuals. Finally, we determined that the expression patterns previously detected only in a narrow geographic range is not a local restricted phenomenon but is pervasive in rivers where S. pyrenaicus is sympatric with S. alburnoides.We discuss mechanisms that could lead to the formation of mosaic S. alburnoides and hypothesise about a relaxation of the mechanisms that impose a tight control over mitosis and ploidy control in mixoploids.

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Section: Discussionmentioning

confidence: 91%

Section: Discussionmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ploidy mosaicism and allele-specific gene expression differences in the allopolyploid Squalius alburnoides

et al. 2011

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“…In fact, the presence of ploidy mosaicism has been for many years established and documented in vertebrates [Dawley and Goddard, 1988]. Furthermore, ploidy mosaicism appears often to be associated with allopolyploidy Janko et al, 2007;Bickham and Hanks, 2009].…”

mentioning

confidence: 99%

Natural Pathways towards Polyploidy in Animals: The <b><i>Squalius alburnoides</i></b> Fish Complex as a Model System to Study Genome Size and Genome Reorganization in Polyploids

Collares‐Pereira

Matos

Morgado-Santos

et al. 2013

Cytogenet Genome Res

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When comparing the known picture of polyploidy in animals and in plants, it is possible to recognize some similarities, namely: (i) multiple and recurrent origins in several well-established taxonomic groups; (ii) a strong and regular association with hybridization events; (iii) the production of genotypic diversity; (iv) a rapid genomic reshuffling; (v) a very active role of transposable elements in allopolyploids; (vi) a comparatively privileged occurrence in harsher environments when compared with their diploid relatives, and (vii) gene silencing and divergence of duplicated genes without disruption of duplicated loci. Research on polyploidy was highly biased towards plants during the last century because polyploidy in animals was for long time considered rare, occasional and irrelevant from an evolutionary perspective. However, as empirically observed in plants, genome rediploidization starts in polyploid organisms immediately after the polyploid shock. Given the speed and dynamicity of this process, evidence of genome multiplication is completely erased over time, and hence, only the most recent events are likely to be acknowledged. Although varying in expression between and within taxonomic groups, polyploidy and hybridization are ubiquitous in animals and may be recurrent, fostering evolution. Since evolutionary allopolyploid genomes behave as biologically diploid, zoologists have to challenge the old paradigm of an irrelevant evolutionary role in animals using current genomic and cytogenomic tools. These methods are most likely to reveal the role of polyploid mechanisms in producing evolutionary novelties. Nonsexual complexes are the perfect models to bridge the gap between empirical and theoretical research, while the evolutionary process is in action. Such animal complexes represent a transient stage that, in general, moves towards a polyploid stage, where bisexuality might be recovered, ultimately giving rise to a new gonochoric species. These pathways are herein illustrated by the Iberian allopolyploid Squalius alburnoides. Some general aspects on this fish's complex are updated and reviewed, namely the reproductive modes of the distinct genomotypes, since variable ploidies and genomic combinations occur in natural populations. Most recent data on the mechanisms of gene expression regulation and the importance of the genomic context in driving allelic expression are also included. It was first demonstrated that a regulatory mechanism involving dosage compensation by gene-copy silencing exists in allotriploid females and that allelic expression patterns differed either between genomically equivalent individuals or within the same individual (between tissues and genes). Thus, instead of a whole haplome inactivation, a biased silencing towards repression of a specific allele was observed as well as a reduction of the transcript levels to the diploid state. See also sister article focusing on plants by Tayalé and Parisod in this themed issue

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DNA Content Variation and SNP Diversity Within a Single Population of Asexual Snails

Million

Bhattacharya

Dinges

et al. 2020

Journal of Heredity

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A growing body of research suggests that many clonal populations maintain genetic diversity even without occasional sexual reproduction. The purpose of our study was to document variation in SNP diversity, DNA content, and pathogen susceptibility in clonal lineages of the New Zealand freshwater snail, Potamopyrgus antipodarum. We studied snails that were collected from multiple field sites around a single lake (Lake Alexandrina), as well as isofemale clonal lineages that had been isolated and maintained in the laboratory. We used the KASP method to genotype our samples at 46 nuclear SNP sites, and we used flow cytometry to estimate DNA content. We found high levels of SNP diversity, both in our field samples and in our clonal laboratory lines. We also found evidence of high variation in DNA content among clones, even among clones with identical genotypes across all SNP sites. Controlled pathogen exposures of the laboratory populations revealed variation in susceptibility among distinct clonal genotypes, which was independent of DNA content. Taken together, these results show high levels of diversity among asexual snails, especially for DNA content, and they suggest rapid genome evolution in asexuals.

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Diploid-Triploid Mosaicism and Tissue Ploidy Diversity within <i>Platemys platycephala</i> from Suriname

Cited by 9 publications

References 40 publications

Ploidy mosaicism and allele-specific gene expression differences in the allopolyploid Squalius alburnoides

Ploidy mosaicism and allele-specific gene expression differences in the allopolyploid Squalius alburnoides

Natural Pathways towards Polyploidy in Animals: The <b><i>Squalius alburnoides</i></b> Fish Complex as a Model System to Study Genome Size and Genome Reorganization in Polyploids

DNA Content Variation and SNP Diversity Within a Single Population of Asexual Snails

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