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Lidia Poggio

Bio: Lidia Poggio is an academic researcher from Facultad de Ciencias Exactas y Naturales. The author has contributed to research in topics: Ploidy & Polyploid. The author has an hindex of 24, co-authored 116 publications receiving 1764 citations. Previous affiliations of Lidia Poggio include University of Buenos Aires & National Scientific and Technical Research Council.
Topics: Ploidy, Polyploid, Genome size, B chromosome, Genome


Papers
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Journal ArticleDOI
TL;DR: There is an optimum nucleotype for each population and that Bs are tolerated so long as this nucleotype is not exceeded, and analysis of total DNA content and the number of DAPI bands indicates that in populations with high A-DNA content the increase in genome size could be masked.

99 citations

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TL;DR: The data on genetic variation concerning the percentage of polymorphic loci ( P) and the expected mean of heterozygotes per locus ( H) shows that arboreal species belonging to sect.

82 citations

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TL;DR: It is concluded that diploids with lower DNA content grow in high-elevation sites having greater rainfall but lower water availability and that the C-value plays an important role in the ability of the species to adapt to different growing conditions.

70 citations

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TL;DR: In order to clarify the relationships among southern South American (sSA) representatives of the genus Ilex, an amplified fragment length polymorphism (AFLP) analysis was accomplished and revealed that individuals belonging to the same morpho-species formed coherent clades.
Abstract: In order to clarify the relationships among southern South American (sSA) representatives of the genus Ilex, an amplified fragment length polymorphism (AFLP) analysis was accomplished. In addition, the phylogenetic relationships of the species were studied using ribosomal internal transcribed spacer (ITS) sequence data alone and in combination with AFLP data, taking into account the possible existence of paralogous sequences and the influence of alignment parameters. To explore stability of phylogenetic hypotheses, a sensitivity analysis was performed using 15 indel-substitution models. Within each species assayed, the AFLPs allowed the recognition of several diagnostic bands. Furthermore, the AFLP analysis revealed that individuals belonging to the same morpho-species formed coherent clades. In addition, some cases of geographical association were noted. Studies on ITS sequences revealed divergence between data obtained herein and sequence data downloaded from GenBank. The sensitivity analyses yielded different interspecific hypotheses of relationships. Notwithstanding, analyses of the ITS data alone and in combination with AFLPs, rendered clades stable to variation in the analytical parameters. Topologies obtained for the AFLPs, the ITS data alone and the combined analyses, demonstrated the existence of a group formed by I. argentina, I. brasiliensis, I. brevicuspis, I. integerrima, and I. theezans, and that I. dumosa and I. paraguariensis were distantly related to the former. Incongruence with traditional taxonomical treatments was found.

63 citations

Journal ArticleDOI
TL;DR: There is a maximum limit to the mass of nuclear DNA so that Bs are tolerated as long as this maximum limit is not exceeded, and this indicates that there is a close interrelationship between the DNA content of A chromosomes and doses of Bs.
Abstract: Twenty-one native populations (1120 individuals) of maize from Northern Argentina were studied. These populations, which belong to 13 native races, were cultivated at different altitudes (80‐3620 m). Nineteen of the populations analyzed showed B chromosome (Bs) numerical polymorphism. The frequency of individuals with Bs varied from 0 to 94%. The number of Bs per plant varied from 0 to 8 Bs, with the predominant doses being 0, 1, 2, and 3. Those populations with varying number of Bs showed a positive and statistically significant correlation of mean number of Bs with altitude. The DNA content, in plants without Bs (A-DNA)(2n 5 20), of 17 populations of the 21 studied was determined. A 36% variation (5.0‐6.8 pg) in A-DNA content was found. A significant negative correlation between A-DNA content and altitude of cultivation and between A-DNA content and mean number of Bs was found. This indicates that there is a close interrelationship between the DNA content of A chromosomes and doses of Bs. These results suggest that there is a maximum limit to the mass of nuclear DNA so that Bs are tolerated as long as this maximum limit is not exceeded.

58 citations


Cited by
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Journal ArticleDOI
TL;DR: A detailed review of the debate surrounding the C‐value enigma, the various theories proposed to explain it, and the evidence in favour of a causal connection between DNA content and cell size is provided.
Abstract: Variation in DNA content has been largely ignored as a factor in evolution, particularly following the advent of sequence-based approaches to genomic analysis. The significant genome size diversity among organisms (more than 200 000-fold among eukaryotes) bears no relationship to organismal complexity and both the origins and reasons for the clearly non-random distribution of this variation remain unclear. Several theories have been proposed to explain this ‘C-value enigma’ (heretofore known as the ‘C-value paradox’), each of which can be described as either a ‘mutation pressure’ or ‘optimal DNA’ theory. Mutation pressure theories consider the large portion of non-coding DNA in eukaryotic genomes as either ‘junk’ or ‘selfish’ DNA and are important primarily in considerations of the origin of secondary DNA. Optimal DNA theories differ from mutation pressure theories by emphasizing the strong link between DNA content and cell and nuclear volumes. While mutation pressure theories generally explain this association with cell size as coincidental, the nucleoskeletal theory proposes a coevolutionary interaction between nuclear and cell volume, with DNA content adjusted adaptively following shifts in cell size. Each of these approaches to the C-value enigma is problematic for a variety of reasons and the preponderance of the available evidence instead favours the nucleotypic theory which postulates a causal link between bulk DNA amount and cell volume. Under this view, variation in DNA content is under direct selection via its impacts on cellular and organismal parameters. Until now, no satisfactory mechanism has been presented to explain this nucleotypic effect. However, recent advances in the study of cell cycle regulation suggest a possible ‘gene–nucleus interaction model’ which may account for it. The present article provides a detailed review of the debate surrounding the C-value enigma, the various theories proposed to explain it, and the evidence in favour of a causal connection between DNA content and cell size. In addition, a new model of nucleotypic influence is developed, along with suggestions for further empirical investigation. Finally, some evolutionary implications of genome size diversity are considered, and a broadening of the traditional ‘biological hierarchy’ is recommended.

640 citations

Journal ArticleDOI
TL;DR: It is found that structural variations are pervasive in the Z. mays genome and are enriched at loci associated with important traits and the larger Tripsacum genome can be explained by transposable element abundance rather than an allopolyploid origin.
Abstract: Whereas breeders have exploited diversity in maize for yield improvements, there has been limited progress in using beneficial alleles in undomesticated varieties. Characterizing standing variation in this complex genome has been challenging, with only a small fraction of it described to date. Using a population genetics scoring model, we identified 55 million SNPs in 103 lines across pre-domestication and domesticated Zea mays varieties, including a representative from the sister genus Tripsacum. We find that structural variations are pervasive in the Z. mays genome and are enriched at loci associated with important traits. By investigating the drivers of genome size variation, we find that the larger Tripsacum genome can be explained by transposable element abundance rather than an allopolyploid origin. In contrast, intraspecies genome size variation seems to be controlled by chromosomal knob content. There is tremendous overlap in key gene content in maize and Tripsacum, suggesting that adaptations from Tripsacum (for example, perennialism and frost and drought tolerance) can likely be integrated into maize.

602 citations

Journal ArticleDOI
TL;DR: The results suggest that loss of DNA following polyploid formation, or genome downsizing, may be a widespread phenomenon of considerable biological significance and the nature of the evolutionary forces that may be driving DNA loss are discussed.
Abstract: All else being equal, polyploids are expected to have larger C-values (amount of DNA in the unreplicated gametic nucleus) than their diploid progenitors, increasing in direct proportion with ploidy. This expectation is observed in some polyploid series, especially those newly formed, but there are examples suggesting that C-values in particular polyploids are less than expected. The availability of the Angiosperm DNA C-values database (http:// www.rbgkew.org.uk/cvavhomepage.html) has allowed this question to be addressed across a broad range of angiosperms and has revealed striking results deviating from expectation: (i) mean 1C DNA amount did not increase in direct proportion with ploidy, and (ii) mean DNA amount per basic genome (calculated by dividing the 2C value by ploidy) tended to decrease with increasing ploidy. These results suggest that loss of DNA following polyploid formation, or genome downsizing, may be a widespread phenomenon of considerable biological significance. Recent advances in our understanding of the molecular events that take place following polyploid formation together with new data on how DNA amounts can both increase and decrease provide some insights into how genome downsizing may take place. The nature of the evolutionary forces that may be driving DNA loss are also discussed.

594 citations