Uniformity of Radiation-induced Mutation Rates among Different Species

Abrahamson, S.; Bender, Michael A.; Conger, Alan D.; Wolff, Sheldon M.

doi:10.1038/245460a0

Cited by 138 publications

(27 citation statements)

References 20 publications

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“…As an expression of a more general pattern consistent with the above-mentioned scenario, there has been also a tendency toward the continuous increment of the relative importance of the DNA control fraction during the evolutionary complexification (Abrahamson et al, 1973;Omodeo 2010). Obviously, the trend described above was likely accelerated when the global environmental crises (such as the Permian-Triassic one) reduced substantially the numerosity of living taxa, thus creating empty niche spaces for the "new species", which exhibited the stronger and more stable adaptations.…”

Section: Is Biodiversity Aging? Heuristic Questions On the Taxonomic supporting

confidence: 49%

Is biodiversity aging? Heuristic questions on the taxonomic diversity in the Phanerozoic

Amante¹

2018

Biodiversity Journal

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The trend of numerosity component of diversity was analysed from palaeontological data, according to various time intervals and taxonomical ranks. Taxa numerosity of lower (with respect to family), with a nearly exponential increase, vs. higher ranks (from order to macrotaxon), with mainly a logarithmic trend, confirms to follow quite different patterns over time. This dataset seems to fit with a more assortative hypothesis, for higher taxa and a more divisive one for lower taxa. Then, a model was built to quantify the relative weight, over time, of the above hypothetical evolutionary components of various taxa ranks; such ranks were identified, in a palaeontological approach, by the maximum number of recorded taxa or, in a phyletic approach, by the time duration based on genetic data. The trends obtained by this model agree with observed records and the hypothesis, to be verified, of a quite different evolutionary origin of macro-(phylum, class, order ranks) and micro-taxa (genus and species), during the transition between two main time phases: the first (evidently more assortative), mainly linked to the lateral sharing of characters, the second (evidently more divisive), mainly influenced by the ever growing morpho-physio-genetic isolation even for the protection of complex adaptations, as in the present, "modern species". INTRODUCTIONSince evolutionary theory was accepted as the only possible rational explanation of the life diversification in the biosphere -e.g., Gould (2002); see also Mayr (1982), evolutionary processes have received many and different interpretations. Two main question points have been particularly investigated: (i) the basis of the biological variability, and (ii) the factors orienting its evolution: see, e. g., Gould (2002). Moreover, genetics has provided experimental evidence of the "transition" from a species into another species, within a framework that has been defined "microevolution".However, there has been a contextual difficulty in explaining the great differences in morpho-physiological models, occurring among high-rank taxa like phyla, classes, and orders by means of merely micro-evolutionary processes (Stanley, 1979).Therefore, Stanley (1979) hypothesized a "decoupling" of selective ranks, between microevolution (selection among individuals) and macroevolution (species as individual units of selection, in macro-evolution, in analogy with specimens in micro-evolution). KEY WORDSEvolutionary models; genetic timing; macroevolution; taxonomic diversity."Iamque adeo fracta est aetas effetaque tellus vix animalia parva creat quae cuncta creavit saecla …" (Lucretius).

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Section: Is Biodiversity Aging? Heuristic Questions On the Taxonomic supporting

confidence: 49%

Is biodiversity aging? Heuristic questions on the taxonomic diversity in the Phanerozoic

Amante¹

2018

Biodiversity Journal

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“…For example, larvae of P. vanderplanki experience massive DNA damage after anhydrobiosis and efficient DNA repair occurs during the few days following rehydration . In plants, a negative correlation was found between genome size and radiation tolerance (Bennett and Leitch, 2005) and mutation rate was also lower in species with smaller genome size (Abrahamson et al, 1973). Consequently, the small genome size of P. vanderplanki may represent an advantage to avoid the accumulation of deleterious mutations during the DNA repair events associated with cycles of desiccation and rehydration.…”

Section: Discussionmentioning

confidence: 90%

Chironomid Midges (Diptera, Chironomidae) Show Extremely Small Genome Sizes

et al. 2015

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“…For example, Abrahamson et al (1973) found a linear correlation between mutation per rad per locus and lC DNA amount for different organisms including two angiosperms [ Fig. 8(a)].…”

Section: Ionizing Radiationmentioning

confidence: 99%

“…8. Relationships between nuclear characters and radio-sensitivity, (a) The relationship between forward mutation rate per locus per rad and \C DNA amount [modified from Abrahamson et al (1973) and using the DNA amount for tomato {Lycopersicon esculentum Mill.) measured by Bennett & Smith (1976)]; (b) the relationship between nuclear volume and radio-sensitivity in 23 species of plants [redrawn from Sparrow & Miksche (1961)] and (c) the relationship between acute lethal exposure to ionizing radiation and interphase chromosome volume (ICV) for 15 herbaceous (A) and 12 woody (#) plant species [redrawn from Sparrow et al (1965)].…”

Section: Ionizing Radiationmentioning

confidence: 99%

Variation in Genomic Form in Plants and Its Ecological Implications

Bennett¹

1987

New Phytologist

358

198

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SUMMARYThe gross form of the nuclear genome varies greatly among plant species in both anatomy and genetic organization. Chromosome number (n) ranges from 2 to over 600, and ploidy from 1 to over 20. The amount of DNA in the unreplicated haplophase genome (the lC value) differs by more than 2500-fold among angiosperms. Although it has been questioned since the 1930s whether such variation is of adaptive significance and whether it is related, perhaps causally, with environmental factors, no direct or causal links have yet been found. However, variation in DNA C-value has far-reaching biological consequences and can be of considerable adaptive and hence ecological significance. Strikingly precise interspecific relationships exist between DNA C-value and many diverse phenotypic characters at the cellular level, and DNA can affect the phenotype in two ways, firstly by expression of its genie content and, secondly, by the biophysical effects of its mass and volume, the latter defined as nucleotypic effects. Nucleotypic variation in DNA C-value sets absolute limits to both the minimum size and mass of the basic unit of plant anatomy (i.e. the cell) and the minumuni time needed to produce a similar cell with newly synthesized organic molecules. Moreover, in complex multicellular vascular plants, such effects at successive cell cycles are additive, so that DNA C-value influences many characters, including growth rate, seed weight, minimum generation time and type of life-cycle. Thus, the nucleotype profoundly affects where, when and how plants grow. Selection for a particular genomic form acting on its spatial or temporal consequences may occur at various levels ranging from the cell to the whole organism and may operate throughout the life-cycle or at just one stage. DNA C-value is often indirectly related to environmental factors which determine time-limited environments via selection acting on the temporal phenotypic consequences of nucleotypic variation. However, in the case of radio-sensitivity, selection for a low DNA C-value may act directly on the nucleotype itself, as the size of the nuclear DNA target directly affects the ability of the plant to survive.Key words: Plant genomic form, DNA C-value, DNA amount, cytoecology, nucleotype. GENOMIC FORM -CONSTANCY AND VARIATIONMany great discoveries in biology this century have concerned the genome and its form -that the genetic material is DNA, that this has a double helical structure, that this form is important in semi-conservative replication and cell heredity, and that the genetic code is written as triplets of nucleotides. In these important respects, genomic form is the same in all eukaryotes. These discoveries emphasized aspects of constancy in genomic form, except for the nucleotide base sequences of genie DNA whose variation determines the phenotype. However, much cytological work also showed that the genome can vary greatly in both anatomy and genetic organization among taxa.This review is concerned with variation in aspects of gross genomic form in nuclei...

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Uniformity of Radiation-induced Mutation Rates among Different Species

Cited by 138 publications

References 20 publications

Is biodiversity aging? Heuristic questions on the taxonomic diversity in the Phanerozoic

Is biodiversity aging? Heuristic questions on the taxonomic diversity in the Phanerozoic

Chironomid Midges (Diptera, Chironomidae) Show Extremely Small Genome Sizes

Variation in Genomic Form in Plants and Its Ecological Implications

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