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Within animals, a positive correlation between genome size and body size has been detected in several taxa but not in others, such that it remains unknown how pervasive this pattern may be. Here, we provide another example of a positive relationship in a group of crustaceans whose genome sizes have not previously been investigated. We analyze genome size estimates for 46 species across the 2 most diverse orders of Class Ostracoda, commonly known as seed shrimps, including 29 new estimates made using Feulgen image analysis densitometry and flow cytometry. Genome sizes in this group range ~80-fold, a level of variability that is otherwise not seen in crustaceans with the exception of some malacostracan orders. We find a strong positive correlation between genome size and body size across all species, including after phylogenetic correction. We additionally detect evidence of XX/XO sex determination in 3 species of marine ostracods where male and female genome sizes were estimated. On average, genome sizes are larger but less variable in Order Myodocopida than in Order Podocopida, and marine ostracods have larger genomes than freshwater species, but this appears to be explained by phylogenetic inertia. The relationship between phylogeny, genome size, body size, and habitat is complex in this system and provides a baseline for future studies examining the interactions of these biological traits. [ABSTRACT FROM AUTHOR]

Heterochromatin distribution and chromosomal rearrangements have been proposed as the main sources of karyotype differences among species of Neotropical primates. This variability suggests that there could be differences at other smaller-scale levels of DNA organization as well. In particular, quantitative differences between genomes result from gains and losses of individual DNA segments, and may result in varying genome sizes ( C-values) among species. In this work, we studied the genomes of 23 individuals from four species in the genus Ateles (Primates: Platyrrhini): A. chamek, A. paniscus, A. belzebuth, and A. geoffroyi. We analyzed genome size and its relationship with the presence of chromosomal rearrangements and patterns of heterochromatin distribution. The C-value presented in this work for Ateles chamek is the first estimate for this species (3.09 ± 0.23 pg), whereas our estimates for A. belzebuth (2.88 ± 0.06 pg) and A. geoffroyi (3.19 ± 0.24 pg) differed from those previously published. Fluorescent in situ hybridization (FISH) and interspecies comparativegenomic hybridization (iCGH) analyses revealed that differences in genome size among species relate to localized blocks in both heterochromatic and euchromatic regions, the latter of which appear to be genetically unstable. There were also quantitative differences in Y chromosome content. It remains to be seen whether the chromosomal characteristics of Ateles here discussed are common to platyrrhine monkeys, but it is clear that these monkeys exhibit some intriguing genomic features worthy of additional exploration. [ABSTRACT FROM AUTHOR]

Much confusion in genome biology results from conflation of possible meanings of the word “function.” We suggest that, in this connection, attention should be paid to evolutionary biologists and philosophers who have previously dealt with this problem. We need only decide that although all genomic structures have effects, only some of them should be said to have functions. Although it will very often be difficult or impossible to establish function (strictly defined), it should not automatically be assumed. We enjoin genomicists in particular to pay greater attention to parsing biological effects. [ABSTRACT FROM PUBLISHER]

Many studies have assessed whether and to what degree students (grade-schoolers to undergraduates), teachers, and the public in general accept and understand evolution. However, very little information has been available about the level of understanding of students pursuing an advanced postgraduate degree in science. The study discussed in this article involved a survey of graduate students from four science colleges at a midsized Canadian university. Encouragingly, the results indicate that graduate students in diverse disciplines exhibit a better understanding of evolutionary concepts than do students at other levels. However, a working knowledge of evolutionary mechanisms may remain elusive, and some misconceptions may persist, even at this advanced level. [ABSTRACT FROM AUTHOR]

This article discusses the use of DNA barcoding for taxonomy purposes. There is much controversy about the barcoding of DNA, which the authors feel stems from misconceptions about it. Several questions are presented and discussed. Views are expressed about whether DNA barcoding is an expedient solution to the decline in alpha taxonomic research. It is emphasized that DNA barcodes do not aim to recover phylogenetic relationships, but seek instead to identify known species and to aid the discovery of new ones.

• Aims Plants and animals represent the first two kingdoms recognized, and remain the two best-studied groups in terms of nuclear DNA content variation. Unfortunately, the traditional chasm between botanists and zoologists has done much to prevent an integrated approach to resolving the C-value enigma, the long-standing puzzle surrounding the evolution of genome size. This grand division is both unnecessary and counterproductive, and the present review aims to illustrate the numerous links between the patterns and processes found in plants and animals so that a stronger unity can be developed in the future.• Scope This review discusses the numerous parallels that exist in genome size evolution between plants and animals, including (i) the construction of large databases, (ii) the patterns of DNA content variation among taxa, (iii) the cytological, morphological, physiological and evolutionary impacts of genome size, (iv) the mechanisms by which genomes change in size, and (v) the development of new methodologies for estimating DNA contents.• Conclusions The fundamental questions of the C-value enigma clearly transcend taxonomic boundaries, and increased communication is therefore urged among those who study genome size evolution, whether in plants, animals or other organisms. [ABSTRACT FROM AUTHOR]

Amphibians have featured prominently in discussions of the C-value enigma, the still-unresolved puzzle regarding the evolution of genome size. Their wide range in nuclear DNA contents and diverse ecological and developmental lifestyles make them excellent subjects for addressing the key elements of the C-value enigma. However, in some cases the importance of work on amphibians appears to be overstated. This is especially true of claims that patterns of variation in salamanders support a particular theory of genome size evolution to the exclusion of others. This study provides a critical re-examination of some of these claims, as well as an investigation of the relationships between genome size, cell and nuclear size, and metabolism in amphibians. The results of these analyses, combined with an overview of previous amphibian genome size literature, strongly indicate the need for a pluralistic approach to the C-value enigma. In particular, it must be recognized that evolutionary forces operating and interacting at several levels of biological organization (of which the genome itself is one) are responsible for the observed patterns in amphibian genome size distributions. © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 79 , 329–339. [ABSTRACT FROM AUTHOR]

Discusses the genome size, or C-value, constraints in birds that illustrated the necessity of pluralistic approaches to complex evolutionary problems. Correlation of cell size with both nucleus size and C-value in birds; Use of published data on cell and nuclear sizes, haploid genome sizes, and active and resting metabolic rates; Recommendation of a pluralistic approach to the C-value enigma.