The Origin, Evolution and Proposed Stabilization of the Terms 'Genome Size' and 'C-Value' to Describe Nuclear DNA Contents

Abstract

We argue that there is a need to maintain the term genome size in a broad sense as a covering term, because it is widely understood, short and phonetically pleasing. Proposals are made for a unified and consensual terminology. In this, 'genome size' should mean the DNA content based on chromosome number x and n, and should be used mainly in a general sense. The necessary distinction of the kinds of genome sizes is made by the adjectives 'monoploid' and the neology 'holoploid'. 'Holoploid genome size' is a shortcut for the DNA content of the whole chromosome complement characteristic for the individual (and by generalization for the population, species, etc.) irrespective of the degree of generative polyploidy, aneuploidies, etc. This term was lacking in the terminology and is for reasons of linguistic consistency indispensable. The abbreviated terms for monoploid and holoploid genome size are, respectively, Cx-value and C-value. Quantitative data on genome size should always indicate the C-level by a numerical prefix, such as 1C, 1Cx, 2C, etc. The proposed conventions cover general fundamental aspects relating to genome size in plants and animals, but do not treat in detail cytogenetic particularities (e.g. haploids, hybrids, etc.) which will need minor extensions of the present scheme in a future paper.

Citogenética de genotipos de uchuva, Physalis peruviana L., y Physalis floridana Rydb., con respuesta diferencial a Fusarium oxysporum

“…El valor para cualquier tipo de célula blanco se puede cuantificar con relación a un contenido estándar en las células de una especie de referencia y en cualquier estado de replicación (Greilhulber et al, 2005); asimismo, los estándares pueden ser corridos secuencialmente en el citómetro o simultáneamente con la muestra ( Johnson et al, 1987). En este estudio se usó como control glóbulos rojos de trucha, los cuales han sido empleados rutinariamente para determinar tamaño del genoma y conocer el nivel de ploidía tanto en plantas como en animales (Galbraith et al, 1983;Aramuganathan y Earle, 1991;Bennett y Leitch, 1995;Thompson et al, 1997; …”

Evolution of genome size and genomic GC content in carnivorous holokinetics (Droseraceae)

“…The analyses of genome size evolution were conducted with monoploid genome size (Cx; i.e. total 2C genome size divided by the ploidy level; Greilhuber et al, 2005) instead of the raw measures of DNA content. The monoploid genome size was log10 transformed prior to all statistical analyses; the GC contents and the chromosome numbers were used as raw values.…”

Genome size in aquatic and wetland plants: fitting with the large genome constraint hypothesis with a few relevant exceptions

“…of the haploid complement of an organism. Greilhuber et al (2005) detailed genome size terminology and established, among others, the terms holoploid (2C, DNA amount of the nucleus of a somatic cell) and monoploid genome size (1Cx, DNA content in a basic chromosome set -x-of an organism). Genome size shows a very large diversity, neither proportional to organism complexity nor according to phylogenetic position and relationships.…”