Abstract
Previous studies on grass species suggested that the total centromere size (sum of all centromere sizes in a cell) may be determined by the genome size, possibly because stable scaling is important for proper cell division. However, it is unclear whether this relationship is universal. Here we analyze the total centromere size using the CenH3-immunofluorescence area as a proxy in 130 taxa including plants, animals, fungi, and protists. We verified the reliability of our methodological approach by comparing our measurements with available ChIP-seq-based measurements of the size of CenH3-binding domains. Data based on these two independent methods showed the same positive relationship between the total centromere size and genome size. Our results demonstrate that the genome size is a strong predictor (R-squared = 0.964) of the total centromere size universally across Eukaryotes. We also show that this relationship is independent of phylogenetic relatedness and centromere type (monocentric, metapolycentric, and holocentric), implying a common mechanism maintaining stable total centromere size in Eukaryotes.
Highlights
Previous studies on grass species suggested that the total centromere size may be determined by the genome size, possibly because stable scaling is important for proper cell division
A positive, much weaker, relationship has been observed within species across 26 maize lines differing in genome size[10]. These results indicate that there may be a mechanism maintaining the stable proportion of total centromere size to the genome size that is based on general intracellular scaling p rinciples[7]
The relatively narrow range of the genomes’ proportion occupied by the centromeres (Fig. 3) agreed well with the high total variance explained by the regression model, suggesting that the genome size is a strong predictor of the total centromere size
Summary
Previous studies on grass species suggested that the total centromere size (sum of all centromere sizes in a cell) may be determined by the genome size, possibly because stable scaling is important for proper cell division. A positive, much weaker, relationship has been observed within species across 26 maize lines differing in genome size[10] These results indicate that there may be a mechanism maintaining the stable proportion of total centromere size to the genome size that is based on general intracellular scaling p rinciples[7]. This notion was supported by observation in maize/oat and maize/maize hybrids that centromeres may expand when chromosomes are introduced into larger genomes[9,10]. We considered the analyzed taxa’s phylogenetic relatedness and differences in centromere organization due to possession of monocentric chromosomes (with a single regional centromere), metapolycentric chromosomes (having multiple separated kinetochore regions in the primary constriction12), or holocentric chromosomes (centromere function along the chromosome[13])
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