Genome Size Determination in Chagas Disease Transmitting Bugs (Hemiptera-Triatominae) by Flow Cytometry

Abstract

Abstract. Because information about genome size in triatomines is scarce and contradictory, we performed DNA quantification by flow cytometry in 13 species belonging to five genera (Dipetalogaster, Eratyrus, Panstrongylus, Rhodnius, and Triatoma) to infer overall tendencies and phylogenetic associations. The results show that the haploid DNA content of the subfamily Triatominae varies nearly 4-fold, from < 0.7 pg in Rhodnius species (0.6 × 10 9 bp) to 2.7 pg in Triatoma delpontei (2.6 × 10 9 bp). Considering that triatomines present similar chromosome numbers, we suggest that genome size differences are the result of variation in the quantity of repetitive DNA sequences localized in hetero and euchromatin. Changes in heterochromatin are particularly important when considering populations or closely related species; in more distant taxa, euchromatic changes also play a role. Our analyses indicate that flow cytometry is a useful tool for population, taxonomic, and evolutionary studies in this subfamily.

Cytogenetics and Genome Evolution in the Subfamily Triatominae (Hemiptera, Reduviidae)

“…These differences coincide with the smaller size of the chromosomes in the genus Rhodnius . Furthermore, species with similar amounts of heterochromatin, but evolutionarily distant, also show major differences in genome size attributable to the amount of euchromatin [Panzera et al, 2007b].…”

“…In recent years, we have applied laser flow cytometry to measure genome size in several species of Triatominae Bargues et al, 2006]. Comparative analysis of 20 species by flow cytometry indicates that the haploid genome size of Triatominae species varies 4-fold, from 0.72 pg in Rhodnius species to 2.90 pg in Triatoma delpontei ( table 2 ) [Panzera et al, 2007b]. The mean haploid genome size for the Triatominae (1.25 8 0.09 pg) is very similar to the value proposed for all Heteroptera (1.18 8 0.18 pg) [Gregory, 2005].…”

High Dynamics of rDNA Cluster Location in Kissing Bug Holocentric Chromosomes (Triatominae, Heteroptera)

“…In T. dimidiata we analyzed specimens from 3 subspecies identified by molecular markers [Bargues et al, 2008], all of them showing the cytotype 1 described by Panzera et al [2006]. In T. infestans we studied several populations from both previously described chromosomal groups, named Andean and non-Andean, which have substantial differences in C-heterochromatin content and genome size [Panzera et al, 2004[Panzera et al, , 2007[Panzera et al, , 2010.…”

Chromosomal divergence and evolutionary inferences in Rhodniini based on the chromosomal location of ribosomal genes

“…The main source of karyotype variation in this subfamily involves changes in chromosome number, differences in C-heterochromatin (such as the number, size and location of C-blocks) and genomic DNA content (Panzera et al 2007(Panzera et al , 2010. However, Rhodniini karyotypes seem to be highly conserved, with no known variations either in the number of autosomes (20) or sex mechanism (XY in males, XX in females).…”

“…However, Rhodniini karyotypes seem to be highly conserved, with no known variations either in the number of autosomes (20) or sex mechanism (XY in males, XX in females). In addition, Rhodniini species exhibit chromosomes of similar size and possess the lowest genomic DNA content of all the triatomines (Panzera et al 2007). Only a few Rhodniini species present C-heterochromatin (Rhodnius colombiensis, Rhodnius nasutus, R. pallescens and Rhodnius pictipes) (Dujardin et al 2002), with only one of these species exhibiting C-band polymorphisms (Gómez-Palacio et al 2008.…”