DNA Underreplication in the Majority of Nuclei in the Drosophila Melanogaster Thorax: Evidence from Suur and Flow Cytometry

Johnston, J. Spencer; Schoener, Molly; McMahon, Dino P.

doi:10.5539/jmbr.v3n1p47

Cited by 10 publications

(19 citation statements)

References 44 publications

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“…The co-preparations show separate fluorescence intensity peaks that differ in position precisely as expected from the genome size estimates (Table 1). Additional evidence of differences was provided by comparison of the proportion of under-replicated DNA in polytene tissues (Figure S2a,b) [36]. For the strains shown, DGRP_208 (169.7 Mb) and DGRP_517 (181 Mb), 88% of the DNA is fully replicated (12% unreplicated) in the smaller genome, while 86.2% of the DNA is fully replicated (13.8% unreplicated) in the larger genome.…”

Section: Resultsmentioning

confidence: 87%

Intrapopulation Genome Size Variation in D. melanogaster Reflects Life History Variation and Plasticity

et al. 2014

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We determined female genome sizes using flow cytometry for 211 Drosophila melanogaster sequenced inbred strains from the Drosophila Genetic Reference Panel, and found significant conspecific and intrapopulation variation in genome size. We also compared several life history traits for 25 lines with large and 25 lines with small genomes in three thermal environments, and found that genome size as well as genome size by temperature interactions significantly correlated with survival to pupation and adulthood, time to pupation, female pupal mass, and female eclosion rates. Genome size accounted for up to 23% of the variation in developmental phenotypes, but the contribution of genome size to variation in life history traits was plastic and varied according to the thermal environment. Expression data implicate differences in metabolism that correspond to genome size variation. These results indicate that significant genome size variation exists within D. melanogaster and this variation may impact the evolutionary ecology of the species. Genome size variation accounts for a significant portion of life history variation in an environmentally dependent manner, suggesting that potential fitness effects associated with genome size variation also depend on environmental conditions.

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Section: Resultsmentioning

confidence: 87%

Intrapopulation Genome Size Variation in D. melanogaster Reflects Life History Variation and Plasticity

et al. 2014

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“…Endopolyploidy has been found in a variety of animals, including many insect orders (Nagl 1976, White 1977, Johnston et al 2004, Aron et al 2005. In insects, the occurrence of endopolyploidy is tissue-dependent and is perhaps best characterized in Drosophila melanogaster, where ploidy levels as high as 1024C are found among the polytene chromosomes of the salivary glands and follicle cells, with lower levels of endopolyploidy occurring throughout the organism (Balbiani 1881, Mulligan and Rasch 1985, Lilly and Duronio 2005, Johnston et al 2013. The highest level of endopolyploidy observed so far is in the insect Bombyx mori, whose silk-producing glands are reported to exceed one million-ploid as a result of intensive artificial selection (Perdix-Gillot 1979).…”

Section: Introductionmentioning

confidence: 99%

Organ-specific patterns of endopolyploidy in the giant ant Dinoponera australis

Scholes¹,

Suarez²,

Smith³

et al. 2014

JHR

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Endoreduplication is an alternative cell cycle that omits cell division such that cellular ploidy increases, generating "endopolyploidy". Endoreduplication is common among eukaryotes and is thought to be important in generalized cell differentiation. Previous research on ants suggests that they endoreduplicate in body segment-dependent manners. In this study, we measured endopolyploidy of specific organs within ant body segments to determine which organs are driving these segment-specific patterns and whether endopolyploidy is related to organ function. We dissected fourteen organs from each of five individuals of Dinoponera australis and measured endopolyploidy of each organ via flow cytometry. Abdominal organs had higher levels of endopolyploidy than organs from the head and thorax, driven by particularly high ploidy levels for organs with digestive or exocrine function. In contrast, organs of the reproductive, muscular, and neural systems had relatively low endopolyploidy. These results provide insight into the segment-specific patterns of endopolyploidy previously reported and into the specific organs that employ endoreduplication in their functional development. Future work aimed at quantifying the metabolic and gene expression effects of endoreduplication will clarify how this often overlooked genomic event contributes to the development and function of specialized organs across the breadth of taxa that are known to endoreduplicate.

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“…A variant of this process is seen in the thorax of Drosophila. Unlike UR in polytene cells, thoracic UR is seen as a stall of DNA synthesis between the G0 and G1 stage, with little evidence for endocycle initiation [16]. An exceptional property of thoracic UR involves the proportion of nuclei underreplicated.…”

Section: Introductionmentioning

confidence: 99%

“…In tissues with polyploidy or polyteny, essentially all nuclei are underreplicated [17]. Yet, for unknown reasons, UR is seen in less than half the nuclei of the thorax [16]. If underreplication is adaptive, it would be expected that every cell would underreplicate.…”

Section: Introductionmentioning

confidence: 99%

Flying High—Muscle-Specific Underreplication in Drosophila

Johnston

Zapalac

Hjelmen

2020

Genes

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Drosophila underreplicate the DNA of thoracic nuclei, stalling during S phase at a point that is proportional to the total genome size in each species. In polytene tissues, such as the Drosophila salivary glands, all of the nuclei initiate multiple rounds of DNA synthesis and underreplicate. Yet, only half of the nuclei isolated from the thorax stall; the other half do not initiate S phase. Our question was, why half? To address this question, we use flow cytometry to compare underreplication phenotypes between thoracic tissues. When individual thoracic tissues are dissected and the proportion of stalled DNA synthesis is scored in each tissue type, we find that underreplication occurs in the indirect flight muscle, with the majority of underreplicated nuclei in the dorsal longitudinal muscles (DLM). Half of the DNA in the DLM nuclei stall at S phase between the unreplicated G0 and fully replicated G1. The dorsal ventral flight muscle provides the other source of underreplication, and yet, there, the replication stall point is earlier (less DNA replicated), and the endocycle is initiated. The differences in underreplication and ploidy in the indirect flight muscles provide a new tool to study heterochromatin, underreplication and endocycle control.

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DNA Underreplication in the Majority of Nuclei in the Drosophila Melanogaster Thorax: Evidence from Suur and Flow Cytometry

Cited by 10 publications

References 44 publications

Intrapopulation Genome Size Variation in D. melanogaster Reflects Life History Variation and Plasticity

Intrapopulation Genome Size Variation in D. melanogaster Reflects Life History Variation and Plasticity

Organ-specific patterns of endopolyploidy in the giant ant Dinoponera australis

Flying High—Muscle-Specific Underreplication in Drosophila

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