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The evolution of genome size in ants.

Tsutsui ND, Suarez AV, Spagna JC, Johnston JS - BMC Evol. Biol. (2008)

Bottom Line: Our results show that ants possess small genomes relative to most other insects, yet genome size varies three-fold across this insect family.Although some previous studies of other taxa have revealed a relationship between genome size and body size, our phylogenetically-controlled analysis of this correlation did not reveal a significant relationship.The small genome sizes of ants, combined with their ecological, evolutionary and agricultural importance, suggest that some of these species may be good candidates for future whole-genome sequencing projects.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Environmental Science, Policy and Management, University of California-Berkeley, Berkeley, CA 94720, USA. ntsutsui@nature.berkeley.edu

ABSTRACT

Background: Despite the economic and ecological importance of ants, genomic tools for this family (Formicidae) remain woefully scarce. Knowledge of genome size, for example, is a useful and necessary prerequisite for the development of many genomic resources, yet it has been reported for only one ant species (Solenopsis invicta), and the two published estimates for this species differ by 146.7 Mb (0.15 pg).

Results: Here, we report the genome size for 40 species of ants distributed across 10 of the 20 currently recognized subfamilies, thus making Formicidae the 4th most surveyed insect family and elevating the Hymenoptera to the 5th most surveyed insect order. Our analysis spans much of the ant phylogeny, from the less derived Amblyoponinae and Ponerinae to the more derived Myrmicinae, Formicinae and Dolichoderinae. We include a number of interesting and important taxa, including the invasive Argentine ant (Linepithema humile), Neotropical army ants (genera Eciton and Labidus), trapjaw ants (Odontomachus), fungus-growing ants (Apterostigma, Atta and Sericomyrmex), harvester ants (Messor, Pheidole and Pogonomyrmex), carpenter ants (Camponotus), a fire ant (Solenopsis), and a bulldog ant (Myrmecia). Our results show that ants possess small genomes relative to most other insects, yet genome size varies three-fold across this insect family. Moreover, our data suggest that two whole-genome duplications may have occurred in the ancestors of the modern Ectatomma and Apterostigma. Although some previous studies of other taxa have revealed a relationship between genome size and body size, our phylogenetically-controlled analysis of this correlation did not reveal a significant relationship.

Conclusion: This is the first analysis of genome size in ants (Formicidae) and the first across multiple species of social insects. We show that genome size is a variable trait that can evolve gradually over long time spans, as well as rapidly, through processes that may include occasional whole-genome duplication. The small genome sizes of ants, combined with their ecological, evolutionary and agricultural importance, suggest that some of these species may be good candidates for future whole-genome sequencing projects.

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Insect genome sizes (in pg, ± SE), based on data from the Animal Genome Size Database [4]. Ants (Formicidae) are represented by the filled black bar. Each family is labeled at the bottom; the respective orders are shown at the top. Numbers above each bar indicate the number of species in each family for which genome sizes have been estimated. When values from the Animal Genome Size Database were presented as a range, we used the midpoint as the value for that species.
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Figure 1: Insect genome sizes (in pg, ± SE), based on data from the Animal Genome Size Database [4]. Ants (Formicidae) are represented by the filled black bar. Each family is labeled at the bottom; the respective orders are shown at the top. Numbers above each bar indicate the number of species in each family for which genome sizes have been estimated. When values from the Animal Genome Size Database were presented as a range, we used the midpoint as the value for that species.

Mentions: Our data increase the number of published genome size estimates for ants from 1 species (Solenopsis invicta) to 41 species. Only three other insect families (Chrysomelidae, Tenebrionidae and Culicidae) have had genomes sizes estimated for more species [4] (Fig. 1). Similarly, only four other orders of insects (Coleoptera, Diptera, Orthoptera and Lepidoptera) have genome sizes estimated for more species [4] (Fig. 1).


The evolution of genome size in ants.

Tsutsui ND, Suarez AV, Spagna JC, Johnston JS - BMC Evol. Biol. (2008)

Insect genome sizes (in pg, ± SE), based on data from the Animal Genome Size Database [4]. Ants (Formicidae) are represented by the filled black bar. Each family is labeled at the bottom; the respective orders are shown at the top. Numbers above each bar indicate the number of species in each family for which genome sizes have been estimated. When values from the Animal Genome Size Database were presented as a range, we used the midpoint as the value for that species.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2268675&req=5

Figure 1: Insect genome sizes (in pg, ± SE), based on data from the Animal Genome Size Database [4]. Ants (Formicidae) are represented by the filled black bar. Each family is labeled at the bottom; the respective orders are shown at the top. Numbers above each bar indicate the number of species in each family for which genome sizes have been estimated. When values from the Animal Genome Size Database were presented as a range, we used the midpoint as the value for that species.
Mentions: Our data increase the number of published genome size estimates for ants from 1 species (Solenopsis invicta) to 41 species. Only three other insect families (Chrysomelidae, Tenebrionidae and Culicidae) have had genomes sizes estimated for more species [4] (Fig. 1). Similarly, only four other orders of insects (Coleoptera, Diptera, Orthoptera and Lepidoptera) have genome sizes estimated for more species [4] (Fig. 1).

Bottom Line: Our results show that ants possess small genomes relative to most other insects, yet genome size varies three-fold across this insect family.Although some previous studies of other taxa have revealed a relationship between genome size and body size, our phylogenetically-controlled analysis of this correlation did not reveal a significant relationship.The small genome sizes of ants, combined with their ecological, evolutionary and agricultural importance, suggest that some of these species may be good candidates for future whole-genome sequencing projects.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Environmental Science, Policy and Management, University of California-Berkeley, Berkeley, CA 94720, USA. ntsutsui@nature.berkeley.edu

ABSTRACT

Background: Despite the economic and ecological importance of ants, genomic tools for this family (Formicidae) remain woefully scarce. Knowledge of genome size, for example, is a useful and necessary prerequisite for the development of many genomic resources, yet it has been reported for only one ant species (Solenopsis invicta), and the two published estimates for this species differ by 146.7 Mb (0.15 pg).

Results: Here, we report the genome size for 40 species of ants distributed across 10 of the 20 currently recognized subfamilies, thus making Formicidae the 4th most surveyed insect family and elevating the Hymenoptera to the 5th most surveyed insect order. Our analysis spans much of the ant phylogeny, from the less derived Amblyoponinae and Ponerinae to the more derived Myrmicinae, Formicinae and Dolichoderinae. We include a number of interesting and important taxa, including the invasive Argentine ant (Linepithema humile), Neotropical army ants (genera Eciton and Labidus), trapjaw ants (Odontomachus), fungus-growing ants (Apterostigma, Atta and Sericomyrmex), harvester ants (Messor, Pheidole and Pogonomyrmex), carpenter ants (Camponotus), a fire ant (Solenopsis), and a bulldog ant (Myrmecia). Our results show that ants possess small genomes relative to most other insects, yet genome size varies three-fold across this insect family. Moreover, our data suggest that two whole-genome duplications may have occurred in the ancestors of the modern Ectatomma and Apterostigma. Although some previous studies of other taxa have revealed a relationship between genome size and body size, our phylogenetically-controlled analysis of this correlation did not reveal a significant relationship.

Conclusion: This is the first analysis of genome size in ants (Formicidae) and the first across multiple species of social insects. We show that genome size is a variable trait that can evolve gradually over long time spans, as well as rapidly, through processes that may include occasional whole-genome duplication. The small genome sizes of ants, combined with their ecological, evolutionary and agricultural importance, suggest that some of these species may be good candidates for future whole-genome sequencing projects.

Show MeSH
Related in: MedlinePlus