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Teixeira GA, Barros LAC, Silveira LI, Orivel J, Lopes DM, Aguiar HJAC. Karyotype conservation and genomic organization of repetitive sequences in the leaf-cutting ant Atta cephalotes (Linnaeus, 1758) (Formicidae: Myrmicinae). Genome 2022; 65:525-535. [PMID: 35973225 DOI: 10.1139/gen-2021-0129] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Leaf-cutting ants are among the New World's most conspicuous and studied ant species due to their notable ecological and economic role. Cytogenetic studies carried out in Atta show remarkable karyotype conservation among the species. We performed classical cytogenetics and physical mapping of repetitive sequences in the leaf-cutting ant Atta cephalotes, the type species of the genus. Our goal was to test the karyotype conservation in Atta and to start to understand the genomic organization and diversity regarding repetitive sequences in leaf-cutting ants. Atta cephalotes showed 2n=22 (18m+2sm+2st) chromosomes. The heterochromatin followed a centromeric pattern, and the GC-rich regions and 18S rDNA clusters were co-located interstitially in the 4th metacentric pair. These cytogenetic characteristics were observed in other Atta species that had previously been studied, confirming the karyotype conservation in Atta. Evolutionary implications regarding the conservation of the chromosome number in leaf-cutting ants are discussed. Telomeric motif (TTAGG)n was detected in A. cephalotes as observed in other ants. Five out of the 11 microsatellites showed a scattered distribution exclusively on euchromatic areas of the chromosomes. Repetitive sequences mapped on the chromosomes of A. cephalotes are the first insights into genomic organization and diversity in leaf-cutting ants, useful in further comparative studies.
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Multiple heterochromatin diversification events in the genome of fungus-farming ants: insights from repetitive sequences. Chromosoma 2022; 131:59-75. [PMID: 35325297 DOI: 10.1007/s00412-022-00770-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 01/18/2022] [Accepted: 02/21/2022] [Indexed: 11/03/2022]
Abstract
A substantial portion of the eukaryotic genome includes repetitive DNA, which is important for its stability, regulation, and architecture. Fungus-farming ant genomes show remarkable structural rearrangement rates that were necessary for the establishment of their agriculture-based lifestyle, highlighting the relevance of this peculiar group in understanding the repetitive portion of ant genome. Chromosomal banding studies are in accordance with genomic data because they show that repetitive heterochromatic sequences of basal and derivative Attina species are GC-rich, an uncommon trait in Formicidae. To understand the evolutionary dynamics of heterochromatin in Attina, we compared GC-rich heterochromatin patterns between the Paleoattina and Neoattina clades of this subtribe. To this end, we hybridized the Mrel-C0t probe (highly and moderately repetitive DNA) obtained from Mycetomoellerius relictus, Neoattina with GC-rich heterochromatin, in karyotypes of Paleoattina and Neoattina species. Additionally, we mapped the repetitive sequences (GA)15 and (TTAGG)6 in species of the two clades to investigate their organization and evolutionary patterns in the genome of Attina. The Mrel-C0t probe marked the heterochromatin in M. relictus, in other Mycetomoellerius spp., and in species of Mycetarotes, Cyphomyrmex, and Sericomyrmex (Neoattina). In Mycetomoellerius urichii, only pericentromeric heterochromatin was marked with Mrel-C0t. No marking was observed in Paleoattina species or in Atta and Acromyrmex (Neoattina). These results indicated that different evolutionary events led to heterochromatin differentiation in Attina. The most likely hypothesis is that GC-rich heterochromatin arose in the common ancestor of the two clades and accumulated various changes throughout evolution. The sequences (GA)15 and (TTAGG)6 located in euchromatin and telomeres, respectively, showed more homogeneous results among the species.
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Cardoso DC, Cristiano MP. Karyotype Diversity, Mode, and Tempo of the Chromosomal Evolution of Attina (Formicidae: Myrmicinae: Attini): Is There an Upper Limit to Chromosome Number? INSECTS 2021; 12:insects12121084. [PMID: 34940172 PMCID: PMC8707115 DOI: 10.3390/insects12121084] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 11/29/2021] [Accepted: 11/30/2021] [Indexed: 12/02/2022]
Abstract
Simple Summary Ants are an important insect group that includes a considerable number of species. Along with this diversity in species, they also exhibit a wide variation in chromosome numbers, from 1 up to 60 chromosomes. DNA molecules can be counted in a specific stage of the cell life cycle and quantified. These DNA molecules are very tightly packed together with several proteins and are called chromosomes. Each species shows a specific number of chromosomes with different shapes and sizes, as well as different quantities of DNA. We can use such information (the number of chromosomes, shape of the chromosomes, and quantity of DNA) as morphological attributes to study evolution at the species level. In this study, we describe new karyotypes of several ant species. In addition, from previous studies, we have compiled all the available information regarding the chromosome number and DNA quantity in fungus-farming ant cells. Different processes, called rearrangements, can change chromosomes over time, producing new character states. Such states can be tracked, along with the species and groups of similar species, using their relationships to identify patterns. We use DNA sequences to reconstruct the relationships of fungus-farming ant species (molecular phylogeny). By comparing such phylogeny with the chromosome number and DNA quantity, we discuss the evolution of chromosomes and DNA quantity (or genome size), and the potential limits to these features across fungus-farming ants. Abstract Ants are an important insect group that exhibits considerable diversity in chromosome numbers. Some species show only one chromosome, as in the males of the Australian bulldog ant Myrmecia croslandi, while some have as many as 60 chromosomes, as in the males of the giant Neotropical ant Dinoponera lucida. Fungus-growing ants are a diverse group in the Neotropical ant fauna, engaged in a symbiotic relationship with a basidiomycete fungus, and are widely distributed from Nearctic to Neotropical regions. Despite their importance, new chromosome counts are scarcely reported, and the marked variation in chromosome number across species has been poorly studied under phylogenetic and genome evolutionary contexts. Here, we present the results of the cytogenetic examination of fungus-farming ants and compile the cytogenetic characteristics and genome size of the species studied to date to draw insights regarding the evolutionary paths of karyotype changes and diversity. These data are coupled with a fossil-calibrated phylogenetic tree to discuss the mode and tempo of chromosomal shifting, considering whether there is an upper limit for chromosome number and genome size in ants, using fungus-farming ants as a model study. We recognize that karyotypes are generally quite variable across fungus-farming ant phylogeny, mostly between genera, and are more numerically conservative within genera. A low chromosome number, between 10 and 12 chromosomes, seems to present a notable long-term evolutionary stasis (intermediate evolutionary stasis) in fungus-farming ants. All the genome size values were inside a limited spectrum below 1 pg. Eventual departures in genome size occurred with regard to the mean of 0.38 pg, indicating that there is a genome, and likely a chromosome, number upper limit.
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Barros LAC, de Aguiar HJAC, Teixeira GA, de Souza DJ, Delabie JHC, Mariano CDSF. Cytogenetic studies on the social parasite Acromyrmex ameliae (Formicidae: Myrmicinae: Attini) and its hosts reveal chromosome fusion in Acromyrmex. ZOOL ANZ 2021. [DOI: 10.1016/j.jcz.2021.06.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Teixeira GA, de Aguiar HJAC, Petitclerc F, Orivel J, Lopes DM, Barros LAC. Evolutionary insights into the genomic organization of major ribosomal DNA in ant chromosomes. INSECT MOLECULAR BIOLOGY 2021; 30:340-354. [PMID: 33586259 DOI: 10.1111/imb.12699] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 01/28/2021] [Accepted: 02/08/2021] [Indexed: 06/12/2023]
Abstract
The major rDNA genes are composed of tandem repeats and are part of the nucleolus organizing regions (NORs). They are highly conserved and therefore useful in understanding the evolutionary patterns of chromosomal locations. The evolutionary dynamics of the karyotype may affect the organization of rDNA genes within chromosomes. In this study, we physically mapped 18S rDNA genes in 13 Neotropical ant species from four subfamilies using fluorescence in situ hybridization. Furthermore, a survey of published rDNA cytogenetic data for 50 additional species was performed, which allowed us to detect the evolutionary patterns of these genes in ant chromosomes. Species from the Neotropical, Palearctic, and Australian regions, comprising a total of 63 species from 19 genera within six subfamilies, were analysed. Most of the species (48 out of 63) had rDNA genes restricted to a single chromosome pair in their intrachromosomal regions. The position of rDNA genes within the chromosomes appears to hinder their dispersal throughout the genome, as translocations and ectopic recombination are uncommon in intrachromosomal regions because they can generate meiotic abnormalities. Therefore, rDNA genes restricted to a single chromosome pair seem to be a plesiomorphic feature in ants, while multiple rDNA sites, observed in distinct subfamilies, may have independent origins in different genera.
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Affiliation(s)
- G A Teixeira
- Programa de Pós-graduação em Biologia Celular e Estrutural, Universidade Federal de Viçosa, Viçosa, Brazil
- Laboratório de Citogenética de Insetos, Departamento de Biologia Geral, Universidade Federal de Viçosa, Viçosa, Brazil
| | - H J A C de Aguiar
- Universidade Federal do Amapá, Campus Binacional, BR 156, n° 3051, Bairro Universidade, Oiapoque, 68980-000, Brazil
| | - F Petitclerc
- CNRS, UMR EcoFoG, AgroParisTech, CIRAD, INRA, Université de Guyane, Université des Antilles, Campus Agronomique, Kourou, France
| | - J Orivel
- CNRS, UMR EcoFoG, AgroParisTech, CIRAD, INRA, Université de Guyane, Université des Antilles, Campus Agronomique, Kourou, France
| | - D M Lopes
- Laboratório de Citogenética de Insetos, Departamento de Biologia Geral, Universidade Federal de Viçosa, Viçosa, Brazil
| | - L A C Barros
- Universidade Federal do Amapá, Campus Binacional, BR 156, n° 3051, Bairro Universidade, Oiapoque, 68980-000, Brazil
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de Aguiar HJAC, Barros LAC, Silveira LI, Petitclerc F, Etienne S, Orivel J. Cytogenetic data for sixteen ant species from North-eastern Amazonia with phylogenetic insights into three subfamilies. COMPARATIVE CYTOGENETICS 2020; 14:43-60. [PMID: 32021662 PMCID: PMC6989564 DOI: 10.3897/compcytogen.v14i1.46692] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 12/03/2019] [Indexed: 06/10/2023]
Abstract
Ants play essential roles in most terrestrial ecosystems and may be considered pests for agriculture and agroforestry. Recent morphological and molecular data have challenged conventional ant phylogeny and the interpretation of karyotypic variations. Existing Neotropical ant cytogenetic data focus on Atlantic rainforest species, and provide evolutionary and taxonomic insight. However, there are data for only 18 Amazonian species. In this study, we describe the karyotypes of 16 ant species belonging to 12 genera and three subfamilies, collected in the Brazilian state of Amapá, and in French Guiana. The karyotypes of six species are described for the first time, including that of the South American genus Allomerus Mayr, 1878. The karyotype of Crematogaster Lund, 1831 is also described for the first time for the New World. For other species, extant data for geographically distinct populations was compared with our own data, e.g. for the leafcutter ants Acromyrmex balzani (Emery, 1890) and Atta sexdens (Linnaeus, 1758). The information obtained for the karyotype of Dolichoderus imitator Emery, 1894 differs from extant data from the Atlantic forest, thereby highlighting the importance of population cytogenetic approaches. This study also emphasizes the need for good chromosome preparations for studying karyotype structure.
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Affiliation(s)
| | - Luísa Antônia Campos Barros
- Universidade Federal do Amapá, Campus Binacional – Oiapoque, BR 156, n°3051 Bairro Universidade, 68980-000, Oiapoque, Amapá, Brazil
| | - Linda Inês Silveira
- Laboratório de Sistemática Molecular Beagle, Universidade Federal de Viçosa, Departamento de Biologia Animal, Av. P. H. Rolfs, s/n, 35570-900, Viçosa, Minas Gerais, Brazil
| | - Frédéric Petitclerc
- CNRS, UMR EcoFoG, AgroParisTech, CIRAD, INRA, Université de Guyane, Université des Antilles, Campus Agronomique, BP 316, 97379 Kourou Cedex, France
| | - Sandrine Etienne
- INRA, UMR EcoFoG, AgroParisTech, CIRAD, CNRS, Université de Guyane, Université des Antilles, Campus Agronomique, BP 316, 97379 Kourou Cedex, France
| | - Jérôme Orivel
- CNRS, UMR EcoFoG, AgroParisTech, CIRAD, INRA, Université de Guyane, Université des Antilles, Campus Agronomique, BP 316, 97379 Kourou Cedex, France
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Pereira TTP, dos Reis ACCC, Cardoso DC, Cristiano MP. Molecular phylogenetic reconstruction and localization of the (TTAGG)n telomeric repeats in the chromosomes of Acromyrmex striatus (Roger, 1863) suggests a lower ancestral karyotype for leafcutter ants (Hymenoptera). COMPARATIVE CYTOGENETICS 2018; 12:13-21. [PMID: 29362670 PMCID: PMC5770561 DOI: 10.3897/compcytogen.v12i1.21799] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Accepted: 11/27/2017] [Indexed: 05/24/2023]
Abstract
Chromosome counts and karyotype characterization have proved to be important features of a genome. Chromosome changes during the diversification of ants might play an important role, given the diversity and success of Formicidae. Comparative karyotype analyses on ants have enriched and helped ant systematics. Among leafcutter ants, two major chromosome counts have been described, one frequent in Atta Fabricius, 1804 (2n = 22 in all Atta spp. whose karyotype is known) and the other frequent in Acromyrmex Mayr, 1865 (2n = 38 in the majority of species whose karyotype is known). The main exception is Acromyrmex striatus (Roger, 1863), which harbors a diploid chromosome set of 22. Here we describe the use of fluorescence in situ hybridization (FISH) with telomeric probes with (TTAGG)6 repeats to describe the telomere composition of A. striatus and to recover potential interstitial non-telomeric signals that may reflect fusion events during the evolution of leafcutter lineage from 38 to 22 chromosomes. Further, we reconstruct the ancestral chromosome numbers of the leafcutter clade based on a recently proposed molecular phylogenetic hypothesis and phylogenomic tree. Distinct signals have been observed in both extremities on the telomere chromosomes of A. striatus. Non-telomeric signals have not been retrieved in our analysis. It could be supposed that the low-numbered karyotype indeed represents the ancestral chromosome number of leafcutters. The phylogenetic reconstruction also recovered a low chromosome number from the diverse approaches implemented, suggesting that n = 11 is the most likely ancestral karyotype of the leafcutter ants and is a plesiomorphic feature shared between A. striatus and Atta spp.
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Affiliation(s)
- Tássia Tatiane Pontes Pereira
- Departamento de Biodiversidade, Evolução e Meio Ambiente, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil
- Programa de Pós-graduação em Genética, Universidade Federal do Paraná, Curitiba, PR, Brazil
| | | | - Danon Clemes Cardoso
- Departamento de Biodiversidade, Evolução e Meio Ambiente, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil
- Programa de Pós-graduação em Genética, Universidade Federal do Paraná, Curitiba, PR, Brazil
| | - Maykon Passos Cristiano
- Departamento de Biodiversidade, Evolução e Meio Ambiente, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil
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Comparative physical mapping of 18S rDNA in the karyotypes of six leafcutter ant species of the genera Atta and Acromyrmex (Formicidae: Myrmicinae). Genetica 2017. [DOI: 10.1007/s10709-017-9970-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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de Aguiar HJAC, Barros LAC, Alves DR, Mariano CDSF, Delabie JHC, Pompolo SDG. Cytogenetic studies on populations of Camponotus rufipes (Fabricius, 1775) and Camponotus renggeri Emery, 1894 (Formicidae: Formicinae). PLoS One 2017; 12:e0177702. [PMID: 28520797 PMCID: PMC5433764 DOI: 10.1371/journal.pone.0177702] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 05/02/2017] [Indexed: 12/22/2022] Open
Abstract
Two valid ant species, Camponotus rufipes and Camponotus renggeri, have recently been the subject of a broad discussion with reference to taxa synonymization. Both species are quite common among the Neotropical myrmecofauna and share some unique traits, such as the shape of the scape and the pilosity patterns of the tibiae and scapes. A single morphological trait can help distinguish these species; however, only a combination of different approaches can enlighten our view of the complex phylogenetic relationships prevailing in the different populations of these two taxa. Therefore, focusing on the taxonomic issues concerning these two species, a cytogenetic survey including 10 populations of C. rufipes and two populations of C. renggeri was performed. In order to better understand the extent of the relationship between C. rufipes and C. renggeri, two common Neotropical Camponotus species, C. atriceps and C. cingulatus were taken as outgroups. All four species of Camponotus that were studied had 2n = 40 chromosomes (4sm+34st+2t); however, the abundance of chromosome rearrangements observed, combined with several chromosome markers, suggest that C. rufipes and C. renggeri are two good distinct species although closely related. The already reported chromosome translocation 2n = 39 (1m+4sm+32st+2t) for C. rufipes has been found in different populations as in the unprecedented chromosome inversions found both in C. rufipes and in C. renggeri populations. Within the C. renggeri chromosome inversions, both the heterozygous state 2n = 40 (1m+3sm+34st+2t) and the homozygous state, 2n = 40 (2m+2sm+34st+2t) were identified. However, only heterozygous specimens for chromosome inversions were found among C. rufipes, with karyotype configurations distinct from those found in C. renggeri, with 2n = 40 (1m+4sm+34st+2t). None of the populations studied showed signs of mosaic individuals. With respect to rDNA clusters, the 18S rDNA seemed to be more restricted inside the genome, as C. renggeri showed four 18S rDNA clusters, whereas, C. rufipes, C. atriceps, and C. cingulatus showed only two clusters. The chromosome locations of the 5S rDNA clusters were pointed for the first time in Formicidae, and showed itself to be more widely spread over the genome. By combining different chromosome banding approaches it was possible to demonstrate the crucial importance that chromosome inversions played on the karyotype evolution within these ants. The results also showed that chromosome translocations might be a consequence of the chromatin dynamic condition observed among Camponotus species. The homozygosis condition found in a C. renggeri from a Brazilian savanna population for chromosome inversions and the contrasting heterozygous condition for a different kind of chromosome inversion in C. rufipes from the Brazilian coastal rainforest, opens the window for a chromosome race hypothesis within the group C. renggeri and C. rufipes. The wide distribution, rich ecological interactions, genetic diversity, and morphological variability among C. renggeri and C. rufipes justify questioning of the actual taxonomic status of these species. The answer of this puzzle is clear when observing the number of 18S rDNA clusters of these ants, as C. rufipes has only two clusters whereas C. renggeri has four.
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Affiliation(s)
- Hilton Jeferson Alves Cardoso de Aguiar
- Programa de Pós-graduação em Genética e Melhoramento, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
- Universidade Federal do Amapá, Campus Binacional, Oiapoque, Amapa, Brazil
- * E-mail:
| | - Luísa Antônia Campos Barros
- Programa de Pós-graduação em Genética e Melhoramento, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
- Universidade Federal do Amapá, Campus Binacional, Oiapoque, Amapa, Brazil
| | - Danúbia Rodrigues Alves
- Programa de Pós-graduação em Genética e Melhoramento, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Cléa dos Santos Ferreira Mariano
- Laboratório de Mirmecologia, CEPEC/CEPLAC, Itabuna, Bahia, Brazil
- Departamento de Ciências Biológicas, Universidade Estadual de Santa Cruz, Ilhéus, Bahia, Brazil
| | - Jacques Hubert Charles Delabie
- Departamento de Ciências Biológicas, Universidade Estadual de Santa Cruz, Ilhéus, Bahia, Brazil
- Departamento de Ciências Agrárias e Ambientais, Universidade Estadual de Santa Cruz, Ilhéus, Bahia, Brazil
| | - Silvia das Graças Pompolo
- Programa de Pós-graduação em Genética e Melhoramento, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
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Cardoso DC, Pereira TTP, Cordeiro AL, Cristiano MP. Cytogenetic data on the agro-predatory ant Megalomyrmex incisus Smith, 1947 and its host, Mycetophylax conformis (Mayr, 1884) (Hymenoptera, Formicidae). COMPARATIVE CYTOGENETICS 2017; 11:45-53. [PMID: 28919948 PMCID: PMC5599698 DOI: 10.3897/compcytogen.v11i1.10842] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 11/18/2016] [Indexed: 06/07/2023]
Abstract
We provide the first karyotype description of the agro-predatory ant species Megalomyrmex incisus Smith, 1947 (Myrmicinae, Formicidae), and chromosome counts of its host Mycetophylax conformis (Mayr, 1884) (Myrmicinae, Formicidae) from geographically distinct populations. Colonies of both species were sampled from coastal areas of Ilhéus, Bahia, Brazil, and transferred to the laboratory. Metaphase spreads were prepared from the cerebral ganglia of defecated larvae. The slides were examined and pictures of the best metaphases were taken. The chromosome number for Megalomyrmex incisus was 2n=50 and n=25. The karyotype of this species consists of 20 metacentric and 5 submetacentric pairs. Thus, the karyotype formula of the diploid set was 2K=40M + 10SM and a fundamental number FN=100. The host species Mycetophylax conformis has 2n=30 and the karyotype consisting of 11 metacentric and 4 submetacentric pairs. The karyotype formula was 2K=22M + 8SM, and a fundamental number FN=60. Megalomyrmex incisus showed a slightly higher chromosome number, placed at the marginal range of the known distribution of haploid karyotypes of the Myrmicinae. The chromosome number and chromosomal morphology of Mycetophylax conformis corresponded to those of previously studied populations, suggesting its karyotype stability.
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Affiliation(s)
- Danon Clemes Cardoso
- Departamento de Biodiversidade, Evolução e Meio Ambiente – Universidade Federal de Ouro Preto, Ouro Preto, Brazil
- Laboratório de Genética Evolutiva e de Populações – Universidade Federal de Ouro Preto, Ouro Preto, Brazil
| | - Tássia Tatiane Pontes Pereira
- Laboratório de Genética Evolutiva e de Populações – Universidade Federal de Ouro Preto, Ouro Preto, Brazil
- Programa de Pós-graduação em Ecologia – Universidade Federal de Viçosa, Viçosa, Brazil
| | - Alessandro Lick Cordeiro
- Laboratório de Genética Evolutiva e de Populações – Universidade Federal de Ouro Preto, Ouro Preto, Brazil
- Departamento de Genética – Universidade Federal do Paraná, Curitiba, Brazil
| | - Maykon Passos Cristiano
- Departamento de Biodiversidade, Evolução e Meio Ambiente – Universidade Federal de Ouro Preto, Ouro Preto, Brazil
- Laboratório de Genética Evolutiva e de Populações – Universidade Federal de Ouro Preto, Ouro Preto, Brazil
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Barros LAC, de Aguiar HJAC, Mariano CDSF, Andrade-Souza V, Costa MA, Delabie JHC, Pompolo SDG. Cytogenetic data on six leafcutter ants of the genus Acromyrmex Mayr, 1865 (Hymenoptera, Formicidae, Myrmicinae): insights into chromosome evolution and taxonomic implications. COMPARATIVE CYTOGENETICS 2016; 10:229-43. [PMID: 27551345 PMCID: PMC4977799 DOI: 10.3897/compcytogen.v10i2.7612] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 03/23/2016] [Indexed: 05/24/2023]
Abstract
Cytogenetic data for the genus Acromyrmex Mayr, 1865 are available, to date, for a few species from Brazil and Uruguay, which have uniform chromosome numbers (2n = 38). The recent cytogenetic data of Acromyrmex striatus (Roger, 1863), including its banding patterns, showed a distinct karyotype (2n = 22), similar to earlier studied Atta Fabricius, 1804 species. Karyological data are still scarce for the leafcutter ants and many gaps are still present for a proper understanding of this group. Therefore, this study aimed at increasing cytogenetic knowledge of the genus through the characterization of other six species: Acromyrmex balzani (Emery, 1890), Acromyrmex coronatus Fabricius, 1804, Acromyrmex disciger (Mayr, 1887), Acromyrmex echinatior (Forel, 1899), Acromyrmex niger (Smith, 1858) and Acromyrmex rugosus (Smith, 1858), all of which were collected in Minas Gerais - Brazil, except for Acromyrmex echinatior which was collected in Barro Colorado - Panama. The number and morphology of the chromosomes were studied and the following banding techniques were applied: C-banding, fluorochromes CMA3 and DAPI, as well as the detection of 45S rDNA using FISH technique. All the six species had the same chromosome number observed for already studied species, i.e. 2n = 38. Acromyrmex balzani had a different karyotype compared with other species mainly due to the first metacentric pair. The heterochromatin distribution also showed interspecific variation. Nevertheless, all the studied species had a pair of bands in the short arm of the first subtelocentric pair. The fluorochrome CMA3 visualized bands in the short arm of the first subtelocentric pair for all the six species, while Acromyrmex rugosus and Acromyrmex niger also demonstrated in the other chromosomes. The AT-rich regions with differential staining using DAPI were not observed. 45S ribosomal genes were identified by FISH in the short arm of the first subtelocentric pair in Acromyrmex coronatus, Acromyrmex disciger and Acromyrmex niger. The uniform chromosome number in the genus Acromyrmex (2n = 38) suggests that Acromyrmex striatus (2n = 22) should be transferred to a new genus. Other aspects of the chromosome evolution in ants are also discussed.
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Affiliation(s)
- Luísa Antônia Campos Barros
- Laboratório de Citogenética de Insetos, Departamento de Biologia Geral, Universidade Federal de Viçosa; Viçosa - MG, 36570-000, Brazil
- Universidade Federal do Amapá; Campus Binacional, Oiapoque - AP, 68980-000, Brazil
| | - Hilton Jeferson Alves Cardoso de Aguiar
- Laboratório de Citogenética de Insetos, Departamento de Biologia Geral, Universidade Federal de Viçosa; Viçosa - MG, 36570-000, Brazil
- Universidade Federal do Amapá; Campus Binacional, Oiapoque - AP, 68980-000, Brazil
| | - Cléa dos Santos Ferreira Mariano
- Laboratório de Mirmecologia, CEPEC/CEPLAC; Itabuna - BA, CP 7, 45600-000, Brazil
- Departamento de Ciências Biológicas, Universidade Estadual de Santa Cruz; Ilhéus - BA, 45650-000, Brazil
| | | | - Marco Antonio Costa
- Departamento de Ciências Biológicas, Universidade Estadual de Santa Cruz; Ilhéus - BA, 45650-000, Brazil
| | - Jacques Hubert Charles Delabie
- Laboratório de Mirmecologia, CEPEC/CEPLAC; Itabuna - BA, CP 7, 45600-000, Brazil
- Departamento de Ciências Agrárias e Ambientais, Universidade Estadual de Santa Cruz; Ilhéus - BA, 45650-000, Brazil
| | - Silvia das Graças Pompolo
- Laboratório de Citogenética de Insetos, Departamento de Biologia Geral, Universidade Federal de Viçosa; Viçosa - MG, 36570-000, Brazil
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