Diploid Chromosome Research Articles

A checklist of chromosome numbers and a review of karyotype variation in Odonata of the world.

The ancient insect order Odonata is divided into three suborders: Anisoptera and Zygoptera with approximately 3000 species worldwide each, and Anisozygoptera with only four extant species in the relict family Epiophlebiidae. An updated list of Odonata species studied regarding chromosome number, sex chromosome mechanism and the occurrence of m-chromosomes (= microchromosomes) is given. Karyotypes of 607 species (198 genera, 23 families), covering approximately 10% of described species, are reported: 423 species (125 genera, 8 families) of the Anisoptera, 184 species (72 genera, 14 families) of the Zygoptera, and one species of the Anisozygoptera. Among the Odonata, sex determination mechanisms in males can be of X(0), XY and X1X2Y types, and diploid chromosome numbers can vary from 6 to 41, with a clear mode at 2n = 25(60%) and two more local modes at 2n = 27(21%) and 2n = 23(13%). The karyotype 2n = 25(24A + X) is found in each of the three suborders and is the most typical (modal) in many families, including the best-covered Libellulidae, Corduliidae (Anisoptera), Lestidae, Calopterygidae, and Platycnemididae (Zygoptera). This chromosome set is considered ancestral for the Odonata in general. Chromosome rearrangements, among which fusions and fissions most likely predominated, led to independent origins of similar karyotypes within different phylogenetic lineages of the order. The karyotype 2n = 27(26A + X) prevails in Aeshnidae and Coenagrionidae, whereas the karyotype 2n = 23(22A + X) is modal in Gomphidae and Chlorocyphidae, in both pairs of families one being from the Anisoptera while the other from the Zygoptera.

Comparative analysis of the morphology, karyotypes and biochemical composition of muscle in Siniperca chuatsi, Siniperca scherzeri and the F1 hybrid (S. chuatsi ♀ × S. scherzeri ♂)

Combining morphological comparison with karyotyping can make a more accurate and comprehensive study of mandarin fish (Siniperca spp.) and hybrid progenies.In recent years, the domestication of hybrid mandarin fish has become a hot spot in China, and it is essential to evaluate the nutritional value of the fish after food conversion. In this study, the F1 hybrid (S. chuatsi ♀ × S. scherzeri♂) were fed with artificial feed for five months. Afterwards, we studied the morphology, karyotypes, and biochemical composition of muscle in the F1 hybrid and its parents. The morphological results showed that total length and body height of the F1 hybrid appear to derive more from S. chuatsi than S. scherzeri. The DNA ploidy and karyotype results indicated that the F1 hybrid have a diploid chromosome number (2n = 48) and the same karyotypes (2n = 4sm + 14th+30t, NF = 52) with its parents, suggesting that the chromosome of the mandarin fish has convergence in the process of evolution. The results of biochemical composition of muscle showed that there were no significant difference in other nutritional indicators (P > 0.05), except the Gly (glycine) content of the F1 hybrid was significantly higher than that of S. chuatsi (P < 0.05) under the experimental feeding regime, suggesting that the nutritional value of the F1 hybrid with artificial feeding culture is also higher. The study is expected to provide a reference for further research on the domestication, classification, chromosomes, and nutritional requirements of mandarin fish.

Karyotypes of Five Spider Species from Mediterranean and Central Regions of Turkey

Here we present the first data on karyotype structures in five spider species belonging to the families Agelenidae, Salticidae and Thomisidae collected from Mediterranean and central regions of Turkey. An air-drying method was used to obtain mitotic and meiotic chromosomes. The karyotype characteristics including diploid chromosome number and sex chromosome systems were in Salticidae: Euophrys frontalis (Walckenaer, 1802) and Attulus distinguendus (Simon, 1868), 2n♂ = 28, X1X20; Thomisidae: Xysticus lanio C. L. Koch, 1835 and Xysticus ferrugineus Menge, 1876, 2n♂ = 23, X0; Agelenidae: Agelena orientalis C. L. Koch, 1837, 2n♂ = 42, X1X20. Sex chromosomes were identified tentatively. All species contained monoarmed chromosomes and there was a gradual decrease in their total lengths.

Somatic embryogenesis and plant regeneration in Ferula jaeschkeana Vatke: a threatened medicinal herb

An efficient in vitro propagation protocol for an important medicinal endangered herb Ferula jaeschkeana has been developed through somatic embryogenesis. 12 week old friable calli were derived from petiole explants on a medium supplemented with 2.0 mgl−1 2,4-D and 1.0 mgl−1 Kn and used as mother source for somatic embryogenesis. Different auxins (2,4-D, IBA, IAA and NAA) in different concentrations (0.2–4.0 mgl−1) was used to produce embryogenic callus. Eighty four percent calli produced globular embryos on a medium supplemented with 4.0 mgl−1 2,4-D. The globular embryo then mature on culture medium (Control) or supplemented with different addictives (auxin, proline and ABA), maturation was significantly affected by ABA, proline and number of subcultures with maximum number of mature embryo (32.1 ± 0.2) was formed on medium fortified with 2.0 mgl−1 proline. Mature embryos had two well-developed cotyledons and an elongated hypocotyl root axis. 78% of these embryos were transformed into plantlets when placed in culture medium fortified with 0.2 + 0.01 + 0.05 mgl−1 (BAP:IBA:GA3) respectively. Regenerated plants were hardened in vermiculite with a 23% survival rate. The regenerated plants showed normal diploid chromosome number (2n = 22) and leaf morphology was comparable to in vivo plant.

Establishment of Conditions for Long-Term Maintenance of Primary Embryonic Cell Cultures from Olive Flounder Paralichthys olivaceus.

Primary cell culture is a sufficient method frequently used to study the cellular properties and mechanisms of isolated cells in a controlled environment. In this study, an embryonic cell line (FGBC8) derived from the blastula stages of embryos of olive flounder Paralichthys olivaceus was developed. Furthermore, conditions for optimal long-term maintenance of this primary embryonic cell culture were investigated. Morphologically, FGBC8 cells were composed primarily of epithelial-like cells. FGBC8 cells were subcultured for >160 passages over ~830 days. The doubling time of FGBC8 cells was 73.8 h, and the modal diploid chromosome number was 48. FGBC8 cells transfected with green fluorescence protein (GFP)-expression plasmid exhibited a strong signal 48 h after transfection. Consequently, we demonstrated that fish serum is a crucial supplement for the long-term survival and maintenance of comparable morphology in these primary embryonic cells. Our results can be used as a guide for primary embryonic cell cultures for other fish species and may be useful for cell biotechnological applications.

The Karyotype of the Pacific Lion-Paw Scallop Nodipecten subnodosus (Sowerby, 1835)

The lion-paw scallop Nodipecten subnodosus is a commercially important Pectinidae species. Basic research is being carried for its genetic improvement and breeding. In this study, trochophore larvae of N. subnodosus scallop were used to obtain metaphase spreads and to describe the karyotype. The diploid chromosome number (2n) of this species is 38, as the only other species of the same genus Nodipecten nodosus, and in almost all the species studied so far in the Pectinidae group. The relative length of the largest chromosome is 6.92 and for the smallest is 4.22. Based on the constructed karyo-ideogram, three distinctive chromosomes with the longest size (1–3) are in the area of submetacentric (sm) and subtelocentric (st) chromosomes, whereas the others in the karyo-ideogram are difficult to be distinguished between metacentric (m), submetacentric (sm), or m-sm. Additional estimates of the centromeric index values indicated that the karyotype consists of 3 m, 8 m-sm, 6 sm, 1 sm-st, and 1 st chromosome pairs. The number of arms is 38. There are polymorphisms in the presence/absence of secondary constrictions. In one karyotype, the constrictions were in the two homologous chromosomes of one pair, whereas in other karyotypes, there were pairs with only one chromosome bearing the constriction, and other karyotypes had none. The chromosome morphology described here for the species N. subnodosus can serve as a basis for comparisons between scallops of the Nodipecten genus, which is composed of eight species.

First cytogenetic information for five Nilotic elephantfishes and a problem of ancestral karyotype of the family Mormyridae (Osteoglossiformes).

The elephantfish family Mormyridae is the most diverse lineage of the primitive teleostean clade Osteoglossomorpha distributed in inland waters of all continents except Antarctica and Europe. The family Mormyridae is endemic to Africa and includes 22 genera and almost 230 species. The evolutionary radiation of mormyrids most probably should be attributed to their capability of both generating and receiving weak electric signals. Up-to-date cytogenetic studies have revealed substantial karyotype differentiation among the nine investigated elephantfish species and genera (a single species studied per each genus). In the present study, karyotypes of five species representing five mormyrid genera (four unexplored ones) collected from the White Nile system in southwestern Ethiopia are described for the first time. The results show substantial variety of the diploid chromosome and fundamental numbers: 2n = 48 and FN = 54 in Brevimyrus niger (Günther, 1866), 2n = 50 and FN = 72 in Cyphomyrus petherici (Boulenger, 1898), 2n = 50 and FN = 78 in Hippopotamyrus pictus (Marcusen, 1864), 2n = 50 and FN = 76 in Marcusenius cyprinoides (Linnaeus, 1758), 2n = 52 and FN = 52 in Mormyrops anguilloides (Linnaeus, 1758). Karyotype structure in the latter species seems to be close to the ancestral condition for the family. This hypothesis is discussed in the light of available data on karyotype diversity and phylogeny of mormyrids.

Mode and Tempo of Microsatellite Evolution across 300 Million Years of Insect Evolution.

Microsatellites are short, repetitive DNA sequences that can rapidly expand and contract due to slippage during DNA replication. Despite their impacts on transcription, genome structure, and disease, relatively little is known about the evolutionary dynamics of these short sequences across long evolutionary periods. To address this gap in our knowledge, we performed comparative analyses of 304 available insect genomes. We investigated the impact of sequence assembly methods and assembly quality on the inference of microsatellite content, and we explored the influence of chromosome type and number on the tempo and mode of microsatellite evolution across one of the most speciose clades on the planet. Diploid chromosome number had no impact on the rate of microsatellite evolution or the amount of microsatellite content in genomes. We found that centromere type (holocentric or monocentric) is not associated with a difference in the amount of microsatellite content; however, in those species with monocentric chromosomes, microsatellite content tends to evolve faster than in species with holocentric chromosomes.

Comparative FISH-mapping of TTAGG telomeric sequences to the chromosomes of leafcutter ants (Formicidae, Myrmicinae): is the insect canonical sequence conserved?

Telomeric sequences are conserved across species. The most common sequence reported among insects is (TTAGG)n, but its universal occurrence is not a consensus because other canonical motifs have been reported. In the present study, we used fluorescence in situ hybridization (FISH) using telomeric probes with (TTAGG)6 repeats to describe the telomere composition of leafcutter ants. We performed the molecular cytogenetic characterization of six Acromyrmex Mayr, 1865 and one Atta Fabricius, 1804 species (Acromyrmex ambiguus (Emery, 1888), Ac. crassispinus (Forel, 1909), Ac. lundii (Guérin-Mèneville, 1838), Ac. nigrosetosus (Forel, 1908), Ac. rugosus (Smith, 1858), Ac. subterraneus subterraneus (Forel, 1893), and Atta sexdens (Linnaeus, 1758)) and described it using a karyomorphometric approach on their chromosomes. The diploid chromosome number 2n = 38 was found in all Acromyrmex species, and the karyotypic formulas were as follows: Ac. ambiguus 2K = 14M + 12SM + 8ST + 4A, Ac. crassispinus 2K = 12M + 20SM + 4ST + 2A, Ac. lundii 2K = 10M + 14SM + 10ST + 4A, Ac. nigrosetosus 2K = 12M + 14SM + 10ST + 2A, and Ac. subterraneus subterraneus 2K = 14M + 18SM + 4ST + 2A. The exact karyotypic formula was not established for Ac. rugosus. FISH analyses revealed the telomeric regions in all the chromosomes of the species studied in the present work were marked by the (TTAGG)6 sequence. These results reinforce the premise that Formicidae presents high homology between their genera for the presence of the canonical sequence (TTAGG)n.

The somatic chromosomes of F1 hybrid male deer (Hyelaphus porcinus × Axis axis) by comparative banding techniques

The chromosome analyses of F1 hybrid male deer from the cross of Hyelaphus porcinus male and Axis axis female have been presented. Chromosomes were prepared from T-lymphocyte by conventional staining and GTC-banding techniques. The results showed that the diploid chromosome number of F1 hybrid male deer was 2n = 67, fundamental number was 70. The special karyotype consisted of 2 large metacentric, 1 large submetacentric, 13 large telocentric, 18 medium telocentric and 31 small telocentric chromosomes. The X-chromosome was large telocentric chromosome and Y-chromosome was small acrocentric chromosome. The amount of GTG-banding pattern on a set of haploid number (n) in the hybrid were 261 bands. The GTG-banding comparison of hybrid deer and the parents has been shown with the deduced karyotype formula as: 2n (67) = Lm2 + Lsm1 + Lt13 + Mt18 + St31 + sex chromosomes

Evidence of Interspecific Chromosomal Diversification in Rainbowfishes (Melanotaeniidae, Teleostei).

Rainbowfishes (Melanotaeniidae) are the largest monophyletic group of freshwater fishes occurring in Australia and New Guinea, with 112 species currently recognised. Despite their high taxonomic diversity, rainbowfishes remain poorly studied from a cytogenetic perspective. Using conventional (Giemsa staining, C banding, chromomycin A3 staining) and molecular (fluorescence in situ hybridisation with ribosomal DNA (rDNA) and telomeric probes) cytogenetic protocols, karyotypes and associated chromosomal characteristics of five species were examined. We covered all major lineages of this group, namely, Running River rainbowfish Melanotaenia sp., red rainbowfish Glossolepis incisus, threadfin rainbowfish Iriatherina werneri, ornate rainbowfish Rhadinocentrus ornatus, and Cairns rainbowfish Cairnsichthys rhombosomoides. All species had conserved diploid chromosome numbers 2n = 48, but karyotypes differed among species; while Melanotaenia sp., G. incisus, and I. werneri possessed karyotypes composed of exclusively subtelo/acrocentric chromosomes, the karyotype of R. ornatus displayed six pairs of submetacentric and 18 pairs of subtelo/acrocentric chromosomes, while C. rhombosomoides possessed a karyotype composed of four pairs of submetacentric and 20 pairs of subtelo/acrocentric chromosomes. No heteromorphic sex chromosomes were detected using conventional cytogenetic techniques. Our data indicate a conserved 2n in Melanotaeniidae, but morphologically variable karyotypes, rDNA sites, and heterochromatin distributions. Differences were observed especially in taxonomically divergent species, suggesting interspecies chromosome rearrangements.

Chromosomal Evolution in the Phylogenetic Context: A Remarkable Karyotype Reorganization in Neotropical Parrot Myiopsitta monachus (Psittacidae).

Myiopsitta monachus is a small Neotropical parrot (Psittaciformes: Arini Tribe) from subtropical and temperate regions of South America. It has a diploid chromosome number 2n = 48, different from other members of the Arini Tribe that have usually 70 chromosomes. The species has the lowest 2n within the Arini Tribe. In this study, we combined comparative chromosome painting with probes generated from chromosomes of Gallus gallus and Leucopternis albicollis, and FISH with bacterial artificial chromosomes (BACs) selected from the genome library of G. gallus with the aim to shed light on the dynamics of genome reorganization in M. monachus in the phylogenetic context. The homology maps showed a great number of fissions in macrochromosomes, and many fusions between microchromosomes and fragments of macrochromosomes. Our phylogenetic analysis by Maximum Parsimony agree with molecular data, placing M. monachus in a basal position within the Arini Tribe, together with Amazona aestiva (short tailed species). In M. monachus many chromosome rearrangements were found to represent autopomorphic characters, indicating that after this species split as an independent branch, an intensive karyotype reorganization took place. In addition, our results show that M. monachus probes generated by flow cytometry provide novel cytogenetic tools for the detection of avian chromosome rearrangements, since this species presents breakpoints that have not been described in other species.

Unusual chromosome polymorphism and heterochromatin variation in the Argentinean population of the necrophagous fly Lucilia sericata (Diptera: Calliphoridae), comparison with other populations and evolutionary aspects

Heterochromatin may vary qualitatively, quantitatively, and in its location both in and between species. There were differences recorded in sex chromosomes, satellite sizes and location of C-bands in specimens of Lucilia sericata (Meigen, 1826) from three localities in the Buenos Aires region, Argentina (Bernal, Castelar, and Buenos Aires City). Mitotic analyses revealed the same diploid chromosome number of 2n = 10 + XY / XX (male / female) and the same size, morphology, and C-banding patterns on their autosomes. However, there are different morphotypes of X and Y chromosomes with a distinctive heterochromatin content in both arms. Four morphotypes of X (X1, X2, X3, and X4) and three of Y (Y1, Y2, and Y3) were recorded. The X metacentric and Y subtelocentric chromosomes were identified based on their very large and small sizes, respectively, and both had large heterochromatic blocks. These intraspecific differences are mainly due to quantitative variations in non-coding repetitive sequences located in the arms of both X and Y sex chromosomes. The specimens were very polymorphic both between and within the three localities sampled. Cytogenetic studies on specimens of L. sericata from the Nearctic, Palaearctic and Ethiopian regions also report differences in the morphology of the sex chromosomes and their C-banding patterns, some of which may have evolved independently. Our cytogenetic observations on L. sericata indicate that the accumulation of heterochromatin in the genome could be involved in chromosomal divergence and karyotype evolution of this species, as demonstrated in other Diptera. The polymorphic sex chromosomes are therefore important for understanding the evolution within species as well as speciation.

Chemical composition, antimicrobial activity and chromosome number of Hertia cheirifolia L. from Algeria

Abstract The aims of this work are to investigate the chemical composition, the antibacterial activity of the essential oil and the chromosome numbers of two populations of Hertia cheirifolia. The samples were collected in the flowering stage, in eastern Algeria locality. The aerial parts of H. cheirifolia were submitted to a hydro-distillation. GC and GC / MS analysed the chemical compositions of the obtained essential oils. The antibacterial activity of essential oils was evaluated using the disks diffusion method against ten bacterial strains. For karyotypic analysis, the squashing method is used. Fifty-eight compounds representing 98.93% of the total oil were identified in H. cheirifolia. The chemical composition is dominated by the presence of major products, α-pinene (48.49 - 53.85%) and Germacrene-D (2.64 - 12.66%). Two distinct chemical breeds were identified, the α-pinene-spathulenol of Batna population, and the α-pinene-germacrene-D of Setif population. The essential oil of H. cheirifolia has a moderate activity against bacteria tested. In contrast, the strains E. coli ATCC 25922, P. syringae ATCC 53543 and E. fecalis ATCC 49452 are resistant to H. cheirifolia essential oils. The observations of root cells meristematic at metaphase of H. cheirifolia gave a diploid chromosome number 2n = 2x = 20, with a basic chromosome number (x= 10).

Studies on gene action expression of yield and yield related traits of brinjal (Solanum melongena L.)

Brinjal (Solanum melongena L.) is one of the mostimportant solanaceous vegetable crop of sub-tropics andtropics having diploid chromosome number 2n=2x=24.It is a versatile crop adapted to different agro-climaticregions and can be grown throughout the year. India isregarded as the primary centre of origin/diversity of brinjal(Bhaduri 1951 and Vavilov 1931). In India, brinjaloccupies an area of 6.69 lakh hectare with estimatedannual production of 12.4 million tonnes in 2016-17. InUttar Pradesh, brinjal is being cultivated on an area of7.83 thousand ha with annual production of 0.269 milliontones (NHB 2016-17). Brinjal has Ayurvedic medicinalproperties. It has also been recommended as an excellentremedy for liver complaints and diabetic patients (Tiwariet al. 2009). White brinjal is good for diabetic patients.Being rich in fiber, potassium, vitamin B-6 andphytonutrients like flavonoids

Molecular Cytogenetic Characterization of the Sicilian Endemic Pond Turtle Emys trinacris and the Yellow-Bellied Slider Trachemys scripta scripta (Testudines, Emydidae).

Turtles, a speciose group consisting of more than 300 species, demonstrate karyotypes with diploid chromosome numbers ranging from 2n = 26 to 2n = 68. However, cytogenetic analyses have been conducted only to 1/3rd of the turtle species, often limited to conventional staining methods. In order to expand our knowledge of the karyotype evolution in turtles, we examined the topology of the (TTAGGG)n telomeric repeats and the rDNA loci by fluorescence in situ hybridization (FISH) on the karyotypes of two emydids: the Sicilian pond turtle, Emys trinacris, and the yellow-bellied slider, Trachemys scripta scripta (family Emydidae). Furthermore, AT-rich and GC-rich chromosome regions were detected by DAPI and CMA3 stains, respectively. The cytogenetic analysis revealed that telomeric sequences are restricted to the terminal ends of all chromosomes and the rDNA loci are localized in one pair of microchromosomes in both species. The karyotype of the Sicilian endemic E. trinacris with diploid number 2n = 50, consisting of 13 pairs of macrochromosomes and 12 pairs of microchromosomes, is presented here for first time. Our comparative examination revealed similar cytogenetic features in Emys trinacris and the closely related E. orbicularis, as well as to other previously studied emydid species, demonstrating a low rate of karyotype evolution, as chromosomal rearrangements are rather infrequent in this group of turtles.

Karyotype analysis and nucleolar organizer regions (NORs) of Sundaic yellow catfish, Hemibagrus capitulum (Siluriformes, Siluridae) in Thailand

This is the first report on karyo-morphological details and characteristic of nucleolar organizer regions (NORs) of Sundaic yellow catfish, Hemibagrus capitulum (Siluriformes, Siluridae), from Sirindhorn Peat Swamp Forest, Narathiwat Province, Thailand.The mitotic chromosome preparations were prepared from kidney cells of ten male and eight female specimens. Conventional staining and Ag-NOR banding techniques were applied to stain the chromosomes. The results showed that the diploid chromosome number of H. capitulum was 2n = 56 and the fundamental number of both sexes was 108. The karyotype consists of 2 large metacentric, 8 large submetacentric, 2 large acrocentric, 18 medium metacentric, 12 medium submetacentric, 6 medium acrocentric, 4 medium telocentric, and 4 small metacentric chromosomes. None of strange size chromosomes related to sex was found. In addition, the telomeric NORs were clearly observed in the short arm of the submetacentric chromosome pair 16. The karyotype formula for H. capitulum is as follows: 2n = 56 = L2m + L8sm + L2a + M18m + M12sm + M6a + M4t + S4m.

Reduced chromatin accessibility underlies gene expression differences in homologous chromosome arms of diploid Aegilops tauschii and hexaploid wheat.

BackgroundPolyploidy is centrally important in the evolution and domestication of plants because it leads to major genomic changes, such as altered patterns of gene expression, which are thought to underlie the emergence of new traits. Despite the common occurrence of these globally altered patterns of gene expression in polyploids, the mechanisms involved are not well understood.ResultsUsing a precisely defined framework of highly conserved syntenic genes on hexaploid wheat chromosome 3DL and its progenitor 3 L chromosome arm of diploid Aegilops tauschii, we show that 70% of these gene pairs exhibited proportionately reduced gene expression, in which expression in the hexaploid context of the 3DL genes was ∼40% of the levels observed in diploid Ae tauschii. Several genes showed elevated expression during the later stages of grain development in wheat compared with Ae tauschii. Gene sequence and methylation differences probably accounted for only a few cases of differences in gene expression. In contrast, chromosome-wide patterns of reduced chromatin accessibility of genes in the hexaploid chromosome arm compared with its diploid progenitor were correlated with both reduced gene expression and the imposition of new patterns of gene expression.ConclusionsOur pilot-scale analyses show that chromatin compaction may orchestrate reduced gene expression levels in the hexaploid chromosome arm of wheat compared to its diploid progenitor chromosome arm.

Continuous Cell Lines from the European Biting Midge Culicoides nubeculosus (Meigen, 1830).

Culicoides biting midges (Diptera: Ceratopogonidae) transmit arboviruses of veterinary or medical importance, including bluetongue virus (BTV) and Schmallenberg virus, as well as causing severe irritation to livestock and humans. Arthropod cell lines are essential laboratory research tools for the isolation and propagation of vector-borne pathogens and the investigation of host-vector-pathogen interactions. Here we report the establishment of two continuous cell lines, CNE/LULS44 and CNE/LULS47, from embryos of Culicoides nubeculosus, a midge distributed throughout the Western Palearctic region. Species origin of the cultured cells was confirmed by polymerase chain reaction (PCR) amplification and sequencing of a fragment of the cytochrome oxidase 1 gene, and the absence of bacterial contamination was confirmed by bacterial 16S rRNA PCR. Both lines have been successfully cryopreserved and resuscitated. The majority of cells examined in both lines had the expected diploid chromosome number of 2n = 6. Transmission electron microscopy of CNE/LULS44 cells revealed the presence of large mitochondria within cells of a diverse population, while arrays of virus-like particles were not seen. CNE/LULS44 cells supported replication of a strain of BTV serotype 1, but not of a strain of serotype 26 which is not known to be insect-transmitted. These new cell lines will expand the scope of research on Culicoides-borne pathogens.

Cytogenetic and Molecular Characterization of Three Mimetic Species of the Genus Alagoasa Bechyné 1955 (Coleoptera: Alticinae) from the Neotropical Region

Coleoptera is a mega-diverse order, but only about 1% of its species have been analyzed cytogenetically. In this order, the subfamily Alticinae presents many identification problems, mainly due to the occurrence of mimicry. The objective of this work was to cytogenetically characterize 3 very similar species of the genus Alagoasa (A. pantina, A.areata, and A.scissa). We used classical and molecular cytogenetic as well as molecular genetic techniques. All 3 species showed a diploid chromosome number of 2n = 22 (20+X+y), but differences in the morphology of the chromosomes. All had a meiotic formula of 2n = 10II+X+y and an X+y sex determination system with giant, fully asynaptic sex chromosomes, concordant characteristics observed in the subtribe Oedionychina. FISH demonstrated the presence of 18S and 5S rDNA clusters in 1 pair of autosomes, syntenic and colocalizing in the 3 analyzed species. However, in A. areata, heteromorphism between the cistrons was observed. The telomeric (TTAGG)_n probe showed signals in all 3 species, with proximal signals in the X and dispersed signals in the y chromosome of A. areata, and 2 proximal signals in the X chromosome of A. scissa. Molecular analysis of the COI gene indicated that they are 3 distinct species, corroborating the observed cytogenetic characteristics.