Cytogenetic Evidence Clarifies the Phylogeny of the Family Rhynchocyclidae (Aves: Passeriformes)

The phylogenetic position and taxonomic status of Rhynchocyclidae (Aves: Passeriformes) have been the subject of debate since their first description. In most models, Rhynchocyclidae represents a subfamily-level taxon placed within the Tyrant Flycatchers (Tyrannidae). Considering that this classification does not include cytotaxonomic characters, we tested the hypothesis that the chromosome organization of Rhynchocyclidae members differs from that of Tyrannidae. Hence, we selected two species, Tolmomyias sulphurescens, and Pitangus sulphuratus, representing Rhynchocyclidae and Tyrannidae, respectively. Results revealed a diploid number (2n) of 60 in T. sulphurescens and 2n = 80 in P. sulphuratus, indicating significant chromosomal differences. Chromosome mapping of Gallus gallus (GGA) and Taeniopygia guttata bacterial artificial chromosome (BAC) corresponding to chromosomes GGA1-28 (except 16) revealed that the genome evolution of T. sulphurescens involved extensive chromosome fusions of macrochromosomes and microchromosomes. On the other hand, P. sulphuratus retained the ancestral pattern of organization of macrochromosomes (except the centric fission involving GGA1) and microchromosomes. In conclusion, comparing our results with previous studies in Tyrant Flycatchers and allies indicates that P. sulphuratus has similar karyotypes to other Tyrannidae members. However, T. sulphurescens does not resemble the Tyrannidae family, reinforcing family status to the clade named Rhynchocyclidae.

Cytogenetic evidence supports Avena insularis being closely related to hexaploid oats.

Cytogenetic observations, phylogenetic studies and genome analysis using high-density genetic markers have suggested a tetraploid Avena species carrying the C and D genomes (formerly C and A) to be the donor of all hexaploid oats (AACCDD). However, controversy surrounds which of the three extant CCDD tetraploid species - A. insularis , A. maroccana and A. murphyi - is most closely related to hexaploid oats. The present work describes a comparative karyotype analysis of these three CCDD tetraploid species and two hexaploid species, A. sativa and A. byzantina . This involved the use of FISH with six simple sequence repeats (SSRs) with the motifs CT, AAC, AAG, ACG, ATC and ACT, two repeated ribosomal sequences, and C genome-specific repetitive DNA. The hybridization pattern of A. insularis with oligonucleotide (AC) 10 was also determined and compared with those previously published for A. sativa and A. byzantina . Significant differences in the 5S sites and SSR hybridization patterns of A. murphyi compared to the other CCDD species rule out its being directly involved in the origin of the hexaploids. In contrast, the repetitive and SSR hybridization patterns shown by the D genome chromosomes, and by most of the C genome chromosomes of A. maroccana and A. insularis , can be equated with the corresponding chromosomes of the hexaploids. Several chromosome hybridization signals seen for A. insularis , but not for A. maroccana , were shared with the hexaploid oats species, especially with A. byzantina . These diagnostic signals add weight to the idea that the extant A. insularis , or a direct ancestor of it, is the most closely related progenitor of hexaploid oats. The similarity of the chromosome hybridization patterns of the hexaploids and CCDD tetraploids was taken as being indicative of homology. A common chromosome nomenclature for CCDD species based on that of the hexaploid species is proposed.

Cytogenetic Evidence for Sex Chromosomes and Karyotype Evolution in Anguimorphan Lizards

Anguimorphan lizards are a morphologically variable group of squamate reptiles with a wide geographical distribution. In spite of their importance, they have been cytogenetically understudied. Here, we present the results of the cytogenetic examination of 23 species from five anguimorphan families (Anguidae, Helodermatidae, Shinisauridae, Varanidae and Xenosauridae). We applied both conventional (Giemsa staining and C-banding) and molecular cytogenetic methods (fluorescence in situ hybridization with probes for the telomeric motifs and rDNA loci, comparative genome hybridization), intending to describe the karyotypes of previously unstudied species, to uncover the sex determination mode, and to reveal the distribution of variability in cytogenetic characteristics among anguimorphan lizards. We documented that karyotypes are generally quite variable across anguimorphan lineages, with anguids being the most varying. However, the derived chromosome number of 2n = 40 exhibits a notable long-term evolutionary stasis in monitors. Differentiated ZZ/ZW sex chromosomes were documented in monitors and helodermatids, as well as in the anguids Abronia lythrochila, and preliminary also in Celestus warreni and Gerrhonotus liocephalus. Several other anguimorphan species have likely poorly differentiated sex chromosomes, which cannot be detected by the applied cytogenetic methods, although the presence of environmental sex determination cannot be excluded. In addition, we uncovered a rare case of spontaneous triploidy in a fully grown Varanus primordius.

Cytogenetic evidence for a new genus of Triticeae (Poaceae) endemic to the Iberian Peninsula: description and comparison with related genera

Thinopyrum curvifolium, a halo-gypsophyte endemic to the Iberian Peninsula, has an uncertain cytogenetic composition. Moreover, it is often confused with other species of the genus due to morphological resemblance. In this study, we analyse its genomic composition using in situ hybridization and study lodicule morphology and foliar anatomy, to identify distinguishing traits of the species in comparison with the remaining representatives of Thinopyrum in the Iberian Peninsula and the Balearic Islands. In situ hybridization data support the genomic formula 2n = 4x = 28, EbP. Lodicule morphology and foliar anatomy proved helpful in characterizing the species. These new discoveries, in addition to the macromorphological data compiled, support the contentions that (1) T. curvifolium should be segregated from Thinopyrum sensu D.R.Dewey, and (2) a new cytogenetically based genus should be proposed in order to classify the species properly according to the cytogenetically based criteria traditionally proposed for the classification of Triticeae. Therefore, we hereby propose a new genus named Pauneroa gen. nov., including the new nomenclatural combination Pauneroa curvifolia comb. nov., and provide a detailed iconography of the plant, macroscopically comparing the genus with closely related genera.

Benign inflammatory myofibroblastic tumour of the nose: a rare case report

Inflammatory myofibroblastic tumor (IMT) of the head and neck region are rare and benign and of unknown etiology. They mimic as malignant lesions both clinically and radiologically. It encompasses a spectrum of myofibroblastic proliferation along with varying amount of inflammatory infiltrate. Recently, the concept of this lesion being reactive has been challenged based on the clinical demonstration of recurrences and metastasis and cytogenetic evidence of acquired clonal chromosomal abnormalities. Here we report a case of a 16 year old male who presented with a swelling on the nasal dorsum for 6 months. MRI and FNAC revealed a spindle cell neoplasm. The swelling was resected completely under general anaesthesia. Histopathology with immunohistochemistry proved it to be a benign inflammatory myofibrobalstic tumour. Complete surgical resection is the best treatment modality for IMT.

New data on karyotypes of lace bugs (Tingidae, Cimicomorpha, Hemiptera) with analysis of the 18S rDNA clusters distribution

The karyotypes of 10 species from 9 genera of the family Tingidae (Hemiptera, Heteroptera, Cimicomorpha) are described and illustrated for the first time. These species are: Agrammaatricapillum (Spinola, 1837), Catoplatuscarthusianus (Goeze, 1778), Dictylaplatyoma (Fieber, 1861), Lasiacanthahermani Vásárhelyi, 1977, Oncochilasimplex (Herrich-Schaeffer, 1830), Tingis (Neolasiotropis) pilosa Hummel, 1825, and T. (Tropidocheila) reticulata Herrich-Schaeffer, 1835, all with 2n = 12A + XY, as well as Acalyptamarginata (Wolff, 1804), Derephysia (Paraderephysia) longispina Golub, 1974, and Dictyonotastrichnocera Fieber, 1844, all with 2n = 12A + X(0). Moreover, genera Catoplatus Spinola, 1837, Derephysia Spinola, 1837, and Oncochila (Herrich-Schaeffer, 1830) were explored cytogenetically for the first time. Much as all other hitherto studied lace bugs, the species studied here have 12 autosomes but differ in their sex chromosome systems. The ribosomal clusters were localized on male meiotic cells of all ten species already mentioned and, additionally, in Acalyptacarinata Panzer, 1806 known to have 2n = 12A + X (Grozeva and Nokkala 2001) by fluorescence in situ hybridization (FISH) using a PCR amplified 18S rDNA fragment as a probe. In all cases, rDNA loci were located interstitially on a pair of autosomes. Furthermore, two species possessed some additional rDNA clusters. Thus, Acalyptamarginata showed clearly defined interstitial clusters on one more pair of autosomes, whereas Derephysialongispina had a terminal cluster on the X-chromosome. FISH performed with the telomeric (TTAGG)n probe did not reveal labelling in chromosomes of any species studied. Hence, the results obtained provide additional evidence for the karyotype conservatism, at least regarding the number of autosomes, for variation in chromosomal distribution of rDNA loci between species and for the lack of the ancestral insect telomeric sequence TTAGG in lace bugs. Preliminary taxonomic comments are made basing on some cytogenetic evidence.