First Report on Karyotypic, Morphometric and Meiotic Analysis of a Predatory Bombardier Beetle Pherosophus catoirai (Coleoptera: Carabidae) from Jammu region of Outer Himalayas, India

Chromosomal studies and manual karyotyping are the aged techniques for determining the identity of a species on evolutionary scale; however, these techniques are simple, reliable and inexpensive to authenticate the existence of a particular species. In the present work, the chromosome complement and meiotic processes of a predatory bombardier beetle Pherosophus catoirai were investigated. This species presented 2n=35 as diploid chromosome number and the chromosomal formula was found to be 12m+8sm+12st+X0. Sex mechanism was X0 type with metacentric X chromosome. Y chromosome was absent in this species. Karyotype revealed small chromosomes except X chromosome which is found to be largest in the spermatogonial metaphase stage. Meiotic stages were pachytene, diplotene, diakinesis and metaphase-I. Present study may find importance to analyse evolution of chromosomes in order Coleoptera particularly in family Carabidae.

Derived karyotypes in two elephantfish genera (Hyperopisus and Pollimyrus): lowest chromosome number in the family Mormyridae (Osteoglossiformes)

The African weakly electric elephantfish family Mormyridae comprises 22 genera and almost 230 species. Up-to-date cytogenetic information was available for 17 species representing 14 genera. Here we report chromosome number and morphology in Hyperopisus bebe (Lacepède, 1803) and Pollimyrus isidori (Valenciennes, 1847) collected from the White Nile system in southwestern Ethiopia. Both taxa displayed the diploid chromosome number 2n = 40, but they differed in fundamental numbers: FN = 66 in H. bebe and FN = 72 in P. isidori; previously the same diploid chromosome number 2n = 40 was reported in an undescribed species of Pollimyrus Taverne, 1971 (FN = 42) from the same region. Our results demonstrate that not only pericentric inversions, but fusions also played a substantial role in the evolution of the mormyrid karyotype structure. If the hypothesis that the karyotype structure with 2n = 50–52 and prevalence of the uni-armed chromosomes close to the ancestral condition for the family Mormyridae is correct, the most derived karyotype structures are found in the Mormyrus Linnaeus, 1758 species with 2n = 50 and the highest number of bi-armed elements in their compliments compared to all other mormyrids and in Pollimyrus isidori with the highest number of bi-armed elements among the mormyrids with 2n = 40.

A karyotype study in two fish species belonging to Genus Neolissochilus found in Meghalaya, India

The karyomorphological study of two species of Mahseer belonging to the genus Neolissochilus, namely Neolissochilus hexagonolepis and N. hexastichus were carried out. The study revealed the basic chromosome number in both the Masheer species was observed to be 100. However, the karyotype formula number varied among the species. N. hexagonolepis had a diploid chromosome number of 42 metacentric (m), 20 submetacentric (sm), 8 subtelocentric (st) and 30 telocentric (t) and N. hexastichus had a karyotypic formula of 32 metacentric (m), 22 submetacentric (sm), 4 subtelocentric (st) and 42 telocentric (t). This finding removed taxonomic confusion due to the differences in the chromosome number, the morphology of the chromosomes and chromosome formula between the two fish species of the genus and helped in distinctive and unblemished identification of the two species belonging to the genus Neolissochilus from Meghalaya, though they have a morphological similarity.

A comparative chromosome study on five Minnow fishes (Cyprinidae, Cypriniformes) in Thailand

The cytogenetic comparisons of five Minnow species from Thailand were presented here, i.e., Devario regina, D. laoensis, Rasbora paviana, R. aurotaenia and Esomus metalicus. The mitotic chromosomes were prepared directly from renal cells. Conventional staining and Ag-NOR banding techniques were applied to stain the chromosomes. The results revealed that all Minnow fishes studied possessed the same diploid chromosome number (2n) as 50 chromosomes. The fundamental numbers (NF) of D. laoensis, D. regina, R. paviana, R. aurotaenia and E. metalicus are 100, 100, 98, 98, and 98 respectively. Their karyotypes composing of metacentrics-submetacentrics-acrocentrics-telocentrics were as follows: 6-12-32-0 in D. regina, 6-10-34-0 in D. laoensis, 8-16-24-2 in R. paviana, 8-16-24-2 in R. aurotaenia and 8-10-30-2 in E. metalicus. The Ag-NOR banding technique provides the nucleolar organizer regions (NORs) at subtelomeric region of the short arm chromosome in the a submetacentric or acrocentric chromosomes that are located differently in the different chromosome pairs among species.

Establishment of Cell Lines from Slender Walking Catfish Clarias nieuhofii (Valenciennes, 1840)

The slender walking catfish (Clarias nieuhofii Valenciennes, 1840) is a freshwater fish found in the ecosystems within the peat swamp forests of South-East Asian countries, including Thailand. In this study, a new testis fibroblast-like (FLT) and ovary epithelial-like (ELO) cells derived from C. nieuhofii (Valenciennes, 1840) was established. The optimal number of both cells was determined, and the optimal starting concentration of both cells is approximately 105 cellsžml-1. The FLT and ELO can grow best at 28 °C in DMEM supplemented with 20, 15, and 10 % fetal bovine serum (FBS). Chromosome analysis revealed that the typical diploid chromosome number was 66 (2n) in C. nieuhofii (Valenciennes, 1840). In both males and females, the elementary number of chromosomes (NF; the number of chromosome arms) was 98. No heteromorphic chromosome was observed. Four types of chromosomes were found in this species, including 14 metacentric, 20 submetacentric, 2 acrocentric, and 30 telocentric chromosomes. The FLT and ELO cells were maintained up to 6 months with more than 20 passages successfully cryopreserved and thawed. HIGHLIGHTS Two new fibroblast-like cell from testis and epithelium-like cell from ovary, derived from slender walking catfish Clarias nieuhofii (Valenciennes, 1840) have been successfully established by explant outgrowth technique Indicated the optimal cell density, fetal bovine serum and types of culture media for growing of both cells Chromosome analysis revealed that the typical diploid chromosome number is 66 (2n) in Clarias nieuhofii (Valenciennes, 1840) GRAPHICAL ABSTRACT

Karyotypic diversity among eight Zea mays L. varieties

Staining property of interphase nuclei and prophase chromosomes, diploid chromosome number, total chromosome length (TCL), symmetric and asymmetric indices of karyotype were studied in eight maize varieties released by BARI. 2n = 20 chromosomes were found in Barnali, Mohor, Khoi Vhutta, BS-1, B-5 and BM-7 whereas 2n = 22 chromosomes in China and 2n = 24 chromosomes in B-73 were observed. TCL was highest in Mohor (190.49 ± 5.61 μm) and lowest in B-73 (69.30 ± 2.51 μm). These varieties showed significant variation in cytogenetical parameters. Results obtained are expected to supplement genetic identification of maize varieties in variety conservation efforts.

First Record on Sex Chromosomes in a Species of the Family Cynodontidae: Cynodon gibbus (Agassiz, 1829)

The fish family Cynodontidae belongs to the superfamily Curimatoidea, together with the Hemiodontidae, Serrasalmidae, Parodontidae, Prochilodontidae, Chilodontidae, Curimatidae, and Anostomidae. The majority of the species of this superfamily that have been analyzed to date have a diploid chromosome number of 2n = 54. Differentiated sex chromosomes (with female heterogamety) have been observed only in the Prochilodontidae, Parodontidae, and Anostomidae. The present study provides the first description of differentiated sex chromosomes in the cynodontid species Cynodon gibbus, which has a ZZ/ZW system, and shows that repetitive DNA has played a fundamental role in the differentiation of these sex chromosomes.

On the hypothesis of dioicous – monoicous species pairs in the Mniaceae (Bryophyta); morphology, sexual condition and distiribution

Some early observations seemed to show that, in the Mniaceae, the doubling of the chromo-some set affects a change from dioicous to monoicous condition, larger size of the gametophyte including larger leaf cell size, and to a wider range of the monoicous counterpart. The Mniaceae taxa are divided into four groups based on their sexual condition and morphology. 1. Dioicous – monoicous counterparts which can be distinguished by morphological characters, 2. Dioicous – monoicous taxa which have no morphological, deviating characters, 3. Monoicous species mostly with diploid chromosome number for which no dioicous counterpart is known, and 4. The taxa in Mniaceae with only dioicous plants. Most of the monoicous species of the Mniaceae have wide ranges, but a few of them are endemics in geographically isolated areas. The dioicous species have either a wide holarctic range or a limited range in the forested areas of temperate and meridional North America, Europe and SE Asia, or in subtropical Asia. Some of the monoicous species are evidently autodiploids and a few of them are allopolyploids from cross-sections of two species. Quite recently, several new possible dioicous – monoicous relationships have been discovered.

Allium albanicum (Amaryllidaceae), a new species from Balkans and its relationships with A. meteoricum Heldr. & Hausskn. ex Halácsy

A new species, Alliumalbanicum, is described and illustrated from Albania (Balkan Peninsula). It grows on serpentines or limestone in open rocky stands with a scattered distribution, mainly in mountain locations. Previously, the populations of this geophyte were attributed to A.meteoricum Heldr. & Hausskn. ex Halácsy, described from a few localities of North and Central Greece. These two species indeed show close relationships, chiefly regarding some features of the spathe valves, inflorescence and floral parts. They also share the same diploid chromosome number 2n =16 and similar karyotype, while seed testa micro-sculptures and leaf anatomy reveal remarkable differences. There are also several morphological features that allow them to be differentiated at specific level. The inclusion of both species into a newly described section Pseudoscorodon of the subgen. Allium is proposed. An analytic key to the species, included in the new section, is also provided.

Comparative Chromosome Painting in Two Brazilian Stork Species with Different Diploid Numbers

Despite the variation observed in the diploid chromosome number of storks (Ciconiiformes, Ciconiidae), from 2n = 52 to 2n = 78, most reports have relied solely on analyses by conventional staining. As most species have similar macrochromosomes, some authors propose that karyotype evolution involves mainly fusions between microchromosomes, which are highly variable in species with different diploid numbers. In order to verify this hypothesis, in this study, the karyotypes of 2 species of storks from South America with different diploid numbers, the jabiru (Jabiru mycteria, 2n = 56) and the maguary stork (Ciconia maguary, 2n = 72), were analyzed by chromosome painting using whole chromosome probes from the macrochromosomes of Gallus gallus (GGA) and Leucopternis albicollis (LAL). The results revealed that J. mycteria and C. maguary share synteny within chromosome pairs 1-9 and Z. The syntenies to the macrochromosomes of G. gallus are conserved, except for GGA4, which is homologous to 2 different pairs, as in most species of birds. A fusion of GGA8 and GGA9 was observed in both species. Additionally, chromosomes corresponding to GGA4p and GGA6 are fused to other segments that did not hybridize to any of the macrochromosome probes used, suggesting that these segments correspond to microchromosomes. Hence, our data corroborate the proposed hypothesis that karyotype evolution is based on fusions involving microchromosomes. In view of the morphological constancy of the macrochromosome pairs in most Ciconiidae, we propose a putative ancestral karyotype for the family, including the GGA8/GGA9 fusion, and a diploid number of 2n = 78. The use of probes for microchromosome pairs should be the next step in identifying other synapomorphies that may help to clarify the phylogeny of this family.