Genomic portraits: karyotyping of some Nigerian bat species

In this study, chromosome numbers and karyotypes of 11 bat species were analyzed. The animals were captured alive by using nets and handpicking and then chromosome preparations were made from bone marrow cells with colchicines method. Bats were collected from nine localities in Ethiopia, namely: Arbaminch, Batu/Ziway, Waliso, Fiche, Bishoftu/Debre-Zeit, Sof-Umar, Koka, Merehabete and Adaba. The species name and the chromosome number (2n) with their corresponding autosomal fundamental number (FN) obtained are: Hipposideros caffer (2n = 32, FN = 60/62) and Triaenops persicus (2n = 36, FN = 60) are belong to family Hipposideridae; Chaerephon pumilus (2n = 48 and FN = 54/56) with metacentric, acrocentric and acrocentric chromosomes, Chaerephon leucogaster (2n = 48, FN = 54), and Mops condylura (2n = 48, FN = 54) are members of the family Molossidae; Pipistrellus pipistrellus (2n = 36, FN = 52) with metacentric and acrocentric chromosomes, Neoromicia nanus (2n = 36, FN = 48), Miniopterus africanus (2n = 46, FN = 54) and Scotophilus dingani (S. viridis) 2n = 36, FN = 54) with metacentric and acrocentric chromosomes are members of the family Vespertilionidae; Micropteropus pusillus (2n = 35/36, FN = 68) with all the chromosomes being biarmed belongs to family Pteropidae; Nycteris thebaica (2n = 42, FN = 78/80) with 40 biarmed and two acrocentric chromosomes is member of family Nycteridae. Totally, 15 different types of chromosome number, fundamental number and morphology were identified. C. leucogaster has not been recorded in the Ethiopian bats list before. All of these species are karyologically described for the first time from Ethiopia. Some of the karyotypic findings in the present study are in agreement with previous reports from other countries, except for the lack of report on one species (C. leucogaster). In our study, the encountered problems include: lack of karyotypic literatures on Ethiopian bats and taxonomic identification. It is recommended that more karyotypic study of bat species in the country should be done using additional techniques and due attentions should be given to the conservations of this threatened groups of animals because they are declining in diversity as well as in density.

We provide new data on the karyologic patterns of the Andean rodents Aepeomys and Thomasomys, including the 1st karyotypic description of A. lugens and T. vestitus. Two differentiated chromosomal formulae were found for Aepeomys in Venezuela; they are a diploid chromosome number (2n) 5 28, fundamental number (FN) 5 48 karyotype corresponding to A. lugens and a2 n5 44; FN 5 46 karyotype for an unnamed population (Aepeomys sp.). According to the structure of these 2 karyotypes and the distribution of constitutive heterochromatin (scarce and restricted to a few chromosomes in A. lugens versus abundant and scattered among chromosomes in Aepeomys sp.), we suggest that Aepeomys sp. is a more primitive form than A. lugens. T. laniger and T. vestitus showed karyotypes of 2n 5 42, FN 5 40 and 2n 5 44, FN 5 42, respectively; the latter has an additional pair of small-sized metacentric chromosomes and an acrocentric X chromosome (metacentric in T. laniger). Our results suggest that Aepeomys and Thomasomysare closely related taxa in terms of their karyologic patterns.

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.

Karyotypic studies were carried out on the Black Rat, Rattus rattus, with the aim of determining its chromosome number. The chromosomes were prepared from the bone marrow of a male rat treated with 0.04% colchicine. Chromosomes in well spread cells were counted and measured using Motic Images Plus - a computer software. Arm ratios and centromeric indices were determined from these measurements. The chromosomes were classified based on the centromeric indices obtained. Ideograms were also constructed from the measurements. Photomicrographs of well spread mitotic metaphase chromosomes were used to construct a standard karyotype for the species. A diploid chromosome number of 2n = 38 with a fundamental number (FN) of 76 was obtained for the local population of the Black Rat, Rattus rattus, here in the University of Nigeria, Nsukka. The karyotype shows a somewhat sharp break in chromosome lengths between chromosomes 4 and 5, and thereafter, a gradual decrease in size. From the constructed idiogram, there is a gradual decrease in length from one chromosome pair to another. The X and Y complements sharply deviated from this trend.

Achiridae is an important family of the order Pleuronectiformes widely distributed in North, Central, and South America with freshwater and marine species. In the present study cytogenetic analyses comprising conventional and molecular techniques were carried out in seven species of this family. The following diploid numbers (2n) and fundamental numbers (FN) were obtained: Achirus declivis 2n=34, FN=52; Achirus lineatus 2n=40, FN=66; Catathyridium jenynsi 2n=40 and FN=50; Gymnachirus nudus 2n=36 and FN=50; Hypoclinemus mentalis 2n=38 and FN=54; Trinectes paulistanus 2n=42 and FN=52; and Trinectes sp. 2n=38 and FN=54. All species presented a single nucleolar organizer region (NOR) bearing chromosome pair and C-band positive segments mainly distributed at the pericentromeric position. The wide variation observed in chromosome number and FN suggests the occurrence of larger chromosome rearrangements in the family Achiridae if compared with other families of the same order.

In the present investigation, karyotype and microsatellites pattern in the chromosome of Gyldenstolpe’s Frog (Limnonectes gyldenstolpei) have been analyzed. The aspect of chromosome numbers, morphology, nucleolus organizer region (NOR) locations and microsatellites pattern [d(CA)15, d(CGG)10, d(GC)15, d(TA)15]. We provided the karyotype and idiogram of this species by conventional staining, Ag-NOR banding and Fluorescence in situ hybridization techniques. For the study, five male and female samples collected from northern Thailand, were used. The metaphase chromosome preparations were prepared from the bone marrows by the standard protocol. The result shows that L. gyldenstolpei had the diploid chromosome number (2n) was 26 and the fundamental number (NF) were 56 in both males and females. The karyotype is composed of 4 large metacentric, 4 large submetacentric, 2 medium metacentric, 14 small metacentric and 2 small submetacentric chromosomes. The NORs bearing chromosome were in close to the telomere region on chromosome pair 1. In addition, the microsatellite d(CGG)10 and (GC)15 hybridization results confirmed the NOR region. The in situ localization pattern of d(CA)15 microsatellites was positive on all telomere chromosome, while microsatellites d(TA)15 have no signal on chromosome. Here we provide a classical and some molecular genetics information for L. gyldenstolpei useful as a species specific marker.

Abstract. Chaiyasan P, Mingkwan B, Jantarat S, Suwannapoom C, Cioffi MDB, Liehr T, Talumphai S, Tanomtong A, Supiwong W. 2021. Classical and molecular cytogenetics of Belontia hasselti (Perciformes: Osphronemidae): Insights into the ZZ/ZW sex chromosome system. Biodiversitas 22: 546-554. Karyotype of Java combtail fish, Belontia hasselti, from To Daeng peat swamp forest, Narathiwat Province, southern Thailand, was studied for the first time. Mitotic chromosome preparations were prepared directly from kidney cells from ten male and ten female fish. Conventional staining, NOR banding, and molecular cytogenetics with fluorescence in situ hybridization (FISH) using 5S and 18S rDNAs, as well as microsatellites d(CA)15 and d(CAC)10 as probes were applied. The diploid chromosome number (2n) was 48 and a female heterogametic sex chromosome system (ZZ/ZW) is suggested. The fundamental numbers (NF) were 48 and 49 in males and females, respectively. The karyotype of males comprised 48 telocentric chromosomes while the female ones were composed of one metacentric and 47 telocentric chromosomes. A single Ag-NOR-bearing chromosomal pair was identified. The NOR positions were characterized at the interstitial sub-centromeric region of pair 13, which coincided with signals of 18S rDNA and d(CAC)10 probes. The 5S rDNA signals were located at interstitial sites of the largest telocentric pair. Microsatellite d(CA)15 repeats were highly distributed throughout almost all entire chromosomes except for centromeric regions on some chromosome pairs, including sex chromosomes. The present study is a novel report for a ZZ/ZW sex chromosome system of this fish family in Thailand.

The karyotypes of three shrew species (Mammalia, Soricomorpha, Soricidae) from Nepal were examined for the first time. Based on the karyotypes and overall differences in skull size, the current Episoriculus caudatus appeared to include two distinct species: the larger E. caudatus and the smaller Episoriculus sacratus. Episoriculus sacratus has three subspecies, E. s. soluensis in Nepal and Sikkim, E. s. umbrinus in Assam, Myanmar and the Yunnan Province of China, and E. s. sacratus in the Sichuan Province of China. Soriculus nigrescens had a diploid chromosome number (2n) and fundamental number (FN), including two X chromosomes, of 64 and 92, respectively, consisting of 11 metacentric or submetacentric, two subtelocentric and 18 acrocentric pairs of autosomes, a metacentric X and an acrocentric Y chromosome. Episoriculus sacratus soluensis had 2n = 74 and FN = 126, consisting of 12 metacentric or submetacentric, 13 subtelocentric and 11 acrocentric pairs of autosomes, a submetacentric X and an acrocentric Y chromosome. Episoriculus caudatus had 2n = 60 and FN = 118, consisting of 19 metacentric or submetacentric, nine subtelocentric and one acrocentric pair of autosomes, a subtelocentric X and an acrocentric Y chromosome. The karyotypes of these three species are characterized by their large 2n and FN values compared with other Soricidae.

Successful crossbreeding between Oreochromis niloticus and Sarotherodon melanotheron to produce a commercial hybrid has been difficult. The karyotypes and isoenzyme of these two species and their reciprocal hybrids (O. niloticus female × S. melanotheron male, S. melanotheron female × O. niloticus male, the last not included in the isoenzyme study) were investigated via metaphase chromosomes obtained from head kidney cells and electropherogram of lactate dehydrogenase (LDH) isoenzymes from the liver, kidney, white muscle, heart, and eye balls. The diploid chromosome number (2n=44) and the fundamental number (NF=50) of the four tilapia genotypes were the same. However, the karyotype of O. niloticus had three pairs of sub-metacentric (sm), twelve pairs of sub-telocentric (st), and seven pairs of telocentric (t) chromosomes, while S. melanotheron had one pair of metacentric (m), two pairs of sm, 12 pairs of st, and seven pairs of t chromosomes. The reciprocal hybrids both showed a mixed karyotype range between their parents: 0.5 pair of m, 2.5 pairs of sm, 12 pairs of st, and seven pairs of t chromosomes. In view of the electropherogram of isozymes, only the LDH of the kidney showed significant clear bands, with five bands in O. niloticus, three bands in S. melanotheron, and duplicated six bands in the hybrids. The bands varied depending on their activities and mobilities. We considered that the differences in karyotype and isoenzyme were related to the genetic mechanism for post-mating isolation, and provided some additional basic genetic background of their taxonomy.

In this study, Enteromius parablabes [1] was analyzed with the aim of providing baseline information regarding the diploid chromosome number and karyotype differences of both sexes. The diploid chromosome number (2n) was 50 for both sexes, and this corresponds to the diploid chromosome number reported for most small African Barbus species. The fundamental number (NFa) of the male and female was 81 and 98 respectively. The first pair of metaphase chromosomes which has been suggested to be a marker for the small African Barbus group was conspicuously larger in the female karyotype. The karyotype of the female consisted more of metacentric (39m + 7sm + 2st + 2t) which is common in the group while the karyotype of the male which consisted more of telocentric chromosomes (10m + 21st + 19T) is scarce. The chromosomal number obtained for E. parablabes demonstrates its diploid status in the context of the ploidy lines characteristic of the African Barbus assemblage.

Cyprininae are a highly diversified but demonstrably monophyletic lineage of cypriniform fishes. Here, the karyotype and chromosomal characteristics of Hypsibarbusmalcolmi (Smith, 1945) and H.wetmorei (Smith, 1931) were examined using conventional, nucleolus organizing regions (NORs) and molecular cytogenetic protocols. The diploid chromosome number (2n) of H.malcolmi was 50, the fundamental number (FN) was equal to 62, and the karyotype displayed 8m + 4sm + 38a with NORs located at the centromeric and telomeric positions of the short arms of chromosome pairs 1 and 2, respectively. 2n of H.wetmorei was 50, FN 78, karyotype 14m + 14sm + 22a with the NORs at the telomeric position of the short arm of chromosome pair 2. 2n and FN in males and females were identical. Fluorescence in situ hybridization using different microsatellite motifs as probes also showed substantial genomic divergence between both studied species. In H.wetmorei, (CAG)n and (CAC)n microsatellites accumulated in the telomeric regions of all chromosomes, while in H.malcolmi, they had scattered signals on all chromosomes. Besides, the (GAA)n microsatellites were distributed along all chromosomes of H.malcolmi, but there was a strong hybridization pattern in the centromeric region of a single pair in H.wetmorei. These cytogenomic difference across the genomes of these Hypsibarbus Rainboth, 1996 species are markers for specific evolutionary differentiation within these two species.

The distribution of nucleolar organizer regions (NORs) in Cricetulus migratorius and Meriones tristrami from Central Anatolia was determined. In the karyotype of Cricetulus migratorius the diploid number, fundamental number, and fundamental autosomal number are 22, 44, and 40, respectively. The diploid number, fundamental number, and fundamental autosomal number of Meriones tristrami are 72, 84, and 80, respectively. In Cricetulus migratorius, NORs occur in the telomeric regions of metacentric and subtelocentric autosome pairs. Furthermore, terminally located NORs in metacentric and acrocentric autosomes of Meriones tristrami are presented in this present paper.

The Chinese long-tailed mole (Scaptonyx fusicaudus) closely resembles American (Neurotrichus gibbsii) and Japanese (Dymecodon pilirostris and Urotrichus talpoides) shrew moles in size, appearance, and ecological habits, yet it has traditionally been classified either together with (viz subfamily Urotrichinae) or separately (tribe Scaptonychini) from the latter genera (tribe Urotrichini sensu lato). We explored the merit of these competing hypotheses by comparing the differentially stained karyotypes of S. fusicaudus and N. gibbsii with those previously reported for both Japanese taxa. With few exceptions, diploid chromosome number (2n = 34), fundamental autosomal number (FNa = 64), relative size, and G-banding pattern of S. fusicaudus were indistinguishable from those of D. pilirostris and U. talpoides. In fact, only chromosome 15 differed significantly between these species, being acrocentric in D. pilirostris, subtelocentric in U. talpoides, and metacentric in S. fusicaudus. This striking similarity is difficult to envisage except in light of a shared common ancestry, and is indicative of an exceptionally low rate of chromosomal evolution among these genera. Conversely, the karyotype of N. gibbsii deviates markedly in diploid chromosome and fundamental autosomal number (2n = 38 and FNa = 72, respectively), morphology, and G-banding pattern from those of Scaptonyx and the Japanese shrew moles. These differences cannot be explained by simple chromosomal rearrangements, and suggest that rapid chromosomal reorganization occurred in the karyotype evolution of this species, possibly due to founder or bottleneck events.

Gardner, A. L. (National Fish and Wildlife Laboratory, Fish and Wildlife Service, National Museum of Natural History, Washington, D.C. 20560) 1977. Chromosomal variation in Vampyressa and a review of chromosomal evolution in the Phyllostomidae (Chiroptera). Syst. Zool., 26:300-318.-Comparisons of the karyotypes of the species of Vampyressa suggest two modes of chromosomal rearrangements in the derivation of the Vampyressa karyotypes: pericentric inversions in V. brocki, V. nymphaea, and V. bidens; and translocations (fusions) in V. melissa and the variants of V. pusilla. This Vampyressa phylogenetic model was used to evaluate the possible derivations of the chromosomal patterns of the 97 species of phyllostomid bats whose karyotypes are known. Sufficient variation to indicate probable evolutionary patterns, in addition to that outlined for Vampyressa, was found at the species level for Micronycteris and Tonatia, and at the generic level for the Glossophaginae, Carolliinae, and Stenoderminae. The analysis supports the points of view presented herein that (1) the common (often considered the ancestral) 2n = 32, FN = 60 configuration was independently acquired by three or more evohitionary lineages and, therefore, must be considered to be derived; (2) the primitive phyllostomid karyotype had a high diploid number (near 40, but possibly as high as 46) and a low fundamental number (near minimum); (3) there was a general trend toward reduction in diploid numbers concomitant with maximization of fundamental numbers; and (4) totally biarmed autosomal configurations, which characterize the majority of the Phyllostomidae, are comparatively more stable than those karyotypes in which half or more of the autosomes are uniarmed. Fourteen karyotypes are reported here for the first time, including that of Vampyressa melissa, which has the lowest diploid number known in the Chiroptera (2n = 14). [Phyllostomidae; evolution; karyotypes.] As presently understood, Vampyressa contains five species (Peterson, 1968). Karyotypically, these five demonstrate sufficient variation to permit not only an evaluation of chromosomal evolution within the genus but insight into the karotypic origins and the directions and kinds of chromosomal change that may have occurred within the family Phyllostomidae. This analysis is based on chromosomal material processed in the field as well as on published karyotype descriptions. Field prepared material was processed by the colchicine-hypotonic citrate technique outlined by Patton (1967). Chromosomal morphology and fundamental number (FN) are as defined by Patton (1967). The specimens whose chromosomes are described herein for the first time are deposited in the collections of the Louisiana State University Museum of Zoology (LSUMZ), the Museum of Vertebrate Zoology, University of California, Berkeley (MVZ), and the National Museum of Natural History (USNM) as indicated in Table 1. KARYOTYPES OF Vampyressa Of the Vampyressa karyotypes discussed here, the V. melissa and V. bidens karyotypes and the V. pusilla variant from Peru have not been described previously. Vampyressa pusilla.-Two geographically distinctive chromosomal variants are known (Baker et al., 1973) and a third from Peru is described as follows: 2n =22 (&), 23 (9); FN=22 (Fig. 1, B and C). Autosomes: 1 unpaired large metacentric and 9 pairs of medium-sized to small acrocentrics. The female has an additional pair of autosomes, the smallest in the complement, here considered to be acrocentric for the determination of FN although each bears a very short second arm. The male possesses an unpaired acrocentric (designated XA in Fig. 1C), which for descrip-

There are two species of Neotropical Round-eared bats, Tonatia bidens Spix, 1823 and Tonatia saurophila Koopman & Williams, 1951, which present highly similar morphological characteristics that can lead to errors of identification. Specimens originally identified as T. bidens have recently been reclassified as T. saurophila, and the only karyotype documented previously for these species was 2n = 16, FN = 20. In the present study, specimens of Tonatia collected in the municipality of Barra do Garcas, in the Brazilian state of Mato Grosso, were analyzed morphologically, using conventional cytogenetic techniques (C-banding, Ag-NOR, and CMA3), and through sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene. In the specimens morphologically identified as T. bidens, the diploid number (2n) was 26, and the fundamental number (FN), 38, while in T. saurophila, 2n = 16 and FN = 20, which is the karyotype also described previously for T. bidens. The dendograms obtained with sequences of the COI marker resulted in the formation of two distinct groups between T. bidens and T. saurophila, consistent with the two species, with a high sequence divergence value (14.22%). Distinct clades were also observed between T. bidens and the other phyllostomines analyzed in this study, with T. bidens also close to Phyllostomus hastatus (14.18% of sequence divergence).