KARYOTYPE AND BANDING-PATTERNS OF FEA TREE RAT (CHIROMYSCUS-CHIROPUS)

Fea's tree rat (Chiromyscus chiropus) is a very rare species which there are only a few specimens in the world. The chromosomes of two male specimens, collected from Xishuanbanna, Yunnan, are analysed by several banding technique (G-, C-bands, as well as Ag-staining). The diploid chromosome number is 22, and autosomes comprise 5 pairs of metacentrics, 2 pairs of subacrocentrics, and 3 pairs of acrocentrics. The X chromosome is a acrocentric, and Y is a micro-chromosome, almost a point, which could be a marker chromosome of the species and the genus. The centromeric C-bands are very faint, and C-bands of Nos. 1, 2, 9 and Y chromosome are negative. Only one pair Ag-NORs was found on No. 10 in the silver-stained karyotype. The relationship between morphologic and chromosomal features was discussed, and C-banded karyotype evolutionary trend has also been discussed. Moreover, the conventional karyotype of Niviventer confucianus was described.

Pericentric inversion events in karyotypic distinction of Brazilian lizards of genus Phyllopezus (Squamata, Gekkonidae) detected by chromosomal banding patterns

Cytogenetic investigations based on conventional and differential staining analysis (C-and replication R-banding and Ag-staining) were carried out on eight specimens of Phyllopezus periosus, 17 of P. pollicaris pollicaris, and one of P. pollicaris przewalskii collected from different localities of Brazil. P. periosus and P. p. pollicaris share the same diploid number of 2n = 40 chromosomes, and their karyotypes are very distinctive regarding to the number of biarmed and uniarmed chromosomes. After careful side-by-side comparison of R-banded chromosomes in both taxa, pronounced homology between, at least, eight pairs was revealed. The R-banding patterns allowed us to postulate that karyotype differentiation could be due to pericentric inversion events. P. p. przewalskii (2n = 38) exhibited a very similar karyotype to that found in P. p. pollicaris, except for the presence of one metacentric pair, which probably resulted from a Robertsonian rearrangement. Single and multiple pairs of NOR-bearing chromosomes, showing variation in number and location, were detected among the three forms of Phyllopezus. Similar C-banding patterns were found in P. periosus and P. p. pollicaris. Sex chromosomes were not positively identified.

Use of lymphocyte cultures for BrdU replication banding patterns in anuran species (Amphibia)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

DIFFERENTIATION OF DROSOPHILA-SERIDO (ISOFEMALE LINE A95F3) AND D-KOEPFERAE (ISOFEMALE LINE B20D2) - REPRODUCTIVE ISOLATION, DEVELOPMENT TIME AND POLYTENE CHROMOSOME-BANDING PATTERNS

Drosophila serido is considered to be a superspecies consisting of two species: D. serido, from Brazil and D. koepferae from Argentina and Bolivia. However this probably does not express the entire evolutionary complexity of its populations. Isofemale lines A95F3 (from Brazil) and B20D2 (from Argentina), at present representing, respectively, the first and second species, were analyzed for fertility and fecundity in pair-mating intracrosses and intercrosses, as well as for development time, banding patterns and asynapsis of polytene chromosomes in the isofemale lines and their hybrids.Although variations in experimental conditions resulted in some variability in the results, in general A95F3 fertility and fecundity were lower than in B20D2. Intercrosses of A95F3 females and B20D2 males showed lower fertility and fecundity than the reciprocal crosses, following more closely characteristics of the mother strains. This is in contrast to the results obtained by Fontdevilla et al. (An. Entomol. Soc. Amer. 81: 380-385, 1988) and may be due to the different geographic origin of D. serido strains they used in crosses to B20D2. This difference and others cited in the literature relative to aedeagus morphology, karyotype characteristics, inversion polymorphisms and reproductive isolation strongly indicate that A95F3 and D. serido from the State of Bahia, Brazil are not a single evolutionary entity, reinforcing the idea of greater complexity of the superspecies D. serido than is known today.The reproductive isolation mechanisms found operating between A95F3 and B20D2 were prezygotic and postzygotic, the latter included mortality at the larvae stage in both directions of crosses and sterility of male hybrids in intercrosses involving B20D2 females and A95F3 males. The two isofemale lines differed in egg-adult development time, which was also differently affected by culture medium composition.A95F3 and B20D2 also showed differences in the banding patterns of proximal regions of polytene chromosomes 2, 3 and X, a fixed inversion in chromosome 3 (here named 3t), apparently not described previously, and a high degree of asynapsis in hybrids.These observations, especially those related to reproductive isolation and chromosomal differentiation (including the karyotype, previously described, and the differentiation of banding patterns, described in this paper), as well as the extensive asynapsis observed in hybrids reinforces the distinct species status of A95F3 and B20D2 isofemale lines.

Comparative cytogenetic studies of eleven species of the Tropidurus torquatus group (Sauria, Tropiduridae), with banding patterns

The chromosomes of 173 specimens representing eleven species of the Tropidurus torquatus group, from 33 localities in Brazil, were analysed after Giemsa staining, C-banding, NORs, and replication banding techniques. A karyotype with 2n = 36, including 12 macrochromosomes and 24 microchromosomes (12 M + 24 m), and sex determination of the XY:XX type were found in Tropidurus cocorobensis, T. erythrocephalus, T. etheridgei, T. hispidus, T. hygomi, T. montanus, T. mucujensis, T. oreadicus, and T. torquatus. The two other species, T. itambere and T. psammonastes, presented 2n = 36 (12 M + 23 m) karyotype only in females while males had 2n = 35 (12 M + 23 m), due to the sex determination of the X(1)X(2)Y:X(1)X(1)X(2)X(2) type. Other interspecific differences as well as some intraspecific variation regarding the NORs and C-banding patterns have been observed, mainly in the microchromosome set. on the contrary, the macrochromosomes were highly conservative. Although consistent karyotypic diversity occurred in the torquatus group, the cytogenetic data obtained up to now did not allow us to clarify the phylogenetic relationships of the species. Nevertheless, the geographical distribution of the distinct cytotypes in T. hispidus and T. torquatus suggested that more than one species might be involved in each case.

Chromosome banding patterns of four species of bats, with special reference to a case of X-autosome translocation

The karyotypes of 4 species of bats, Artibeus lituratus (Phyllostomatidae), Pipistrellus pipistrellus (Vespertilionidae), Pteropus alecto and P. giganteus (Pteropodidae), were studied after several banding techniques. For A. lituratus, in which an X-autosome translocation was observed, an analysis of the replication pattern in the rearranged chromosome was also made after BrdU incorporation.

High Diversity in CMA(3)/DAPI-Banding Patterns in Heteropterans

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

PCR primed with minisatellite core sequences yields species-specific patterns and assessment of population variability in fishes of the genus Brycon

Minisatellite core sequences were used as single primers in polymerase chain reaction (PCR) to amplify genomic DNA in a way similar to the random amplified polymorphic DNA methodology. This technique, known as Directed Amplification of Minisatellite-region DNA, was applied in order to differentiate three neotropical fish species (Brycon orbignyanus, B. microlepis and B. lundii ) and to detect possible genetic variations among samples of the threatened species, B. lundii , collected in two regions with distinct environmental conditions in the area of influence of a hydroelectric dam. Most primers generated species-specific banding patterns and high levels of intraspecific polymorphism. The genetic variation observed between the two sampling regions of B. lundii was also high enough to suggest the presence of distinct stocks of this species along the same river basin. The results demonstrated that minisatellite core sequences are potentially useful as single primers in PCR to assist in species and population identification. The observed genetic stock differentiation in B. lundii associated with ecological and demographic data constitute a crucial task to develop efficient conservation strategies in order to preserve the genetic diversity of this endangered fish species.

R- and G-band patterns in Astyanax scabripinnis paranae (Pisces, Characiformes, Characidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Chromosome banding in three species of Brazilian toads (Amphibia-Bufonidae)

The chromosomes of Bufo crucifer, B. ictericus, and B. pamacnemis were studied by conventional staining as well as with C banding and NOR techniques. These species have a diploid number of 2n = 22 and identical karyotypes, composed of metacentric and submetacentric chromosomes. The C banding patterns and NOR data indicate that these species of Bufo are not differentiated by the distribution and amount of constitutive heterochromatin or the position of the nucleolar organizer regions.

Karyotypic patterns of seven species of molossid bats (Molossidae, Chiroptera)

G- and C- banding patterns of seven species of the bat family Molossidae, Eumops glaucinus, E. perotis; Molossops abrasus, M. remminckii, Molossus ater, M. molossus, and Nyctinomops laticaudatus, were identified. Comparisons among the karyotypes of these species showed extensive homologies between E. perotis, M. ater, M. molossus, M. abrasus, and N. laticaudatus, demonstrating inter- and intrageneric conservatism, and a lesser degree of homologies in M. temminckii and glaucinus, reflecting intrageneric variation, Chromosomal variation was due to inversions, Robertsonian rearrangements, translocations, and variations in the location of constitutive heterochromatin and nucleolus organizer regions. The chromosome corresponding to No. 5 in the M. ater karyotype is discussed. We suggest that the Nyctinomops and Molossops karyotypes represent the primitive condition and that Molossus and Eumops have derived karyotypes.

Restriction endonuclease banding and digestion resistant heterochromatin in triatomines, genus Panstrongylus

The present work realized a comparative study in meiosis of two triatomines, Panstrongylus herreri and P. megistus, by cytogenetic techniques involving the restriction endonucleases Hae III and Alu I and C-banding. The system of sex chromosomes in Panstrongylus is of the X1X2Y type, and experiments corroborated the common origin hypothesis of the X chromosomes by fragmentation of single X. In both species the restriction endonucleases (RE) presented banding patterns in part similar to C-banding. However, in some early meiotic phases it was possible to verify differentiation of the heterochromatic pattern. This work suggests that other elements besides presence of recognition sites, such as chromatin packing degree and DNA-protein interaction, act in RE results, since digestion patterns occur in early spermatogenesis. However, metaphase chromosomes were practically inaccessible to the endonucleases.

A COMPARATIVE-STUDY OF KARYOTYPES OF MUNTJACS BY CHROMOSOME PAINTING

We have used a combination of chromosome sorting, degenerate oligonucleotide-primed polymerase chain reaction (DOP-PCR), chromosome painting and digital image capturing and processing techniques for comparative chromosome analysis of members of the genus Muntiacus. Chromosome-specific ''paints'' from a female Indian muntjac were hybridised to the metaphase chromosomes of the Gongshan, Black, and Chinese muntjac by both single and three colour chromosome painting. Karyotypes and idiograms for the Indian, Gongshan, Black and Chinese muntjac were constructed, based on enhanced 4', 6-diamidino-2-phenylindole (DAPI) banding patterns. The hybridisation signal for each paint was assigned to specific bands or chromosomes for all of the above muntjac species. The interspecific chromosomal homology was demonstrated by the use of both enhanced DAPI banding and comparative chromosome painting. These results provide direct molecular cytogenetic evidence for the tandem fusion theory of the chromosome evolution of muntjac species.

Mapping chromosomal homologies between humans and two langurs (Semnopithecus francoisi and S-Phayrei) by chromosome painting

Chromosomal homologies were established between human and two Chinese langurs (Semnopithecus francoisi, 2n=44, and S. phayrei, 2n=44) by chromosome painting with chromosome-specific DNA probes of all human chromosomes except the Y. Both langur species showed identical hybridization patterns in addition to similar G-banding patterns. In total, 23 human chromosome-specific probes detected 30 homologous chromosome segments in a haploid langur genome. Except for human chromosomes 1, 2, 6, 16 and 19 probes, which each gave signals on two non-homologous langur chromosomes respectively, all other probes each hybridized to a single chromosome. The results indicate a high degree of conservation of chromosomal synteny between human and these two Chinese langurs. The human chromosome 2 probe painted the entire euchromatic regions of langur chromosomes 14 and 19. Human chromosome 1 probe hybridized to three regions on langur autosomes, one region on langur chromosome 4 and two regions on langur chromosome 5. Human 19 probe hybridized on the same pattern to one region on chromosome 4 and to two regions on langur chromosome 5, where it alternated with the human chromosome 1 probe. Human 6 and 16 probes both hybridized to one region on each of the two langur autosomes 15 and 18. Only two langur chromosomes (12 and 21) were each labelled by probes specific for two whole human chromosomes (14 and 15 and 21 and 22 respectively). Comparison of the hybridization patterns of human painting probes on these two langurs with the data on other Old World primates suggests that reciprocal and Robertsonian translocations as will as inversions could have occurred since the divergance of human and the langurs from a common ancestor. This comparison also indicates that Asian colobines are karyotypically more closely related to each other that to African colobines.