Chromosome differentiation patterns during cichlid fish evolution

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

Comparative chromosome mapping of repetitive sequences. Implications for genomic evolution in the fish, Hoplias malabaricus

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

Supernumerary chromosome inheritance in the curimbata (Prochilodus lineatus) of the Mogi-Guacu River

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

Chromosome spreading of associated transposable elements and ribosomal DNA in the fish Erythrinus erythrinus. Implications for genome change and karyoevolution in fish

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

B chromosome in the beetle Coprophanaeus cyanescens (Scarabaeidae): emphasis in the organization of repetitive DNA sequences

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

Cytogenetic mapping of the W chromosome in the genus Leporinus (Teleostei, Anostomidae) using a highly repetitive DNA sequence

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

Extreme degree of chromosome number variability in species of the spider genus Scytodes (Araneae, Haplogynae, Scytodidae)

Genus Scytodes includes most species of the spider family Scytodidae. Until now, 187 species of the genus have been described. In spite of this great diversity, only three Scytodes species were karyotyped so far. The present paper provides for the first time karyotype analysis of two synanthropic species, Scytodes fusca and Scytodes itapevi. Furthermore, new data on karyotype of Scytodes globula are also provided using conventional and differential cytogenetical procedures. The diploid number in the genus Scytodes varied considerably, namely from 2n = 13 to 2n = 31. The diploid number found in S. globula (2n male = 13) is the lowest in haplogyne spiders with monocentric chromosomes. Except S. globula, this number has been found only in one haplogyne spider with monocentric chromosomes, namely Ochyrocera sp. (Ochyroceratidae). on the contrary, the diploid number of S. fusca (2n male = 31) is one of the highest diploid numbers recorded in haplogyne spiders. The degree of intrageneric variation found in the genus Scytodes is the highest recorded in araneomorph spiders with monocentric chromosomes so far. Some karyotype characteristics (diploid number, chromosome morphology, total chromosome length, and distribution of constitutive heterochromatin) allowed us to postulate a close relationship between S. globula and S. itapevi. According to the karyotype data, S. fusca is not closely related to these two species. This conclusion corroborates a recent taxonomic work that grouped S. globula, S. itapevi, and other four Scytodes species in the 'globula group'.

Genomic organization and comparative chromosome mapping of the U1 snRNA gene in cichlid fish, with an emphasis in Oreochromis niloticus

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

Chromosomal mapping of repetitive DNAs in the beetle Dichotomius geminatus provides the first evidence for an association of 5S rRNA and histone H3 genes in insects, and repetitive DNA similarity between the B chromosome and A complement

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

Chromosome evolution in three Brazilian Leptodactylus species (Anura, Leptodactylidae), with phylogenetic considerations

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

Chromosomal mapping of rDNAs and H3 histone sequences in the grasshopper rhammatocerus brasiliensis (acrididae, gomphocerinae): extensive chromosomal dispersion and co-localization of 5S rDNA/H3 histone clusters in the A complement and B chromosome

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Comparative karyotype analysis and chromosome evolution in the genus Aplastodiscus (Cophomantini, Hylinae, Hylidae)

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

Chromosome banding in three species of Hypsiboas (Hylidae, Hylinae), with special reference to a new case of B-chromosome in anuran frogs and to the reduction of the diploid number of 2n=24 to 2n=22 in the genus

The chromosomes of hylids Hypsiboas albopunctatus, H. raniceps, and H. crepitans from Brazil were analyzed with standard and differential staining techniques. The former species presented 2n = 22 and 2n = 23 karyotypes, the odd diploid number is due to the presence of an extra element interpreted as B chromosome. Although morphologically very similar to the small-sized chromosomes of the A complement, the B was promptly recognized, even under standard staining, on the basis of some characteristics that are usually attributed to this particular class of chromosomes. The two other species have 2n = 24, which is the chromosome number usually found in the species of Hypsiboas karyotyped so far. This means that 2n = 22 is a deviant diploid number, resulted from a structural rearrangement, altering the chromosome number of 2n = 24 to 2n = 22. Based on new chromosome data, some possibilities were evaluated for the origin of B chromosome in Hypsiboas albopunctatus, as well as the karyotypic evolution in the genus, leading to the reduction in the diploid number of 2n = 24 to 2n = 22.

A radiation hybrid map of river buffalo (Bubalus bubalis) chromosome 7 and comparative mapping to the cattle and human genomes

A preliminary radiation hybrid (RH) map containing 50 loci on chromosome 7 of the domestic river buffalo Bubalus bubalis (BBU; 2n = 50) was constructed based on a comparative mapping approach. The RH map of BBU7 includes thirty-seven gene markers and thirteen microsatellites. All loci have been previously assigned to Bos taurus (BTA) chromosome BTA6, which is known for its association with several economically important milk production traits in cattle. The map consists of two linkage groups spanning a total length of 627.9 cR(5,000). Comparative analysis of the BBU7 RH 5,000 map with BTA6 in cattle gave new evidence for strong similarity between the two chromosomes over their entire length and exposed minor differences in locus order. Comparison of the BBU7 RH 5,000 map with the Homo sapiens (HSA) genome revealed similarity with a large chromosome segment of HSA4. Comparative analysis of loci in both species revealed more variability than previously known in gene order and several chromosome rearrangements including centromere relocation. The data obtained in our study define the evolutionarily conserved segment on BBU7 and HSA4 to be between 3.5 megabases (Mb) and 115.8 Mb in the HSA4 (genome build 36) DNA sequence. Copyright (c) 2008 S. Karger AG, Basel.

Assignment of chromosome rearrangements between X chromosomes of human and cattle by laser microdissection and Zoo-FISH

Cross-species fluorescence in-situ hybridization (Zoo-FISH) was performed on cattle metaphase spreads using Homo sapiens X chromosome (HSAX) painting probes specific for the p- and q-arms to identify the cytogenetic location of a chromosome breakpoint between HSAX and the Bos taurus X chromosome (BTAX). The existence of a breakpoint is strongly suggested by recent radiation hybrid and FISH mapping results. Hybridization probes were generated by microdissection of HSAX p- and q-arms using the contact-free technology of Laser Microdissection and Pressure Catapulting (LMPC), amplification of the isolated chromosome material by DOP-PCR, and labelling of the PCR products with digoxigenin in a secondary PCR. Independent Zoo-FISH of the two painting probes on bovine metaphase chromosomes (detected by antidigoxigenin-fluorescein) resulted in clear hybridization signals on BTAX. A breakpoint was identified between HSAXp and HSAXq on BTAX, and narrowed down between the G-bands BTAXq25 and BTAXq26. The assumed centromere transposition between HSAX and BTAX associated with the rearranged chromosome segments is supported by cytogenetic assignments of the genes BGN and G6PD to BTAX.