Tracking the evolution of sex chromosome systems in Melanoplinae grasshoppers through chromosomal mapping of repetitive DNA sequences

Background: The accumulation of repetitive DNA during sex chromosome differentiation is a common feature of many eukaryotes and becomes more evident after recombination has been restricted or abolished. The accumulated repetitive sequences include multigene families, microsatellites, satellite DNAs and mobile elements, all of which are important for the structural remodeling of heterochromatin. In grasshoppers, derived sex chromosome systems, such as neo-XY♂/XX♀ and neo-X1X2Y♂/X 1X1X2X2♀, are frequently observed in the Melanoplinae subfamily. However, no studies concerning the evolution of sex chromosomes in Melanoplinae have addressed the role of the repetitive DNA sequences. To further investigate the evolution of sex chromosomes in grasshoppers, we used classical cytogenetic and FISH analyses to examine the repetitive DNA sequences in six phylogenetically related Melanoplinae species with X0♂/XX♀, neo-XY♂/XX♀ and neo-X1X2Y♂/X1X1X 2X2♀ sex chromosome systems. Results: Our data indicate a non-spreading of heterochromatic blocks and pool of repetitive DNAs (C 0 t-1 DNA) in the sex chromosomes; however, the spreading of multigene families among the neo-sex chromosomes of Eurotettix and Dichromatos was remarkable, particularly for 5S rDNA. In autosomes, FISH mapping of multigene families revealed distinct patterns of chromosomal organization at the intra- and intergenomic levels. Conclusions: These results suggest a common origin and subsequent differential accumulation of repetitive DNAs in the sex chromosomes of Dichromatos and an independent origin of the sex chromosomes of the neo-XY and neo-X1X2Y systems. Our data indicate a possible role for repetitive DNAs in the diversification of sex chromosome systems in grasshoppers. © 2013Palacios-Gimenez et al.; licensee BioMed Central Ltd.

Mapeamento RH comparativo do cromossomo X de búfalo de rio (Bubalus bubalis) / Patrícia Ianella

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Chromosome comparison between two species of Phyllostomus (Chiroptera - Phyllostomidae) from Eastern Amazonia, with some phylogenetic insights

Os cariótipos de Phyllostomus discolor e P. hastatus da Amazônia oriental são estudados por bandeamentos G, C, G/C sequencial e coloração Ag-NOR. Ambas as espécies apresentaram 2n = 32, sendo o complemento autossômico composto por 15 pares bi-armed em P. discolor e 14 bi-armed mais 1 par acrocêntrico em P. hastatus. O cromossomo X é um submetacêntrico médio e o Y é um pequeno acrocêntrico em ambas as espécies. O presente estudo encontrou apenas uma diferença entre os cariótipos de P. discolor e P. hastatus: o menor autossomo (par 15) é metacêntrico em discolor e acrocêntrico em hastatus. Este resultado é melhor explicado por uma inversão pericêntrica. O bandeamento C revelou heterocromatina constitutiva na região centromérica de todos os cromossomos, e os sítios NOR foram localizados na região distal do par 15, em ambas as espécies. O táxon P. discolor é considerado primitivo para o gênero Phyllostomus e supõe-se que a forma metacêntrica do par 15 seja a condição primitiva, que foi rearranjada por uma inversão pericêntrica, originando a forma acrocêntrica encontrada em P. hastatus.

Efeitos da clonagem na inativação do cromossomo X e da regulação nutricional do metabolismo da metionina na qualidade ovocitária em bovinos

Pós-graduação em Medicina Veterinária - FMVZ

Interploidy hybridization in sympatric zones: the formation of Epidendrum fulgens x E. puniceoluteum hybrids (Epidendroideae, Orchidaceae)

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

Chromosome Evolution in Dendropsophini (Amphibia, Anura, Hylinae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Comparative Chromosome Mapping of U2 snRNA and 5S rRNA Genes in Gymnotus Species (Gymnotiformes, Gymnotidae): Evolutionary Dynamics and Sex Chromosome Linkage in G. pantanal

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

Homomorphic Sex Chromosomes and the Intriguing Y Chromosome of Ctenomys Rodent Species (Rodentia, Ctenomyidae)

Unlike the X chromosome, the mammalian Y chromosome undergoes evolutionary decay resulting in small size. This sex chromosomal heteromorphism, observed in most species of the fossorial rodent Ctenomys, contrasts with the medium-sized, homomorphic acrocentric sex chromosomes of closely related C. maulinus and C. sp. To characterize the sequence composition of these chromosomes, fluorescent banding, self-genomic in situ hybridization, and fluorescent in situ hybridization with an X painting probe were performed on mitotic and meiotic plates. High molecular homology between the sex chromosomes was detected on mitotic material as well as on meiotic plates immunodetected with anti-SYCP3 and anti-gamma H2AX. The Y chromosome is euchromatic, poor in repetitive sequences and differs from the X by the loss of a block of pericentromeric chromatin. Inferred from the G-banding pattern, an inversion and the concomitant prevention of recombination in a large asynaptic region seems to be crucial for meiotic X chromosome inactivation. These peculiar findings together with the homomorphism of Ctenomys sex chromosomes are discussed in the light of the regular purge that counteracts Muller's ratchet and the probable mechanisms accounting for their origin and molecular homology. (C) 2014 S. Karger AG, Basel

A new species of Endecous Saussure, 1878 (Orthoptera, Gryllidae) from northeast Brazil with the first X(1)X(2)0 chromosomal sex system in Gryllidae

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Construction and preliminary characterization of a river buffalo bacterial artificial chromosome library

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

Chromosomal evolution in Pleurothallidinae (Orchidaceae: Epidendroideae) with an emphasis on the genus Acianthera: chromosome numbers and heterochromatin

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Chromosome evolution in lycosoid spiders (Araneomorphae): a scenario based on analysis of seven species of the families Lycosidae, Senoculidae and Trechaleidae

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

A step to the gigantic genome of the desert locust: chromosome sizes and repeated DNAs

The desert locust (Schistocerca gregaria) has been used as material for numerous cytogenetic studies. Its genome size is estimated to be 8.55 Gb of DNA comprised in 11 autosomes and the X chromosome. Its X0/XX sex chromosome determinism therefore results in females having 24 chromosomes whereas males have 23. Surprisingly, little is known about the DNA content of this locust's huge chromosomes. Here, we use the Feulgen Image Analysis Densitometry and C-banding techniques to respectively estimate the DNA quantity and heterochromatin content of each chromosome. We also identify three satellite DNAs using both restriction endonucleases and next-generation sequencing. We then use fluorescent in situ hybridization to determine the chromosomal location of these satellite DNAs as well as that of six tandem repeat DNA gene families. The combination of the results obtained in this work allows distinguishing between the different chromosomes not only by size, but also by the kind of repetitive DNAs that they contain. The recent publication of the draft genome of the migratory locust (Locusta migratoria), the largest animal genome hitherto sequenced, invites for sequencing even larger genomes. S. gregaria is a pest that causes high economic losses. It is thus among the primary candidates for genome sequencing. But this species genome is about 50 % larger than that of L. migratoria, and although next-generation sequencing currently allows sequencing large genomes, sequencing it would mean a greater challenge. The chromosome sizes and markers provided here should not only help planning the sequencing project and guide the assembly but would also facilitate assigning assembled linkage groups to actual chromosomes.

Evidence of Bos javanicus x Bos indicus hybridization and major QTLs for birth weight in Indonesian Peranakan Ongole cattle

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

Complex sex chromosome system in Eigenmannia sp. (Pisces, Gymnotiformes)

Chromosomes of Eigenmannia sp. (7 males and 15 females) collected from the Tietê River in Botucatu (SP, Brazil) were examined from gill, kidney and testicular cells. The diploid chromosome number in males was 2n=31 and in females, 2n=32. In both sexes the number of chromosomal arms was 40. The difference in diploid number was due to the fusion of two acrocentrics. Mitotic and meiotic studies suggested that one of the fused acrocentrics was the Y chromosome. The sex-determining mechanism in Eigenmannia sp. could therefore be XX, AA in the female and X, \-YA A in the males. One of the males presented 2n=30 chromosomes due to the occurrence of another fusion of acrocentrics. C-banding analysis of the mitotic chromosomes revealed constitutive heterochromatin in the centromeric regions of all acrocentrics. However, small metacentrics were C-band negative. The YA chromosome is C-band negative except for a small amount of heterochromatin in the centromeric region. The nucleolar organizer region as identified by Ag-staining is present in the interstitial region of chromosome pair No. 10. © 1984 Dr W. Junk Publishers.