Chromosomal Mapping of Repetitive DNAs in the Grasshopper Abracris flavolineata Reveal Possible Ancestry of the B Chromosome and H3 Histone Spreading

Autor(es)

Bueno, Danilo ^[1] ; Palacios-Gimenez, Octavio Manuel ^[1] ; Cabral-de-Mello, Diogo Cavalcanti ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Paulista, UNESP, Inst Biociencias, Dept Biol, Rio Claro, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: PLoS One; v. 8, n. 6 JUN 27 2013.
• Citações Web of Science: 55

Resumo

Supernumerary chromosomes (B chromosomes) occur in approximately 15% of eukaryote species. Although these chromosomes have been extensively studied, knowledge concerning their specific molecular composition is lacking in most cases. The accumulation of repetitive DNAs is one remarkable characteristic of B chromosomes, and the occurrence of distinct types of multigene families, satellite DNAs and some transposable elements have been reported. Here, we describe the organization of repetitive DNAs in the A complement and B chromosome system in the grasshopper species Abracris flavolineata using classical cytogenetic techniques and FISH analysis using probes for five multigene families, telomeric repeats and repetitive C(0)t-1 DNA fractions. The 18S rRNA and H3 histone multigene families are highly variable and well distributed in A. flavolineata chromosomes, which contrasts with the conservation of U snRNA genes and less variable distribution of 5S rDNA sequences. The H3 histone gene was an extensively distributed with clusters occurring in all chromosomes. Repetitive DNAs were concentrated in C-positive regions, including the pericentromeric region and small chromosomal arms, with some occurrence in C-negative regions, but abundance was low in the B chromosome. Finally, the first demonstration of the U2 snRNA gene in B chromosomes in A. flavolineata may shed light on its possible origin. These results provide new information regarding chromosomal variability for repetitive DNAs in grasshoppers and the specific molecular composition of B chromosomes. (AU)

• Processo FAPESP: 11/19481-3 - Contribuições a elucidação do significado biológico de cromossomos B utilizando como modelos Rhammatocerus brasiliensis (Orthoptera) e Haplochromis obliquidens (Teleostei): estrutura, evolução e padrões de modificações em proteínas histônicas
• Beneficiário: Diogo Cavalcanti Cabral de Mello
• Linha de fomento: Auxílio à Pesquisa - Regular
• Processo FAPESP: 11/18028-3 - Isolamento, caracterização e mapeamento cromossômico de sequências repetitivas de DNA em Abracris flavolineata (Acrididae, Ommatolampinae), com ênfase na análise de cromossomos B
• Beneficiário: Danilo Bueno
• Linha de fomento: Bolsas no Brasil - Iniciação Científica