RESUMO
Cytochrome P450 partial sequences were isolated by PCR using genomic DNA from two hymenopteran insects of agronomical importance, Trichogramma cacoeciae, a parasitoid wasp, and Apis mellifera, the honeybee. Four new P450 genes were identified: one honeybee gene belongs to the CYP4 family and was named CYP4G11; the three other genes were from Trichogramma and belong to the CYP4 family (CYP4G12) and to a novel family, the CYP48 one (CYP48A1 and CYP48A2). The four genes contain a short intron (72-95 bp) at the same position as already described for other insect species. The two genes CYP48A1 and CYP48A2 have a supernumary intron (57-71 bp) upstream the first one. Only the two CYP4 genes were constitutively transcribed, at a high level for CYP4G12 and at a low level for CYP4G11. No expression was observed for CYP48A1 and CYP48A2.
Assuntos
Abelhas/enzimologia , Abelhas/genética , Sistema Enzimático do Citocromo P-450/genética , Genes de Insetos , Vespas/enzimologia , Vespas/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Clonagem Molecular , Primers do DNA/genética , Expressão Gênica , Íntrons , Dados de Sequência Molecular , Filogenia , Homologia de Sequência de AminoácidosRESUMO
An AluI family of highly reiterated nontranscribed sequences has been found in the genome of the honeybee Apis mellifera. This repeated sequence is shown to be present at approximately 23,000 copies per haploid genome constituting about 2% of the total genomic DNA. The nucleotide sequence of 10 monomers was determined. The consensus sequences is 176 nucleotides long and has an A + T content of 58%. There are clusters of both direct and inverted repeats. Internal subrepeating units ranging from 11 to 17 nucleotides are observed, suggesting that it could have evolved from a shorter sequence. DNA sequence data reveal that this repeat class is unusually homogeneous compared to the other class of invertebrate highly reiterated DNA sequences. The average pairwise sequence divergence between the repeats is 2.5%. In spite of this unusual homogeneity, divergence has been found in the repeated sequence hybridization ladder between four different honeybee subspecies. Therefore, the AluI highly reiterated sequences provide a new probe for fingerprinting in A. m. mellifera.
Assuntos
Abelhas/genética , Sequência Conservada , Sequências Repetitivas de Ácido Nucleico , Animais , Sequência de Bases , Southern Blotting , DNA , Desoxirribonucleases de Sítio Específico do Tipo II , Dados de Sequência Molecular , Filogenia , Polimorfismo de Fragmento de RestriçãoRESUMO
The phytoparasitic nematode, Bursaphelenchus xylophilus, contains an unusually abundant satellite DNA which constitutes up to 30% of its genome. It is represented as a tandemly repeated MspI-site-containing sequence with a monomeric unit of 160 bp. Thirteen monomers were cloned and sequenced. The consensus sequence is 62% A+T-rich, with the presence of direct and inverted repeat clusters. Monomers of the sequence are very similar, showing on average 3.9% divergence from the calculated consensus. The results suggest that some homogenizing mechanism is acting to maintain the homogeneity of this satellite DNA despite its abundance and that it is not transcribed.
Assuntos
DNA Satélite/genética , Genes de Helmintos/genética , Nematoides/genética , Animais , Sequência de Bases , Clonagem Molecular , Sequência Consenso , DNA Recombinante , DNA Satélite/química , Desoxirribonuclease HpaII , Desoxirribonucleases de Sítio Específico do Tipo II , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Plasmídeos , Sequências Repetitivas de Ácido Nucleico , Mapeamento por Restrição , Análise de Sequência de DNA , Homologia de Sequência do Ácido NucleicoRESUMO
To have a better understanding of the evolutionary history of mobile elements within the nematodes, we examined the distribution and the conservation of homologues to transposable elements from Caenorhabditis elegans (Tc1, Tc2, Tc3, Tc4, Tc5, and FB1) in 19 nematode species belonging to the class Secernentea. Our results show that Tc1 elements display a distribution restricted to the family Rhabditidae with poor conservation. The Tc2 and FB1 homologous elements have the same patchy distribution within the Rhabditidae. They were only found in Caenorhabditis and in Teratorhabditis. The Tc3 element is widely distributed among nematode species. Tc3 homologous elements are present in the majority of the Rhabditidae but also in two genera within the family Panagrolaimidae, and in Bursaphelenchus, which belongs to the order Aphelenchida. Tc4 and Tc5 homologues show the most limited distribution of all tested elements, being strictly limited to C. elegans. These data indicate that in some cases, the distribution of transposable elements in the nematode cannot be explained by strict vertical transmission. The distribution of Tc3, Tc4, and Tc5 suggests that horizontal transmission may have occurred between reproductively isolated species during their evolutionary history.
