RESUMO
The presence of repetitive elements can create serious problems for sequence analysis, especially in the case of homology searches in nucleotide sequence databases. Repetitive elements should be treated carefully by using special programs and databases. In this paper, various aspects of SINE (short interspersed repetitive element) identification, analysis and evolution are discussed.
Assuntos
Filogenia , Elementos Nucleotídeos Curtos e Dispersos , Animais , Sequência de Bases , Biologia Computacional , Bases de Dados Factuais , Evolução Molecular , Marcadores Genéticos , Humanos , Mamíferos/genética , Modelos Genéticos , Dados de Sequência Molecular , Alinhamento de Sequência/estatística & dados numéricos , Análise de Sequência/estatística & dados numéricos , SoftwareRESUMO
In analysis of the repeats from the mink X Chromosome (Chr), we have identified a B2-like repetitive sequence of 195 base pairs (bp) flanked by short direct repeats of 14 bp. It contains regions homologous to the split intragenic RNA polymerase III promoter and a 3' A-rich region followed by an oligo(dA) sequence. A feature of the repeat is the presence of a perfect polypyrimidine tract 22 bp in length absent from the known Alu- and Alu-like sequences. Alignment of the mink B2-like sequence and mouse B2-consensus sequence allowed us to estimate their similarity as 55%. The repeat is present in 1-2 x 10(5) copies per mink genome and 2-4 x 10(3) copies per X Chr. In situ hybridization analysis demonstrated a similar distribution pattern of the B2-like repeat along the length of all the mink chromosomes including the X. We also observed the presence of mink B2-like hybridizable sequence in the genomes of other Carnivora species.
