Highly repeated DNA sequences in birds: the structure and evolution of an abundant, tandemly repeated 190-bp DNA fragment in parrots.
ABSTRACT Up to 6.8% of the parrot (Psittaciformes) genome consists of a tandemly repeated, 190-bp sequence (P1) located in the centromere of many if not all chromosomes. Monomer repeats from 10 different psittacine species representing four subfamilies were isolated and cloned. The intraspecific sequence variation ranged from 1.5 to 7%. The interspecific sequence variation ranged from less than 3% between two species of cockatoos to approximately 45% between cockatoos and other parrots. The monomer sequences of all 10 parrot species contained several conserved (> 90%) sequence elements at identical locations within the repeat. A comparison with tandemly repeated DNA sequences in other avian species showed that several of these conserved elements were also present at similar locations within the 184-bp repeat of the Chilean flamingo (Phoenicopterus chilensis), suggesting a great antiquity of the repeat. One of the elements was also found in the tandemly repeated sequences of the crane (Gruidae) and falcon (Falconidae) families. The data were used for the construction of a partial most parsimonious relationship that supports a regional subdivision of the Psittaciformes.
SourceAvailable from: Gilles M Leclerc[Show abstract] [Hide abstract]
ABSTRACT: A highly repetitive DNA sequence family from the genome of the North American Morone has been cloned and characterized. This family, first identified as a HindIII repetitive element, is composed of repeat units that range from 285 to 288 bp in length and comprise approximately 5.5% of the genome. The copy number of the repeat was estimated to be 1.85 × 105 per haploid genome set. Data from Southern blot analyses demonstrated that the HindIII repetitive element was tandemly organized. Sequence analysis of six cloned repeat monomers from each of the four North American Morone species, M. saxatilis, M. chrysops, M. americana, and M. mississippiensis, revealed a high degree of conservation of the monomeric unit. The intraspecific sequence variation ranged from 3.2% to 5.4%. A similar level of variation was detected between cloned monomers from the same individual, suggesting that most of the intraspecies variation may be due to variation among copies of the repeat. The interspecific sequence variation ranged from less than 4.6% between M. americana and M. mississippiensis to approximately 16% between the other Morone species pairs. Phylogenetic analysis of the repetitive element nucleotide sequences indicated that M. americana and M. mississippiensis were more closely related to each other than to any other pairs of Morone species. In addition, we reconstructed the Morone phylogeny using 22 previously described morphologic characters. Congruent relationships were obtained between both sets of data. The data suggest that the genus Morone is composed of two sets of sister taxa, M. saxatilis:M. chrysops and M. americana:M. mississippiensis.Marine Biotechnology 01/1999; 1(2):122-130. DOI:10.1007/PL00011759 · 3.15 Impact Factor
Nature Precedings 01/2011;
[Show abstract] [Hide abstract]
ABSTRACT: Karyotypes were studied in the hooded and carrion crows, their naturally occurred hybrids, the jungle crow, the azure-winged magpie (2n= 80 in all aforementioned birds), and the magpie (2n= 82). Corvine birds of Primorskii Krai were karyotyped for the first time. In addition to the similarity in the diploid chromosome sets, corvine birds were shown to have a similar structure of karyotype: in all studied birds, 14 macrochromosomes (Mchs) classified into three groups according to their size were detected. By karyotype structure, birds belonging to the same genus are similar. Some intergeneric differences are due to a change in the position of centromeres of the largest and sex chromosomes. Karyotypes of interspecific hybrids of crows are remarkable for the presence of heteromorphic (t/st) chromosome pair 2 in some individuals, which apparently does not affect their fecundity. Using differential C-banding, the sex chromosome W in female magpies was identified. In addition, heteromorphism was detected in C-bands of homologs of Mch pair 4 in the hooded crow. In the jungle crow, the azure-winged magpie, and the magpie, bright QH-bands and numerous G-bands were detected on Mchs and on some microchromosomes only. Active Ag-NOR-bands were detected on one macrochromosome pair in the magpie. In all, the karyotype structure of corvine birds is comparable to the basic structural scheme of the karyotype in the order Passeriformes, which confirms the concept of conservatism of the avian karyotype.Russian Journal of Genetics 06/2001; 37(7):796-806. DOI:10.1023/A:1016703127516 · 0.41 Impact Factor