ISSN:
1432-1432
Keywords:
Mitochondrial DNA
;
Anas platyrhynchos
;
Gene order
;
Rate of evolution
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract We sequenced 6,478 by of mitochondrial DNA from Peking duck (Anas platyrhyncos). Eight protein genes, 11 tRNAs, part of the small and large ribosomal subunits, and the control region sequences were compared to homologous chicken sequences. The gene organization in duck and chicken is identical but differs from other vertebrates in the juxtaposition of the tRNAGlu-ND6 genes next to the control region and in the lack of a hairpinlike structure between the genes for tRNAAsn and tRNACys used for light-strand replication. Protein, tRNA, and rRNA genes evolved mainly through base substitutions and small insertions and deletions. Transitions greatly outnumber transversions in the tRNA and rRNA genes, but this bias is not evident in protein genes; the control region has a higher proportion of transversions. The duck and chicken control regions show a high frequency of length mutations. Large A-T-rich nucleotide stretches dispersed across the region between the bidirectional transcription promoter and the heavy-strand replication origin in the chicken are absent in the duck. Sequence elements for heavystrand replication in mammals are conserved in the duck and chicken control regions. Estimates of divergence for ribosomal RNAs and proteins based on total substitutions, transversions, and amino acid replacements show that all the duck/chicken values are lower than the corresponding mammal/mammal (cow, human, mouse) values. If paleontological data suggesting that avian and eutherian ordinal radiation occurred at approximately the same time are correct, this suggests that at great evolutionary distance, rate of mitochondrial DNA evolution in birds is somewhat decelerated compared to mammals.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00175506
Permalink
