1,721,185 research outputs found
Organization and Evolution of Metazoan Mitochondrial Genomes
No full textAlthough almost certainly derived from the same ancestral progenitor, mitochondrial genomes have followed multiple and different evolutionary pathways in various taxa; it shows great variability in terms of structure, gene content, organization and mode of expression in different organisms. Nevertheless, the evolutionary process has been frozen, in several senses, in the Metazoa, particularly with respect to genome size and gene content. As mitochondrial (mt) DNA is a relatively small, abundant and easy to isolate molecule, it has been particularly favoured as a molecular evolutionary marker and the nucleotide sequence from a large number of species has now been determined(http://www.ncbi.nlm.nih.gov/genomes/ORGANELLES/mztax_short.html). Metazoan mtDNA is, in general, a single circular molecule, although some cnidarians (Medusozoa) are known to possess atypical linear mt DNA. It is characterized by a compact arrangement, the constancy of gene content and the presence of a single noncoding region. With the exception of the replication origin region(s), the genome is saturated with intron‐less genes, lacking intronic sequence, which are often contiguous and sometimes slightly overlapping or separated by only a few nucleotides
A novel method for estimating substitution rate variation among sites in a large dataset of homologous DNA sequences
No full textMITOCHONDRIAL RIBOSOMES FROM RAT LIVER .2. CHARACTERIZATION OF RNA EXTRACTED FROM MITOCHONDRIAL RIBOSOMES
No full textCITOCHROME-OXIDASE SUBUNIT III FROM ARBACIA LIXULA. DETECTION OF FUNCTIONAL CONSTRAINTS BYCOMPARISON WITH HOMOLOGOUS SEQUENCES
No full textActivity of messenger RNA extracted from rat liver mitochondria. 1) Stimulation of an E. coli cell-free system by mitochondrial RNA containing poly A
No full textMitochondrial DNA detection and copy number determination in the spermatozoa of the sea-urchin Arbacia lixula
No full textSystematic and evolutionary studies in mammals: The contribution of the mitochondrial genome
No full textMolecular data represent an important source of information for systematic and evolutionary studies; ideally this information should be evaluated together with data coming from other approaches (e.g., paleontological and morphological), since the molecular approach is limited by the availability of suitable homologous sequences, and these may be taxonomically informative only if they derive from speciation events (i.e., orthologous) and not from gene duplications (i.e., paralogous). This study focuses on the availability of sequences from the vertebrate class of Mammalia. The results show a strong bias in databases as, for some orders, little or no sequences are stored. For nuclear genes it is often difficult to discriminate between orthologous and paralogous ones. Therefore we advise the use in comparative studies of entire mitochondrial genomes which are easy to sequence and only contain orthologous genes. We report here the genetic organization of the mitochondrial DNA in mammals. In addition a phylogenetic tree of mammals, obtained by using the complete mitochondrial genomes of 23 species, is reported here
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