The platypus put in its place
Article Abstract:
New research using DNA sequences is casting doubt on the long-held assumption that monotremes are the earliest mammalian lineage, being earlier in date that placental and marsupial mammals. It is now claimed that monotremes can be placed within these other mammals, on the lineage which leads to the marsupials. Particularly important research work in this field has been undertaken at the Arnason laboratory in Sweden, where many complete mitochondrial genomes have been sequenced from a wide range of vertebrates and invertebrates, especially mammals.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1997
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Ribosomal RNA trees misleading?
Article Abstract:
Understanding the early evolution of eukaryotes requires phylogenetic placing of protozoa lacking mitochondria. Relevant studies have relied on the use of small-subunit ribosomal RNA sequences. However, the trees arrived at this way may be misleading. The G+C content of RNA of species ranked by this method varies greatly suggesting error. Furthermore, these trees should be reexamined using amino-acid sequence of conservative proteins such as RNA polymerases.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1993
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Mass survivals
Article Abstract:
A supertree approach was used to analyze the claim that more than 40 avian lineages have survived from before the extinctions at the Cretaceous/Tertiary (K/T) boundary 65 Myr ago. The findings reveal that the pivotal macroevolutionary events in the evolution of existing placental mammals occurred either well before, or well after, the K/T boundary.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 2007
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