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Mitogenomic analyses of eutherian relationships
1Division of Evolutionary Molecular Systematics, University of Lund, Lund, Sweden.ulfur.arnason@gen.lu.se
Cytogenetic and Genome Research
|November 20, 2002
Summary
Phylogenetic analyses of mammalian mitochondrial genomes reveal that hedgehogs are distinct from other lipotyphlans. This study redefines mammalian evolutionary relationships and ancient divergence times.
Area of Science:
- Evolutionary Biology
- Genomics
- Mammalian Phylogenetics
Background:
- Accurate evolutionary phylogenies are crucial for testing hypotheses.
- Mammalian classification has historically relied on morphological and limited genetic data.
Purpose of the Study:
- To reconstruct mammalian evolutionary history using complete mitochondrial genomes.
- To resolve phylogenetic relationships among eutherian orders and primate divergences.
Main Methods:
- Phylogenetic analyses of 67 complete mammalian mitochondrial (mt) genomes.
- Analyses conducted at both amino acid (aa) and nucleotide (nt) levels (first and second codon positions).
Main Results:
- Erinaceomorpha (hedgehogs) identified as the sister group to all other eutherians, rendering traditional Lipotyphla polyphyletic.
- Two major eutherian clades identified: Cetferungulata and the African clade.
- Confirmed sister-group relationship between Anthropoidea and Dermoptera, making Primates paraphyletic.
- Molecular estimates suggest eutherian orders originated in the Cretaceous (70-100 million years before present).
- Primate divergences, including Homo and Pan, estimated to have occurred ~10 million years before present.
Conclusions:
- Mammalian mitochondrial genome data provides robust phylogenetic insights.
- Revises understanding of major mammalian clades and their evolutionary timelines.
- Highlights the need for re-evaluation of traditional mammalian orders based on molecular data.
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