The upcoming, October 21, issue of Nature contains much content on genomics and evolution - here are two interesting abstracts; not yet indexed for Pubmed, I've linked to the abstracts at the journal webpage (hopefully won't cause access problems):
An
exciting article describes the sequencing of a pufferfish with the smallest known vertebrate genome, and subsequent comparative genomic analysis attempting to reconstruct the "ancestral vertebrate karyotype". It contains some interesting chromosome evolution models that I hadn't see before (with such specificity).
Nature 431, 946 - 957 (21 October 2004)
Genome duplication in the teleost fish Tetraodon nigroviridis reveals the early vertebrate proto-karyotype.
Olivier Jallion, et.al.
Tetraodon nigroviridis is a freshwater puffer fish with the smallest known vertebrate genome. Here, we report a draft genome sequence with long-range linkage and substantial anchoring to the 21 Tetraodon chromosomes. Genome analysis provides a greatly improved fish gene catalogue, including identifying key genes previously thought to be absent in fish. Comparison with other vertebrates and a urochordate indicates that fish proteins have diverged markedly faster than their mammalian homologues. Comparison with the human genome suggests 900 previously unannotated human genes. Analysis of the Tetraodon and human genomes shows that whole-genome duplication occurred in the teleost fish lineage, subsequent to its divergence from mammals. The analysis also makes it possible to infer the basic structure of the ancestral bony vertebrate genome, which was composed of 12 chromosomes, and to reconstruct much of the evolutionary history of ancient and recent chromosome rearrangements leading to the modern human karyotype.
The issue also contains a
brief communication on evolution of flight, with discussion of a four-winged intermediate in the evolution of flight in birds:
Nature 431, 925 (21 October 2004)
Palaeontology: Leg feathers in an Early Cretaceous bird
Fucheng Zhang and Zhonghe Zhou
Here we describe a fossil of an enantiornithine bird from the Early Cretaceous period in China that has substantial plumage feathers attached to its upper leg (tibiotarsus). The discovery could be important in view of the relative length and aerodynamic features of these leg feathers compared with those of the small 'four-winged' gliding dinosaur Microraptor and of the earliest known bird, Archaeopteryx. They may be remnants of earlier long, aerodynamic leg feathers, in keeping with the hypothesis that birds went through a four-winged stage during the evolution of flight.
Enjoy!
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