Dynamical evolution of Jupiter's Trojan asteroids

Article Abstract:

The orbits of swarm asteroids called Trojans which are orbiting the sun with the same mean semi-major axis as Jupiter but lead or trail Jupiter in its orbit are not stable indefinitely. The gravitational forces of the giant planets have reduced the swarms'outer boundaries over time. The Trojan swarms of Jupiter are slowly dispersing and about 200 escaped asteroids with diameters greater than one km must be added to the list of dynamically unstable structures in the Solar System.

Asteroids

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Episodic adaptive evolution of primate lysozymes

Article Abstract:

Colobine monkeys are distinct from other primates because they possess the digestive enzyme lysozyme, which functions similarly in cows. A study of the phylogeny of primates show that the amino acids may have evolved under positive darwinian selection. However, a comparison of sequences reveals that the mammalian lysozyme appears to have evolved under negative selection. This shows that adaptive episodes are eclipsed in comparison of sequences.

Analysis, Genetic aspects, Monkeys, Chemical evolution, Molecular evolution, Lysozyme

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Role of mutator alleles in adaptive evolution

Article Abstract:

Most mutations are likely to be damaging so the mutation rate is usually at a low level. However, up to 1% of isolates from natural bacteria are 'mutator' clones with a high rate of mutation. Computer forecasts, set to typical values for Escherichia coli cultures, suggest that mutator genes can accelerate adaption.

Models, Escherichia coli, Variation (Biology), Genetics, Microbial mutation, Genetic research, Mutation breeding

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