Length of tail streamers in barn swallows
Article Abstract:
Natural and sexual selection has an influence on the expression of secondary sexual characters. The flight performance of male barn swallows with altered tail lengths has been studied by Evans, concluding that their outermost tail feathers are mostly the outcome of natural selection. However the experiment did not test the aerodynamic mechanism proposed by Norberg, to account for elongated tail streamers in barn swallows. The tail has some functional use, but the difference between the sexes is crucial to mate choice and evidence suggests that the differing tail lengths are due to sexual selection.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1999
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How 'bad genes' survive
Article Abstract:
The good genes sexual selection theory is not supported by simulations which show that random mating has the same resulting offspring because of mating successes, bringing into question genetic fitness. However, in the seaweed fly, the females mate based on male size which has a highly heritable nature. The ability of the mating of homozygous females with less viable homozygous males to produce heterozygous viable offspring is unusual. Therefore, viability is not a selected characteristic in mating but rather whether the sperm and egg are complementary.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1995
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Pulling the fly's leg
Article Abstract:
Antennapedia (Antp) is not needed to make a leg in flies. Instead, it inhibits the functioning of homothorax, a homeobox gene that determines antennal development. This research has identified the antennal-determining genes and indicated how Antp suppresses their function. It has been shown that the genes are extradenticle and homothorax. Ectopic expression of Meis1, a murine homologue that is functionally equivalent to homothorax, was found to convert the analia into an antenna.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1998
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