FISH 311 Lecture Notes - Lecture 15: Myctophiformes, Serranidae, Gonochorism
23 Feb 2018
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Can very quickly switch between xy and zw systems across species. Hormonally controlled -- based on hormones created by the animal itself. Usually fertilize others, very rarely self-fertilize --> maintains genetic diversity. Larger fish can produce larger or more eggs. Higher premium for size in females than males. Males always have sufficient sperm to fertilize eggs. E. g. bluehead wrasse thalassoma bifasciatum (the process for this species takes two weeks) Become males --> everything changes about the fish --> fins, scales, chromatophores, etc. Activated by sperm of related species -- doesn"t actually become a part of the egg, only activates the egg. Genetic variation is due to random mutation, there is no recombination. Only maternal genome -- only genotype of the mother. Fertilized by sperm of related species -- whatever male happens to fertilize the egg. They can use electric organs to stun prey or defend against predators -- is not.
