简介：SequencevariationofpartialcytochromebgenesbetweentwoCoiliaspecies,C.ectenesandC.mystus,wasinvestigated.Ofthe402nucleotides,twenty-seven(6.72%)arepolymorphicandallaresynonymoussubstitutions.Atthethirdpositionsofgeneticcondonofcytochromebgene,thetwospeciesshowanextremeanti-Gbias(＜4%)andapronouncedbiastowardsAandC(＞68%).Thereisnoaminoacidsequencedivergencebetweenthepartialcytochromebgenesofthetwospecies,indicatingaclosegeneticrelationshipbetweenthem.Thek-2pgeneticdistanceofpartialcytochromebsegmentofthetwospeciesis0.072,suggestingthatthespecieswereseparated3.6Maago,inthemiddlePliocene.Ourresultrevealsthatthecytochromebgeneisanappropriatemarkerforstudiesofpopulationgeneticstructuresandphylogeographicpatternsofthetwospecies.