Post-embryonic cell lineages of the nematode, Caenorhabditis elegans
[摘要] Thenumberofnongonadalnucleiinthefree-livingsoilnematodeCaenorhabditiselegansincreasesfromabout550inthenewlyhatchedlarvatoabout810inthematurehermaphroditeandtoabout970inthematuremale.Thepatternofcelldivisionswhichleadstothisincreaseisessentiallyinvariantamongindividuals;rigidlydeterminedcelllineagesgenerateafixednumberofprogenycellsofstrictlyspecifiedfates.Theselineagesrangeinlengthfromonetoeightsequentialdivisionsandleadtosignificantdevelopmentalchangesintheneuronal,muscular,hypodermal,anddigestivesystems.Frequently,severalblastcellsfollowthesameasymmetricprogramofdivisions;lineallyequivalentprogenyofsuchcellsgenerallydifferentiateintofunctionallyequivalentcells.Wehavedeterminedthesecelllineagesbydirectobservationofthedivisions,migrations,anddeathsofindividualcellsinlivingnematodes.Manyofthecelllineagesareinvolvedinsexualmaturation.Athatching,thehermaphroditeandmalearealmostidenticalmorphologically;bytheadultstage,grossanatomicaldifferencesareobvious.Someofthesesexualdifferencesarisefromblastcellswhosedivisionpatternsareinitiallyidenticalinthemaleandinthehermaphroditebutlaterdiverge.Inthehermaphrodite,thesecellsproducestructuresusedinegg-layingandmating,whereas,inthemale,theyproducemorphologicallydifferentstructureswhichfunctionbeforeandduringcopulation.Inaddition,developmentofthemaleinvolvesanumberoflineagesderivedfromcellswhichdonotdivideinthehermaphrodite.Similarpostembryonicdevelopmentaleventsoccurinothernematodespecies.
[发布日期] [发布机构]
[效力级别] [学科分类] 生物科学（综合）
[关键词] [时效性]
