http://en.wikipedia.org/wiki/Tetrahymena
As is typical of ciliates, T. thermophilia has two functionally differentiated types of nuclei, the micronucleus and macronucleus.The micronucleus is the germline nucleus; i.e., it contains the DNA information passed down from one sexual generation to the next. The micronucleus is diploid and contains five pairs of chromosomes. The genes of the micronucleus are transcriptionally inert during vegetative growth. The macronucleus is the somatic nucleus, i.e. its genes are actively expressed. However, the macronucleus is propagated only during the vegetative part of the life cycle and is not transmitted from one sexual generation to the next. The macronucleus is polyploid and contains 200-300 autonomously replicating DNA species derived from the five micronuclear chromosomes by site-specific fragmentation.
As is typical of ciliates, T. thermophilia has two functionally differentiated types of nuclei, the micronucleus and macronucleus.The micronucleus is the germline nucleus; i.e., it contains the DNA information passed down from one sexual generation to the next. The micronucleus is diploid and contains five pairs of chromosomes. The genes of the micronucleus are transcriptionally inert during vegetative growth. The macronucleus is the somatic nucleus, i.e. its genes are actively expressed. However, the macronucleus is propagated only during the vegetative part of the life cycle and is not transmitted from one sexual generation to the next. The macronucleus is polyploid and contains 200-300 autonomously replicating DNA species derived from the five micronuclear chromosomes by site-specific fragmentation.
No comments:
Post a Comment