Mitochondria, Plastids and DNA inheritance

nicola fidler btbirch at brolga.cc.uq.oz.au
Sat Feb 19 00:33:29 EST 1994


cummins at possum.murdoch.edu.au (Jim Cummins) writes:
Plastid is the general term for a group of plant cell organelles, some of which are green and called chloroplasts. Others may be coloured like those in flower petals and called chromoplasts. There are also proplastids which are the
uncommitted predecessors of all types in a particular plant.

Q1: By "unique" I presume you mean DNA which is different from that in the
nucleus. If so, then yes. Functions such as DNA replication are principally
controlled by proteins which are usually encoded in the organelle's own DNA
.This is very similar to that in bacterial cells and supports the prokaryotic
origin theory of organelles.

Q2:in some plant species (can't remember which at the moment), there is
evidence that cytoplasmic inheritance is paternal.

Hope that clears up the fog a little.

Nick F. Botany, Uni of Qld, Australia. 

>" Direct evidence of plastid DNA and mitochondrial DNA in sperm cells
>in relation to biparental inheritance of organelle DNA in Pelargonium
>zonale by fluorescence electron microscopy" A Kuroiwa,et al  Eur J 
>Cell Biol  (1993) 62: 307-313
>According to this paper's abstract both plastids and mitochondria
>contain DNA and may show  biparental inheritance. 

>Two questions
>(1) Is there any other evidence that plastids contain unique DNA?
>(2) Is there any other evidence of biparental inheritance of
>non-nuclear DNA?  I thought maternal inheritance was obligatory. 

>PS (I'm sure not to be alone in this :^)) What is a plastid?
>Jim Cummins                   
>School of Veterinary Studies
>Murdoch University
>Western Australia 6150  Tel +61-9-360 2668 Fax +61-9-310 4144
>"An inordinate fondness for Beetles"

>Jim Cummins                   
>School of Veterinary Studies
>Murdoch University
>Western Australia 6150  Tel +61-9-360 2668 Fax +61-9-310 4144
>"An inordinate fondness for Beetles"



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