Mitochondria, plastids and DNA inheritance

fzestabr at fzestabr at
Mon Feb 14 12:05:39 EST 1994

Dear Jim

: 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?

Plastids are a group of related organelles that share some common 
	1. a small unique genome
	2. Have a double membrane

I am a plant person and I remember that plastids develope from 
proplastids which are present in meristematic cells and then depending on 
the differentiated status of the cell the the proplastids develope into 
specific types of plastids, for example: choloplasts, etioplasts, 
chromoplasts, leuocplasts. These types of plastids are specialized in 
function. So I think that plastid is just a generic word, although 
several people when they use the word plastid are referring specifically 
to cholorplasts. I don't know how this works with animal cells.

By the way what is P. zonal? 

In plant cells, it is thought that all sperm cells lose their plastids 
and thus have maternal inheritance of plastids. This was the way it was 
at least when I kept up on the subject in the 1980's.


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