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From: pell@boulder.Colorado.EDU (Anthony Pelletier)
Newsgroups: sci.bio
Subject: Re: Dumb Questions about Mitochondria
Message-ID: <1910@sigi.Colorado.EDU>
Date: Sat, 15-Aug-87 12:49:51 EDT
Article-I.D.: sigi.1910
Posted: Sat Aug 15 12:49:51 1987
Date-Received: Sun, 16-Aug-87 11:23:39 EDT
References: <52@citcom.UUCP>
Sender: news@sigi.Colorado.EDU
Reply-To: pell@boulder.Colorado.EDU (Anthony Pelletier)
Organization: University of Colorado, Boulder
Lines: 39

In article <52@citcom.UUCP> jack@citcom.UUCP (Jack Waugh) writes:
>Which species have mitochondria?
>
>Do mitochondria always have their own DNA and hence
>genetic line independent of nuclear DNA?
>
>In sexually reproducing species, do the mitochondrial
>genes always come from the mother (I understand that
>this is the case for humans).

I might start by suggesting you check a decent biology text for the details
(such as Mol. Bio. Of The Cell: Alberts, Bray, Lewis, Raff, Roberts et. al.).

But the simple answers:  All eukariotes have mitochondria.  This includes
any multicellular organism and alot of unicellular ones such as yeast and
cilliates.  Loosely speaking, those organisms that do not have mito's are
bacteria.

All mitochondria thus studied have their own DNA.  All gene-products of the
mitochondrial genome are used in the mito.  But far from all the proteins
used in the mito come from there.  Most are encoded in the nucleus, made
in the cytoplasm and transported to the mitochondria.

I believe that in all cases known, sexually-produced offspring get their
mitochondria from one parent or the other.  This is true of chloroplast
DNA as well.  The phrase "from their mother" might not apply.
It would be hard to come up with a good reason to call
one yeast "male" and the other "female."  In many metazoans, the 
female gamete is usually much larger than the male gamete.  This may
explain why the "mother's" mitochondia are inhereted.  But it does not
explain the cases where two cells of more-or-less identical size fuse
to form a zygote and the offspring inheret mito DNA from only one of them
(as is the case for Chlamydomonas--an algae).  there are models to
explain this.  

Happy reading.
Tony Pelletier
Molecular etc. Biology
Boulder, Co. 80309-0347