From Wikipedia,
the free encyclopedia.
The mitochondrial genome
is the genetic material of the
mitochondria. The
mitochondria are
organelles that reproduce
themselves semi-autonomously when
the
eukaryotic cells that they
occupy divide.
The genetic material forming
the mitochondrial
genome is similar in structure
to that of the
prokaryotic genetic material.
It is formed of a single circular
DNA molecule. Mitochondria are
thought to have arisen from
intracellular bacterial symbiotes;
this is called the
endosymbiotic theory.
The
mitochondria of a
sexually-reproducing animal comes
only from the mother's side. The
mitochondrial DNA of a human being
is essentially the same as that of
his or her mother.
In this way, mitochondrial
genetic diseases can affect both
males and females, but can only be
transmitted by females to their
offspring.
Compared to the
nuclear genome, the
mitochondrial genome possesses
some very interesting features:
- All the genes are carried on
a single circular DNA molecule.
- The genetic material is not
bounded by a nuclear envelope.
- The DNA is not packed with
proteins.
- The genome doesn't contain a
lot of non-coding areas (junk
DNA, or "introns").
- Some codons do not follow
the universal rules in
translation.
- Some bases are considered as
a part of two different genes:
as the last base of a gene and
the first base of the next gene.
See also
