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John 1:12
12 But as many as received
him, to them gave he power
to become the sons of God,
even to them that believe
on his name:
©2001 Timothy G. Standish
Endosymbiosis and the
Origin of Eukaryotes:
Are mitochondria really just
bacterial symbionts?
Timothy G. Standish, Ph. D.
©2001 Timothy G. Standish
Outline
Mitochondria - A very brief overview
Endosymbiosis - Theory and evidence
Archaezoa - Eukaryotes lacking mitochondria
Gene expression - Mitochondrial proteins
coded in the nucleus
Mitochondrial genetic codes
Gene transport - Mitochondria to nucleus
Conclusions
©2001 Timothy G. Standish
Mitochondria
Mitochondria are organelles found in most
eukaryotic organisms.
The site of Krebs cycle and electron transport
energy producing processes during aerobic
respiration
Are inherited only from the mother during sexual
reproduction in mammals and probably all other
vertebrates.
Because of their mode of inheritance genetic
material found in mitochondria appears to be useful
in determining the maternal lineage of organisms.
©2001 Timothy G. Standish
Mitochondria
Outer membrane
Matrix
Inner membrane
mtDNA
Inter membrane space
©2001 Timothy G. Standish
Extranuclear DNA
Mitochondria and chloroplasts have their own DNA
This extranuclear DNA exhibits non-Mendalian inheritance
Recombination is known between some mt and ctDNAs
Extranuclear DNA may also be called cytoplasmic DNA
Generally mtDNA and ctDNA is circular and contains genes
for multimeric proteins some portion of which are also
coded for in the nucleus
Extra-nuclear DNA has a rate of mutation that is
independent of nuclear DNA
Generally, but not always, all the RNAs needed for
transcription and translation are found in mtDNA and
ctDNA, but only some of the protein genes
©2001 Timothy G. Standish
mtDNA
Mitochondrial DNA is generally small in animal cells,
about 16.5 kb
In other organisms sizes can be more than an order of
magnitude larger
Plant mtDNA is highly variable in size and content with
the large Arabidopsis mtDNA being 200 kb.
The largest known number of mtDNA protein genes is 97
in the protozoan Riclinomonas mtDNA of 69 kb.
“Most of the genetic information for mitochondrial
biogenesis and function resides in the nuclear geneome,
with import into the organelle of nuclear DNA-specified
proteins and in some cases small RNAs.” (Gray et
al.,1999)
©2001 Timothy G. Standish
Endosymbiosis
©2001 Timothy G. Standish
Origin of Eukaryotes
Two popular theories presupposing naturlaism seek to
explain the origin of membrane bound organelles:
1 Endosymbiosis to explain the origin of mitochondria and
chloroplasts (popularized by Lynn Margulis (Margulis, 1981)
2 Invagination of the plasma membrane to form the
endomembrane system
©2001 Timothy G. Standish
Origin of Eukaryotes
Two popular theories presupposing naturlaism seek to
explain the origin of membrane bound organelles:
1 Endosymbiosis to explain the origin of mitochondria and
chloroplasts (popularized by Lynn Margulis (Margulis, 1981)
2 Invagination of the plasma membrane to form the
endomembrane system
Mitochondria
©2001 Timothy G. Standish
Origin of Eukaryotes
Two popular theories presupposing naturlaism seek to
explain the origin of membrane bound organelles:
1 Endosymbiosis to explain the origin of mitochondria and
chloroplasts (popularized by Lynn Margulis (Margulis, 1981)
2 Invagination of the plasma membrane to form the
endomembrane system
Endoplasmic
Mitochondria
Reticulum
Nucleus
Chloroplast
Golgi
Body
©2001 Timothy G. Standish
Origin of Eukaryotes
Two popular theories presupposing naturlaism seek to
explain the origin of membrane bound organelles:
1 Endosymbiosis to explain the origin of mitochondria and
chloroplasts (popularized by Lynn Margulis (Margulis, 1981)
2 Invagination of the plasma membrane to form the
endomembrane system
Endoplasmic Reticulum
Mitochondria
Nucleus
Chloroplast
Golgi Body
©2001 Timothy G. Standish
How Mitochondria Resemble Bacteria
Most general biology texts list ways in which
mitochondria resemble bacteria. Campbell et al.
(1999) list the following:
Mitochondria resemble bacteria in size and morphology.
They are bounded by a double membrane: the outer thought
to be derived from the engulfing vesicle and the inner from
bacterial plasma membrane.
Some enzymes and inner membrane transport systems
resemble prokaryotic plasma membrane systems.
Mitochondrial division resembles bacterial binary fission
They contain a small circular loop of genetic material
(DNA). Bacterial DNA is also a circular loop.
They produce a small number of proteins using their own
ribosomes which look like bacterial ribosomes.
Their ribosomeal RNA resembles eubacterial rRNA.
©2001 Timothy G. Standish
How Mitochondria Don’t
Resemble Bacteria
Mitochondria are not always the size or morphology of
bacteria:
– In some Trypanosomes (ie Trypanosoma brucei) mitochondria
undergo spectacular changes in morphology that do not
resemble bacteria during different life cycle stages
(Vickermann, 1971)
– Variation in morphology is common in protistans,
“Considerable variation in shape and size of the organelle can
occur.” (Lloyd, 1974 p1)
Mitochondrial division and distribution of mitochondria
to daughter cells is tightly controlled by even the simplest
eukaryotic cells
©2001 Timothy G. Standish
How Mitochondria Don’t
Resemble Bacteria
Circular mtDNA replication via D loops is different from
replication of bacterial DNA (Lewin, 1997 p441).
mtDNA is much smaller than bacterial chromosomes.
Mitochondrial DNA may be linear, examples include:
Plasmodium, C. reinhardtii, Ochromonas, Tetrahymena,
Jakoba (Gray et al., 1999).
Mitochondrial genes may have introns which eubacterial
genes typically lack (these introns are different from
nuclear introns so they cannot have come from that
source) (Lewin, 1997 p721, 888).
The genetic code in many mitochondria is slightly
different from bacteria (Lewin, 1997).
©2001 Timothy G. Standish
Archaezoa
©2001 Timothy G. Standish
Giardia - A “Missing Link”?
The eukaryotic parasite Giardia has been
suggested as a “missing link” between
eukaryotes and prokaryotes because it lacks
mitochondria (Friend, 1966, Adam, 1991)
thus serving as an example of membrane
invagination but not endosymbiosis
Giardia also appears to lack smooth
endoplasmic reticulum, peroxisomes and
nucleoli (Adam, 1991) so these must have
either been lost or never evolved
©2001 Timothy G. Standish
A Poor “Missing Link”
As a “missing link” Giardia is not a strong
argument due to its parasitic life cycle which
lacks an independent replicating stage
outside of its vertebrate host
– Transmission is via cysts excreted in feces
followed by ingestion
– As an obligate parasite, to reproduce, Giardia
needs other more derived (advanced?)
eukaryotes
Some other free living Archaezoan may be a
better candidate
©2001 Timothy G. Standish
Origin of Gardia
Gardia and other eukaryotes lacking mitochondira and
plastids (Metamonada, Microsporidia, and Parabasalia )
have been grouped by some as “Archezoa” (CavalierSmith, 1983; Campbell et al., 1999 pp524-6)
This name reflects the belief that these protozoa split from
the group which gained mitochondria prior to that event.
The discovery of a mitochondrial heat shock protein
(HSP60) in Giardia lamblia (Soltys and Gupta, 1994) has
called this interpretation into question.
Other proteins thought to be unique to mitochondria,
HSP70 (Germot et al., 1996), chaperonin 60 (HSP60)
(Roger et al., 1996; Horner et al., 1996) and HSP10 (Bui
et al, 1996) have shown up in Gardia’s fellow Archezoans
©2001 Timothy G. Standish
Origin of Archezoa
The authors who reported the presence of mitochondrial
genes in amitochondrial eukaryotes all reinterpreted
prevailing theory in saying that mitochondria must have
been present then lost after they had transferred some of
their genetic information to the nucleus.
The hydrogenosome, a structure involved in carbohydrate
metabolism found in some Archezoans (Muller, 1992), is
now thought to represent a mitochondria that has lost its
genetic information completely and along with that loss,
the ability to do the Krebs cycle (Palmer, 1997).
Alternative explanations include transfer of genetic
material from other eukaryotes and the denovo production
of hydrogenosomes by primitive eukaryotes.
©2001 Timothy G. Standish
Origin of Archezoa:
Mitochondrial Aquisition
©2001 Timothy G. Standish
Origin of Archezoa:
Gene Transfer and Loss
mtGenes
Lost
genetic
material
©2001 Timothy G. Standish
Origin of Archezoa:
Option 1 - Mitochondrial Eukaryote Production
©2001 Timothy G. Standish
Origin of Archezoa:
Option 2 - Mitochondrial DNA Loss/
Hydrogenosome production
Hydrogenosome
©2001 Timothy G. Standish
Origin of Archezoa:
Option 2A - Mitochondria/Hydrogenosome Loss
©2001 Timothy G. Standish
Gene Transport
©2001 Timothy G. Standish
“All in all then, the host nucleus
seems to be a tremendous
magnet, both for organellar
genes and for endosymbiotic
nuclear genes.”
Palmer, 1997
©2001 Timothy G. Standish
Steps in Mitochondrial Acquisition:
The Serial Endosymbiosis Theory
Fusion of Rickettsia with either a
nucleus containing Archazoan or an
archaebacterium
Rickettsia
Host Cell
Primitive
eukaryote
DNA
reduction/transfer
to nucleus
Ancestral eukaryote
(assuming a nucleus)
©2001 Timothy G. Standish
Steps in Mitochondrial Acquisition:
The Hydrogen Hypothesis
Fusion of proteobacterium with an
archaebacterium
Hydrogen
producing
proteobacterium
Hydrogen
requiring
archaebacterium
DNA
reduction/transfer
nucleus production
Ancestral eukaryote
With nucleus containing both
archaebacterium and
proteobacterium genes
©2001 Timothy G. Standish
Phylogeny
Bacteria
Microsporidia,
and Parabasalia
Metamonada Eukaryota
Bacteria
mtDNA Hydrogenosome/
loss mitochondria
loss
mtDNA
loss
Gene transfer
Cell fusion
Origin of Life
©2001 Timothy G. Standish
Timing of Gene Transfer
Because gene transfer occurred in eukaryotes lacking
mitochondria, and these are the lowest branching
eukaryotes known:
Gene transfer must have happened very early in the
history of eukaryotes.
The length of time for at least some gene transfer
following acquisition of mitochondria is greatly
shortened.
No plausible mechanism for movement of genes from
the mitochondira to the nucleus exists although
intraspecies transfer of genes is sometimes invoked to
explain the origin of other individual nuclear genes.
©2001 Timothy G. Standish
Gene
Expression
©2001 Timothy G. Standish
Cytoplasmic Production of
Mitochondrial Proteins
Mitochondria produce only a small subset of the
proteins used in the Krebs cycle and electron
transport. The balance come from the nucleus
As mitochondrial geneomes vary spectacularly
between different groups of organisms, some of
which may be fairly closely related, if all came
from a common ancestor, different genes coding
for mitochondrial proteins must have been passed
between the nucleus and mitochondria multiple
times
©2001 Timothy G. Standish
The Unlikely Movement of Genes
Between Mitochondria and the Nucleus
Movement of genes between the mitochondria
and nucleus seems unlikely for at least two
reasons:
1 Mitochondria do not always share the same
genetic code with the cell they are in
2 Mechanisms for transportation of proteins
coded in the nucleus into mitochondria seem to
preclude easy movement of genes from
mitochondria to the nucleus
©2001 Timothy G. Standish
Protein Production
Mitochondria and Chloroplasts
Cytoplasm
Nucleus
G
AAAAAA
Export
Mitochondrion
Chloroplast
©2001 Timothy G. Standish
Protein Production
Mitochondria and Chloroplasts
Cytoplasm
Nucleus
Mitochondrion
Chloroplast
©2001 Timothy G. Standish
Protein Production
Mitochondria
Outer membrane
Inner membrane
Matrix
Inter membrane space
©2001 Timothy G. Standish
Protein Production
Mitochondria
Leader sequence
binding receptor
ATP
ATP
P +ADP
Matrix
MLSLRQSIRFFKPATRTLCSSRYLL
P +ADP
Outer membrane
Inner membrane
Inter
membrane
space
©2001 Timothy
G. Standish
Protein Production
Mitochondria
Leader sequence
binding receptor
Outer membrane
Peptidease
cleaves off
the leader
Inner membrane
Matrix
Inter
membrane
space
©2001 Timothy
G. Standish
Protein Production
Mitochondria
Leader sequence
binding receptor
Outer membrane
Inner membrane
Matrix
Inter
membrane
space
©2001 Timothy
G. Standish
Protein Production
Mitochondria
Leader sequence
binding receptor
Outer membrane
Inner membrane
Matrix
Inter
membrane
space
©2001 Timothy
G. Standish
Protein Production
Mitochondria
Leader sequence
binding receptor
Outer membrane
Hsp60
Hsp60
Matrix
Chaperones
Inner membrane
Inter
membrane
space
©2001 Timothy
G. Standish
Protein Production
Mitochondria
Leader sequence
binding receptor
Outer membrane
Inner membrane
Matrix
Mature protein
Inter
membrane
space
©2001 Timothy
G. Standish
M
L
S
L Polar
R
I
Q
S
NonR
polar
F
First 12 residues are sufficient for
transport to the mitochondria
F
K
A
P
R
T
L Polar
C
R
P
S
S
Y
L
Neutral Non-polar
Polar
Basic
Acidic
MLSLRQSIRFFKPATRTLCSSRYLL
Recognized by peptidase?
T
Yeast Cytochrome C
Oxidase Subunit IV Leader
This leader does not resemble other
eukaryotic leader sequences, or other
mtProtein leader sequences.
Probably forms an a helix
This would localize specific classes of
amino acids in specific parts of the helix
There are about 3.6 amino acids per turn
of the helix with a rise of 0.54 nm per turn
©2001 Timothy G. Standish
Yeast Cytochrome C1 Leader
Charged leader sequence signals
for transport to mitochondria
First cut
MFSNLSKRWAQRTLSKTLKGSKSAAGTATSYFEKLVTAGVAAAGITASTLLYANSLTAGA-------------Uncharged second leader sequence signals for transport
across inner membrane into the intermembrane space
Second cut
Cytochrome c functions in electron transport and is
thus associated with the inner membrane on the
intermembrane space side
Cytochrome c1 holds an iron containing heme
group and is part of the B-C1 (III) complex
C1 accepts electrons from the Reiske protein and
passes them to cytochrome c
Neutral Non-polar
Polar
Basic
Acidic
©2001 Timothy G. Standish
Protein Production
Mitochondria
Outer membrane
Inner membrane
Matrix
Inter membrane space
©2001 Timothy G. Standish
Protein Production
Mitochondria
ATP
Leader sequence
binding receptor
P +ADP
Outer membrane
ATP
P +ADP
Peptidease
cleaves off
the leader
Matrix
Inner membrane
Inter
membrane
space
©2001 Timothy
G. Standish
Protein Production
Mitochondria
Leader sequence
binding receptor
Outer membrane
Inner membrane
Matrix
Inter
membrane
space
©2001 Timothy
G. Standish
Protein Production
Mitochondria
Leader sequence
binding receptor
Outer membrane
Inner membrane
Matrix
Inter
membrane
space
©2001 Timothy
G. Standish
Protein Production
Mitochondria
Leader sequence
binding receptor
Outer membrane
Inner membrane
Matrix
Inter
membrane
space
©2001 Timothy
G. Standish
Protein Production
Mitochondria
Leader sequence
binding receptor
Outer membrane
Inner membrane
Matrix
Inter
membrane
space
©2001 Timothy
G. Standish
Protein Production
Mitochondria
Leader sequence
binding receptor
Outer membrane
Inner membrane
Peptidease
cleaves off the
second leader
Matrix
Inter
membrane
space
©2001 Timothy
G. Standish
Protein Production
Mitochondria
Leader sequence
binding receptor
Outer membrane
Inner membrane
Matrix
Inter
membrane
space
©2001 Timothy
G. Standish
Protein Production
Mitochondria
Leader sequence
binding receptor
Outer membrane
Inner membrane
Matrix
Inter
membrane
space
©2001 Timothy
G. Standish
Protein Production
Mitochondria
Note that chaperones are not
involved in folding of proteins
in the inter membrane space
and that they exist in a low pH
environment
Leader sequence
binding receptor
Outer membrane
Inner membrane
Mature protein
Matrix
Inter
membrane
space
©2001 Timothy
G. Standish
Alternative Mechanism
1.
2.
There are actually two theories about how the
leader operates to localize mtproteins in the inter
membrane space:
The first, as shown in the previous slides,
involves the whole protein moving into and then
out of the matrix
The alternative theory suggests that once the first
leader, which targets to the mitochondria is
removed, the second leader prevents the protein
from ever entering the matrix so it is transported
only into the inter membrane space.
©2001 Timothy G. Standish
Building a Minimally Functional
Nuclear Mitochondrial Gene
Given that a fragment of DNA travels from the
mitochondria to the nucleus and is inserted into the
nuclear DNA
Nuclear DNA
Control Sequence Signal Sequence
Mitochondrial Gene
Control Sequence
Additional hurdles may
include:
Signal Sequence
Resolution of problems resulting from
differences
Mitochondrial
Gene
between mitochondrial and nuclear introns
Resolution of problems resulting from differences
between mitochondiral and nuclear genetic codes
©2001 Timothy G. Standish
Additional Requirements
In addition to addition of appropriate
control and leader sequences to
mitochondrial genes, the following
would be needed:
Recognition and transport mechanisms
in the cytoplasm
Leader sequence binding receptors
Peptidases that recognize leader
sequences and remove them
©2001 Timothy G. Standish
No Plausible Mechanism Exists
If genes were to move from the mitochondria to the nucleus
they would have to somehow pick up the leader sequences
necessary to signal for transport before they could be
functional
While leader sequences seem to have meaningful portions
on them, according to Lewin (1997, p251) sequence
homology between different sequences is not evident, thus
there could be no standard sequence that was tacked on as
genes were moved from mitochondria to nucleus
Alternatively, if genes for mitochondrial proteins existed in
the nucleus prior to loss of genes in the mitochondria, the
problem remains, where did the signal sequences come
from? And where did the mechanism to move proteins with
signal sequences on them come from?
©2001 Timothy G. Standish
Mitochondrial
Genetic Codes
©2001 Timothy G. Standish
Variation In Codon Meaning
Lack of variation in codon meanings across almost all phyla is
taken as an indicator that initial assignment must have occurred
early during evolution and all organisms must have descended
from just one individual with the current codon assignments
Exceptions to the universal code are known in a few single celled
eukaryotes, mitochondria and at least one prokaryote
Most exceptions are modifications of the stop codons UAA, UAG
and UGA
Organism
Codon/s
Tetrahymena thermophila UAA UAG
A ciliate
Paramecium
UAA UAG
A ciliate
Common Meaning Modified Meaning
Stop
glutamine
Stop
glutamine
Euplotes octacarinatus
UGA
Stop
cysteine
Mycoplasma capricolum
UGA
Stop
tryptophan
Candida
CUG
serine
leucine
A ciliate
A bacteria
A yeast
Neutral Non-polar, Polar
©2001 Timothy G. Standish
AUA=Met
CUN=Thr
Universal
Code
AAA=Asn
AUA=Ile
AAA=Asn
Vertebrates
Insects
Molluscs
Echinoderms
Nematodes
Platyhelmiths
Yeast/
Molds
Plants
Cytoplasm/
Nucleus
Variation in Mitochondrial
Codon Assignment
UGA/G=Stop
NOTE - This would mean
AUA changed from Ile to
Met, then changed back to
AUA=Met
Ile in the Echinoderms
AGA/G=Ser
AAA must have changed from Lys to
Asn twice
UGA=Trp
UGA must have changed to Trp then back to stop
Differences in mtDNA lower the number of tRNAs needed
©2001 Timothy G. Standish
Problems Resulting From
Differences in Genetic Codes
Changing the genetic code, even of the most
simple genome is very difficult.
Because differences exist in the mitochondrial
genomes of groups following changes in the
mitochondrial genetic code, mitochondrial genes
coding differently must have been transported to
the nucleus.
These mitochondrial genes must have been edited
to remove any problems caused by differences in
the respective genetic codes.
©2001 Timothy G. Standish
Behe Goes Beyond
Moustraps
In an essay entitled : Intelligent Design theory as a Tool
for Analyzing Biochemical Systems, Michael Behe
encourages researchers to go beyond “simple”
biochemical systems and to apply Intelligent design
theory to more complex sub-cellular systems. He
specifically poses the question:
“Given that some biochemical systems were designed by
an intelligent agent, and given the tools by which we
came to that conclusion, how do we analyze other
biochemical systems that may be more complicated and
less discrete than the ones we have so far discussed?”
(Behe, 1998 p184)
©2001 Timothy G. Standish
No Modern Examples
Unfortunately for Margulis and S.E.T. [the serial
endosymbiotic theory], no modern examples of prokaryotic
endocytosis or endosymbioses exist . . . She discusses any
number of prokaryotes endosymbiotic in eukaryotes and
uses Bdellovibrio as a model for prokaryotic endocytosis.
Bdellovibrios are predatory (or parasitoid) bacteria that feed
on E. coli by penetrating the cell wall of the latter and then
removing nutrient molecules from E. coli while attached to
the outer surface of its plasma membrane. Although it is
perfectly obvious that this is not an example of one
prokaryote being engulfed by another Margulis continually
implies that it is.
P.J. Whitfield, review of “Symbiosis in Cell Evolution,” Biological
Journal of the Linnean Society 18 [1982]:77-78; p. 78)
©2001 Timothy G. Standish
Conclusions
Presence of mitochondrial genes in nuclear DNA reduces
the window of time available for mitochondrial
acquisition in eukaryotes.
Understanding the structure of mitochondrial genes in
the nucleus and how they are expressed makes the
transfer of genes from protomitochondria to the nucleus
appear complex.
Differences between mitochondrial genetic codes and
nuclear genetic codes adds to the complexity of gene
transfer between mitochondria and nucleus.
As molecular data accumulates, the endosymbiotic origin
of mitochondria appears less probable.
©2001 Timothy G. Standish
Laboratory
©2001 Timothy G. Standish
PCR of Human mtDNA
M
Single nucleotide
polymorphisms are
common in the mtDNA
control region. These
can be used to identify
remains and determine
maternal linage due to
the maternal inheritance
of mitochondria
Single 460 bp mtDNA
control region fragment
which is polymorphic in
sequence, but not size
©2001 Timothy G. Standish
Human mtDNA
0
tRNA Pro
440 bp
fragment
15,971
Left primer
0
16,411
Right
primer
1,260
Control region,
D-Loop,
Or hypervariable region
16,569 bp
©2001 Timothy G. Standish
The Amplified Segment
gaaaaagtct ttaactccac cattagcacc caaagctaag
Attctaattt aaactattct ctgttctttc atggggaagc
agatttgggt accacccaag tattgactca cccatcaaca
accgctatgt atttcgtaca ttactgccag ccaccatgaa
tattgtacgg taccataaat acttgaccac ctgtagtaca
taaaaaccca atccacatca aaaccccctc cccatgctta
caagcaagta cagcaatcaa ccctcaacta tcacacatca
actgcaactc caaagccacc cctcacccac taggatacc
Acaaacctac ccacccttaa cagtacatag Tacataaagc
catttaccgt acatagcaca ttacagtcaa atcccttctc
Gtccccatgg atgacccccc tcagataggg gtcccttgac
caccatcctc cgtga
©2001 Timothy G. Standish
The Amplified Segment
5’ctttaactccaccattagcacccaaagctaag…
5’ttaactccaccattagca3’
3’…tcagataggggtcccttgaccaccatcctccgt
3’ggaactggtggtaggagg5’
Following are what I suspect the primers to be:
– Right Primer 5’ggaggatggtggtcaagg3’ TM 58.80
– Left Primer 5’ttaactccaccattagca3’ TM 49.71
©2001 Timothy G. Standish
The Amplified Segment
5’ctttaactccaccattagcacccaaagctaag…
5’ttaactccaccattagca3’
cc3’
…tcagataggggtcccttgaccaccatcctccgt3’
3’ggaactggtggtaggagg5’
This would up TM and
stabilize 3’ end of the primer
Following are what I suspect the primers to be:
– Right Primer 5’ggaggatggtggtcaagg3’ TM 58.80
– Left Primer 5’ttaactccaccattagca3’ TM 49.71
©2001 Timothy G. Standish
Human mtDNA Genes
Genes in human (for which numbers are given) and
other mammalian mitochondria can be divided into
three groups:
tRNA genes - 22
rRNA genes - 2
Protein coding genes - 13
Total genes = 37
All protein coding genes are involved in respiration
Aside from the coding portion of genes there is
very little additional DNA except in the
approximately 1,200 bp control region
©2001 Timothy G. Standish
Location Strand Length
3307..4263
+ 318
4470..5513
+ 347
5904..7445 + 513
7586..8269
+ 227
8366..8572
+ 68
8527..9207
+ 226
9207..9989
+ 260
10059..10406 + 115
10470..10766 + 98
10760..12139 + 459
12337..14148 + 603
14149..14673 - 174
14747..15883 + 378
Gene
ND1
ND2
COX1
COX2
ATP8
ATP6
COX3
ND3
ND4L
ND4
ND5
ND6
CYTB
Product
NADH dehydrogenase subunit 1
NADH dehydrogenase subunit 2
cytochrome c oxidase subunit I
cytochrome c oxidase subunit II
ATP synthase F0 subunit 8
ATP synthase F0 subunit 6
cytochrome c oxidase subunit III
NADH dehydrogenase subunit 3
NADH dehydrogenase subun 4L
NADH dehydrogenase subunit 4
NADH dehydrogenase subunit 5
NADH dehydrogenase subunit 6
cytochrome b
©2001 Timothy G. Standish
©2001 Timothy G. Standish