DNA Evidence That Humans & Chimps Share A Common Ancestor: Endogenous Retroviruses
Summary
TLDRThis video explores the evidence for evolution found within our DNA, specifically focusing on endogenous retroviruses. It explains how these viral remnants, shared between humans and chimpanzees, are a unique historical record of past infections. The video demonstrates that the identical locations of these viral sequences in both genomes provide strong evidence for a common ancestor, challenging the fixed species view. The script also highlights the importance of DNA evidence in confirming evolutionary relationships, emphasizing the overwhelming support for evolution in science.
Takeaways
- 𧬠The study of endogenous retroviruses in DNA provides strong evidence for evolution, showing that humans and chimpanzees share a common ancestor.
- π¦ Retroviruses are unique viruses that can insert their genetic material into a host's DNA, becoming a permanent part of the host's genome.
- π¬ DNA evidence, specifically endogenous retroviruses, offers an independent and quantifiable way to test evolutionary relationships, separate from fossil and anatomical studies.
- π§¬π Humans and chimpanzees share a significant number of endogenous retroviruses in identical genomic locations, which is highly unlikely to occur by chance if they did not share a common ancestor.
- π§ͺ Experiments have shown that it is possible to revive extinct viruses from endogenous retrovirus DNA sequences found in the human genome.
- π The human genome contains thousands of endogenous retrovirus segments, which are remnants of past viral infections that have mutated beyond their original function.
- π§¬π By comparing the locations of endogenous retroviruses in human and chimpanzee DNA, scientists can map the unique history of viral infections in our shared ancestry.
- π The high degree of similarity in endogenous retrovirus insertions between humans and chimpanzees supports the evolutionary theory over the fixed species view.
- π§¬π The study of DNA evidence, including endogenous retroviruses, reinforces the overwhelming evidence that humans and other primates are part of a complex and diverse evolutionary history.
- π The concept of evolution is as well-established in science as gravity, with DNA studies providing a significant and independent line of evidence supporting it.
Q & A
What is the significance of endogenous retroviruses in the study of evolution?
-Endogenous retroviruses are significant in the study of evolution because they serve as historical records of past infections suffered by our ancestors. They are like scars in our DNA that can be passed on to descendants, providing evidence of a shared evolutionary history.
How do retroviruses insert their genes into a host's DNA?
-Retroviruses reproduce by inserting their genes directly into a cell's DNA. The host cell then treats the virus DNA as its own, using it to make new viruses and passing it on to future generations when the cell reproduces.
What is the difference between endogenous and exogenous retroviruses?
-Endogenous retroviruses are those that have become a permanent part of a species' genome, often due to infections of germ cells like sperm or egg cells. Exogenous retroviruses, on the other hand, are those that infect a host but do not become integrated into the host's genome.
Why are endogenous retroviruses considered as 'scars' in our DNA?
-Endogenous retroviruses are considered 'scars' because they represent the remnants of past viral infections that have been passed down through generations. These viral sequences are integrated into the host's DNA and can be inherited by offspring.
How does the presence of similar endogenous retroviruses in human and chimpanzee DNA support the theory of evolution?
-The presence of similar endogenous retroviruses in the same locations in both human and chimpanzee DNA suggests a shared evolutionary history. The high degree of similarity and shared insertions imply that these viruses were integrated into the genome before the divergence of human and chimpanzee lineages.
What was the result of the experiment where scientists mutated an endogenous retrovirus in human cells?
-In the experiment, scientists mutated an endogenous retrovirus in human cells and observed that it started producing viruses again, effectively reviving an extinct virus from a DNA sequence found in the human genome.
How many shared endogenous retrovirus insertions were found between humans and chimpanzees in the study mentioned in the script?
-The study found 205 shared endogenous retrovirus insertions out of 214 between humans and chimpanzees, indicating a strong genetic relationship and supporting the theory of common ancestry.
What is the likelihood of humans and chimpanzees having the same virus genes in identical DNA locations by coincidence?
-The likelihood is extremely low, with the chance being less than one in the number of all atoms estimated to exist in the entire observable universe, making it a strong argument against the fixed species view.
How do endogenous retroviruses contribute to the genetic diversity within a species?
-Endogenous retroviruses contribute to genetic diversity by introducing new genetic material into a host's genome. Over time, mutations can give these viral genes new functions, some of which might be beneficial to the host, thus playing a role in evolution.
What is the role of DNA evidence in confirming evolutionary relationships between species?
-DNA evidence, including endogenous retroviruses, provides an independent and quantifiable way to test ideas about evolution. The presence of similar DNA sequences, especially in the form of endogenous retroviruses, supports the concept of shared ancestry and the evolutionary relationships between species.
Outlines
𧬠DNA Evidence for Evolution
The script introduces the concept of evolution through the lens of DNA evidence, specifically focusing on endogenous retroviruses. It explains that these viruses can become a permanent part of an organism's DNA, passed down through generations. The script challenges the fixed species view by highlighting the discovery of a common ancestor between humans and chimpanzees, supported by the study of fossils and DNA. The importance of DNA in establishing family relationships is emphasized, with the human genome project cited as a significant source of evidence for evolution. The script also delves into how retroviruses work, their potential impact on the host, and their role as genetic material for evolutionary processes.
π Shared Retrovirus DNA as Evolutionary Proof
This paragraph delves into the specifics of how endogenous retroviruses serve as evidence for the evolutionary relationship between humans and chimpanzees. It discusses the process of retroviruses integrating into host DNA and the improbability of such events occurring in the same genomic locations across different species unless they share a common ancestor. The script uses the example of the chimp genome to illustrate the significant overlap in retrovirus DNA sequences between humans and chimps, which is highly unlikely to occur by chance. The paragraph concludes by emphasizing the overwhelming evidence supporting the evolutionary connection between the two species, as opposed to the fixed species view.
π Overwhelming DNA Evidence for Human-Chimp Common Ancestry
The final paragraph reinforces the idea that the shared endogenous retrovirus DNA between humans and chimpanzees is not only compelling evidence for a common ancestor but also a testament to the broader evolutionary history of life on Earth. It emphasizes the robustness of the evolutionary theory, comparing its scientific support to that of gravity. The script concludes by acknowledging the contributions of supporters and encouraging viewers to engage with the content, reflecting on our interconnectedness with other species through the lens of evolutionary biology.
Mindmap
Keywords
π‘Endogenous Retroviruses
π‘Evolution
π‘Genome
π‘DNA Evidence
π‘Common Ancestor
π‘Retrovirus
π‘Insertion
π‘Mutation
π‘Genealogy
π‘Fixed Species View
Highlights
Endogenous retroviruses serve as evidence for evolution in human DNA.
Scientists once grouped humans and chimpanzees into the ape family without the concept of evolution.
The discovery of evolution and study of fossils led to the acceptance of a common ancestor for humans and chimps.
Dr. Francis Collins highlighted DNA as an independent, quantifiable way to test evolution theories.
DNA evidence is used in courts and genealogy to determine family relationships.
Retroviruses reproduce by inserting their genes into a host's DNA.
Endogenous retroviruses are viral DNA sequences that have become part of a species' genome.
In mammals, retroviruses usually infect white blood cells, but can also integrate into the germline.
The human genome contains thousands of endogenous retrovirus segments.
Endogenous retroviruses are like historical records of past infections suffered by ancestors.
Experiments have revived extinct viruses from human endogenous retrovirus DNA sequences.
The chimp genome's first draft in 2003 showed incredible similarity to human DNA.
Humans and chimps share the same locations of endogenous retrovirus DNA, suggesting a common ancestor.
The chance of humans and chimps sharing virus genes in identical DNA locations by coincidence is astronomically low.
Humans and chimps share 205 out of 214 specific retrovirus insertions, confirming a common evolutionary history.
The evidence from endogenous retrovirus DNA is compelling for the evolutionary relationship between humans and chimps.
Evolution is as well-established as gravity in science, supported by overwhelming DNA evidence.
Transcripts
[Music]
stated clearly presents
[Music]
evidence for evolution in your own dna
endogenous retroviruses
you probably heard that great apes like
chimpanzees are humankind's closest
living relatives even before evolution
was discovered
scientists studying comparative anatomy
already grouped humans into the ape
family alongside chimpanzees
in those pre-evolution years however the
word
family was often used figuratively many
scientists held a fixed species view
they thought humans and chimpanzees had
been similar yet different
since the dawn of time this changed by
the end of the 1800s
along with the discovery of the process
of evolution the study of fossils
convinced the majority of scientists
that humans and chimps do share a common
ancestor
we really are family today
hundreds of transitional fossils have
been found representing over 20 distinct
groups which blur the line
between humans and chimpanzees that said
some people feel that the study of
fossils is too subjective
is there an independent line of evidence
we can use to double check what we think
we know
from the study of fossils and anatomy dr
francis collins
the man who directed the human genome
project rightfully pointed out that the
study of dna
gives us an entirely independent
quantifiable way to
test our ideas about evolution
instead of simply taking his word for it
here we will examine the evidence
for ourselves it's widely known that dna
is great at revealing family
relationships
in the court of law dna evidence is the
gold standard for determining who the
father is
dna evidence is now widely used in the
study of genealogy to
figure out more distant family
relationships and there are many
independent ways
that dna evidence can be used to reveal
family relationships
even between different species here
we'll zoom in on just one line of dna
evidence
endogenous retrovirus dna shared across
species in this case between humans and
chimpanzees
to understand why retrovirus dna is such
a big deal
let's first take a quick look at what
retroviruses are
a retrovirus is a special type of virus
that reproduces by inserting its genes
directly into a cell's dna the virus
genes become a seamless
permanent part of the host cell's genome
the cell treats the virus dna as if it
were its own
it reads the virus genes using them to
make new viruses
and when the cell copies its own dna
before reproducing
it also copies the virus dna and passes
it on as well
in mammals modern retroviruses usually
infect white blood cells
if however a retrovirus happens to
infect a sperm cell or egg cell and if
that sperm or egg cell ends up
participating in fertilization
the resulting child will have a copy of
virus dna
in every single one of her cells she'll
even pass it on to her kids if she has
children
now you might think that this is a
guaranteed death sentence for the child
but the immune system can sometimes
handle the problem
normal copying errors in virus dna can
also shut a virus down
in these cases a retrovirus insertion
can be thought of as a single
giant mutation for the host as is the
case with all mutations
a retrovirus insertion might have a
negative effect
on the individual that contains it it
might be neutral or
with a bit of luck it could end up being
beneficial
virus genes also act as extra genetic
material that evolution can quote
play with as generations pass on future
mutations can give virus genes new
functions
some of which might happen to be useful
recent studies have found that in at
least one case
it seems that an ancient mammal was
infected with a virus that ended up
aiding the animal in reproduction
many of that early mammal's descendants
humans included
eventually became fully dependent on the
virus gene
we can no longer reproduce without it we
are part virus when a retrovirus becomes
a permanent part of a species dna
whether or not it's functional
scientists call it an endogenous
retrovirus endogenous because it is
inside us
from birth it turns out that the human
genome contains thousands
of endogenous retrovirus segments long
stretches of dna with sequences that
match those of retroviruses
luckily for us none of ours can still
make full-fledged viruses
they have simply mutated too much to
perform their original
virus-y functions okay
so if all of this is news to you it's
probably a lot to take in so let's recap
super quick
before we look at how endogenous
retroviruses act as evidence for
evolution
an endogenous retrovirus is a stretch of
dna found in your dna that
got there when one of your ancestors was
infected by
a retrovirus on rare occasions virus
genes find their way into sperm and egg
cells where they can go on to become a
permanent part
of a species genome your endogenous
retroviruses
act as historical records of past
infections suffered by your ancestors
now at this point you might be asking
how do we know for sure
that genes with similar sequences to
virus genes
actually came from viruses has this been
experimentally demonstrated in several
different cases
yes scientists recently took human cells
incubated in petri dishes and slightly
mutated the dna of one of our endogenous
retroviruses to see if it would start
producing viruses again
sure enough it worked an extinct
virus was revived from a dna sequence
found in our very
own human genome endogenous retroviruses
really are the remaining scars of
ancient virus infections
so how does this all act as evidence
that humans
chimps and other primates really evolved
from a common ancestor
in 2003 the first draft of the chimp
genome was published
overall chimp dna and human dna
sequences are incredibly similar
but unless we dive deeper this fact
alone can't tell us for sure if
evolution
is a better explanation than the fixed
species idea
we already know that humans and chimps
have similar traits if dna codes for
traits we should expect our dna to be
similar as well
right in many cases this is a reasonable
point but
not in the case of endogenous
retroviruses
remember your endogenous retroviruses
show you the unique history of specific
virus infections
suffered by your ancestors they're like
scars in our dna that
an individual acquires during its
lifetime and can pass on to his or her
descendants
but only his or her descendants
here we're looking at maps of human and
chimp chromosomes side by side
chromosomes are the structures in our
cells that contain our dna
if humans and chimps share a common
ancestor and if at least some of the
infections we find in our genome
occurred before
the chimp human split we should find the
same virus genes in the exact same
locations
in both human and chimp genomes
in contrast if humans and chimps are not
related they should not share the same
history of virus infections
now of course it is possible that
throughout history both species
humans and chimps were infected by some
of the same viruses
humans and chimps sometimes get each
other sick today but if
chimps and humans are not related those
virus genes will not be found in
identical locations of both
chimp and human dna this is because when
a retrovirus infects a host
there are many different spots in the
host's genome where it might end up
inserting itself
extensive lab experiments with
retroviruses have found that there are
far more than 10 million possible
insertion spots
in the human genome in other words the
chance of a human and a chimp getting
infected in the exact same spot by the
same specific type of virus
is far less than 1 in 10 million so
you're telling me there's a chance
well it's ridiculously unlikely and it
gets worse fast
if two individuals are both infected
with just 12 of the same viruses
the chance that each of those 12
inserted themselves into the exact same
dna locations in both hosts
is less than one in the number of all
the atoms estimated to exist
in the entire observable universe
to get a rough idea of how many
insertions are shared
between humans and chimps researchers
scanned both of our genomes looking for
a type of retrovirus they knew
was common in humans they found 211
insertions in the human genome
and 208 in chimpanzees
to figure out if any of these insertions
are in the same locations in both
humans and chimps they compared the
unique flanking dna sequences on either
side
of each insertion if you think of the
virus as a scar
the flanking sequences are the healthy
bits of tissue
around the scar that tell you where the
scar is located
they found that we share not just one
not just
12 but 205
insertions 205 out of 214
for this particular virus group this
makes perfect sense if we consider the
evolutionary view of life
the 205 shared viruses were inserted
sometime before the chimp human split
the six insertions unique to humans and
the three unique to chimps
either represent insertions that happen
after the split or
they represent deletion mutations that
removed a few viruses
in just one lineage after the chimp
human split
in contrast if we want to believe the
fixed species view
we're forced to conclude that these
viruses are simply shared by coincidence
when we do the math even making sure to
account for the nine viruses not
shared by the two species the chance of
this happening by coincidence
is less than one in this crazy number
right here
this evidence should be enough for even
the most reluctant yet
rational person to carefully set aside
the fixed
species view endogenous retrovirus dna
alone
is more than enough to independently
confirm what we already knew
from the study of fossils that said what
we've seen here is just the tip of the
iceberg
there are many other lines of dna
evidence available
together they demonstrate beyond all
reasonable doubt that humans
and chimpanzees did evolve from a common
ancestor
we are
family
are part of this very complicated
amazing evolutionary history uh we
are related to those other animals
especially
animals like non-human primates like the
chimpanzees
we are directly descended from a common
ancestor the evidence for that is
overwhelming
that evolutionary mechanism by which
life
has spread across this planet and all of
its amazing diversity
over something like 4 billion years is
about as well established as anything i
know in science
so if somebody wants to tell you well
evolution is just a theory and
it'll probably go away someday it's
about as likely to go away as gravity
is it is extremely well supported and
particularly so by the study of dna
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clearly
so long for now stay curious
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