DNA Evidence That Humans & Chimps Share A Common Ancestor: Endogenous Retroviruses

Summary

This 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

• 🧬 The study of endogenous retroviruses in DNA provides strong evidence for evolution, showing that humans and chimpanzees share a common ancestor.
• 🦠 Retroviruses are unique viruses that can insert their genetic material into a host's DNA, becoming a permanent part of the host's genome.
• 🔬 DNA evidence, specifically endogenous retroviruses, offers an independent and quantifiable way to test evolutionary relationships, separate from fossil and anatomical studies.
• 🧬🐒 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.
• 🧪 Experiments have shown that it is possible to revive extinct viruses from endogenous retrovirus DNA sequences found in the human genome.
• 🌐 The human genome contains thousands of endogenous retrovirus segments, which are remnants of past viral infections that have mutated beyond their original function.
• 🧬📊 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.
• 🔍 The high degree of similarity in endogenous retrovirus insertions between humans and chimpanzees supports the evolutionary theory over the fixed species view.
• 🧬🌐 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.
• 🌟 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

00:00

🧬 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.

05:03

🐒 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.

10:05

🌐 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.

Keywords

💡Endogenous Retroviruses

Endogenous retroviruses are segments of viral DNA that have been integrated into the genome of a host organism. They are considered 'endogenous' because they are present within the host from birth. In the context of the video, endogenous retroviruses serve as evidence for evolution, as they can be found in the DNA of humans and other primates, suggesting a shared ancestry. The video explains that these viral remnants are like 'scars' in our DNA, marking past infections that have been passed down through generations.

💡Evolution

Evolution is the process by which species of organisms change over time through genetic variation and natural selection. The video uses the study of endogenous retroviruses as a means to provide evidence for evolution, particularly the shared evolutionary history between humans and chimpanzees. It emphasizes that the presence of similar endogenous retroviruses in both species suggests a common ancestor, which is a fundamental concept in evolutionary theory.

💡Genome

The genome refers to the complete set of genetic information of an organism, including all of its genes. In the video, the human genome is discussed in relation to the presence of endogenous retroviruses. The comparison of the human and chimpanzee genomes is used to demonstrate the high degree of similarity, which supports the idea of a shared evolutionary history.

💡DNA Evidence

DNA evidence is used in the video to refer to the genetic material that can be analyzed to determine relationships between species. It is highlighted as an 'independent, quantifiable way' to test ideas about evolution, separate from the study of fossils and anatomy. The video explains that DNA evidence, specifically endogenous retroviruses, can provide a clear and objective record of evolutionary relationships.

💡Common Ancestor

A common ancestor is a species from which two or more other species have evolved. The video script discusses the concept of a common ancestor between humans and chimpanzees, suggesting that the shared presence of endogenous retroviruses in both species is evidence of this relationship. This is a key point in the argument for evolution, as it implies a shared evolutionary history.

💡Retrovirus

A retrovirus is a type of virus that can insert its genetic material into the DNA of a host cell, becoming a permanent part of the host's genome. The video explains that when a retrovirus infects a germ cell (sperm or egg), the resulting offspring will inherit this viral DNA. This can lead to the presence of endogenous retroviruses in the DNA of many individuals within a species.

💡Insertion

In the context of the video, 'insertion' refers to the process by which a retrovirus integrates its DNA into the host's genome. The video discusses how the location of these insertions can be a unique identifier of a species' evolutionary history. Shared insertions between humans and chimpanzees suggest a common ancestor, as the chance of the same virus inserting in the same location in two unrelated species is astronomically low.

💡Mutation

Mutation refers to changes in the DNA sequence that can occur spontaneously or be induced by external factors. In the video, mutations are discussed in the context of how they can alter the function of endogenous retroviruses over time. Some mutations may render the virus non-functional, while others might give the virus new functions, contributing to the genetic diversity that is a hallmark of evolution.

💡Genealogy

Genealogy is the study of family ancestry and descent. The video mentions that DNA evidence is now widely used in genealogy to determine distant family relationships. This concept is extended to the study of species, where DNA evidence, including endogenous retroviruses, can reveal evolutionary relationships between different species.

💡Fixed Species View

The fixed species view is an outdated belief that species are unchanging and have remained the same since their creation. The video contrasts this view with the theory of evolution, using the evidence of endogenous retroviruses to argue against the idea of fixed species. The presence of similar viral DNA in humans and chimpanzees challenges the notion that species are static and unchanging.

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

this animation was funded by colt correa

and by our supporters at patreon.com

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helping us out so we can make more of

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over on patreon.com forward slash stated

clearly

so long for now stay curious