Why sequence the manatee genome?

| 37 Comments
By Gaylen Rathburn, via Wikimedia Commons


I was excited to learn today that there is genome sequence for the West Indian manatee (Trichechus manatus)!! A friend wondered why I was so excited, asking, “Is it evolutionarily interesting?”

Well, first off, I’ve always been fascinated with manatees: they are so defenseless, and yet grow so large that they are rarely predated on. They are, however, especially susceptible to human-made water vessels. I am excited for their genome because I’ve always loved them. But, they are also pretty evolutionarily awesome.


1. Manatees are more closely related to elephants than they are to dolphins or whales.
The manatee and the bottlenosed dolphin are approximately 100 million years diverged from each other. The manatee is classified under the Afrotheria, which also includes elephants, hyraxes, and aardvarks, while the dolphin is classified as Laurasiatheria, which also includes the red panda, hippos, horses, rhinoceros, and bears. You can click on the links above for more detailed lists of the species included in each group.

Although about 100 million years separate manatees from dolphins, the manatee and elephant are only separated by about 61 million years. Unlike dolphins, but like elephants, manatees have toenails:

By Fritz Geller-Grimm, via Wikimedia Commons


2. Manatees convergently (independently) evolved the ability to live under water
Unlike other mammals that live primarily in the water (whales and dolphins), the manatee (and dugong) does not breath air through a blowhole on top of its head. Instead, manatees breath through their nostrils. How cool is that?

By Rusty Clark from Merrit Island FL via Wikimedia Commons

Additionally, manatees independently evolved flippers and wide tails.

Manatees also convergently lost most of their hair (although this isn’t unique to water-dwelling mammals as many terrestrial mammals lost most of their hair too, including pigs, naked mole rats, and humans). I wonder whether similar genes are involved (disrupted?) to result in the loss of hair across these mammals?

3. Manatees have a much lower metabolic rate than expected for their body mass.
Manatees are fairly sedentary, and have a low metabolic rate (0.36 times the predicted rate for placental mammals). Dolphins have a much higher metabolic rate, but a similar expected lifespan as manatees (approximately 50-60 years, to my understanding). So, it will be fascinating to investigate how genomes differ between fspecies with similar generation times, but very different metabolic rates.

37 Comments

And why do they look like that? Do they really think other manatees look hot?

Glen Davidson

If we could only peer into a manatee’s mind…

There was a recent paper on genes involved in hair loss in cetaceans.

Characterization of hairless (Hr) and FGF5 genes provides insights into the molecular basis of hair loss in cetaceans http://www.ncbi.nlm.nih.gov/pmc/art[…]/PMC3608953/

Toenails! I never knew that.

Thanks for the reference pngarrison.

It will be interesting to compare genomes in order to elucidate the mechanisms whereby different mammalian lineages have independently returned to the aquatic lifestyle. Just another example of evo devo and comparative genomics in action.

My wife was in the water with some manatees in Florida years sgo. Imagine a garden slug the size of a refrigerator…and about as lively.

pngarrison said:

There was a recent paper on genes involved in hair loss in cetaceans.

Characterization of hairless (Hr) and FGF5 genes provides insights into the molecular basis of hair loss in cetaceans http://www.ncbi.nlm.nih.gov/pmc/art[…]/PMC3608953/

Cool! Will be very interesting to see if it is the same mutation (or more likely gene) in manatees.

Paul Burnett said:

My wife was in the water with some manatees in Florida years sgo. Imagine a garden slug the size of a refrigerator…and about as lively.

I am totally okay with that. It’s part of why I find them so fascinating.

Moreover, I would be perfectly content to lounge in the FL water with some manatees. Maybe read a book, and enjoy doing nothing. I haven’t done that in… too long.

Melissa asked:

Why sequence the manatee genome?

4. Because it is there.

Sequence the manatee genome because it hasn’t been done before. Do it for the sheer joy of scientific discovery! Carry out the research because we know that the results will be useful someday.

Reason 1-3 will be useful to obtain funding. But - sequence the manatee genome just to find out what’s in their DNA.

You guys are all assuming that manatees have DNA that can be sequenced. On the Theory of Intelligent Design, it is just as likely that manatees were intelligently designed with RNA genes, or with something not based on the usual four (or five) bases, so there might be problems sequencing. What’s the probability that manatees were intelligently designed to be like the rest of life?

Carl Drews said:

Melissa asked:

Why sequence the manatee genome?

4. Because it is there.

Sequence the manatee genome because it hasn’t been done before. Do it for the sheer joy of scientific discovery! Carry out the research because we know that the results will be useful someday.

Reason 1-3 will be useful to obtain funding. But - sequence the manatee genome just to find out what’s in their DNA.

I completely agree!

But, it also needs to be done with high enough coverage & accurately assembled, which takes lots of time, energy & money.

Human hairlessness has been attributed to neoteny (we’re flat-faced, too, like baby chimps); in pigs and rats it looks more like physical environment adaptation, so yeah, it’ll be interesting to see if similar genes are involved.

Manatees , to this YEC, are indeed adapted land creatures that took to the seas after the flood. Their original kind is unknown . The idea of biological relationship to elephants is entirely based on minor like traits in morphology or genetics equally based on extrapolation of present like genes.

The interesting point brought up is about convergent evolution. Indeed evolutionists must invoke this to explain why manatees have traits that unrelated creatures have. In fact its unlikely by any reasoning. Rather they have them from triggers in the body that give like traits. Just like people have like colour though from separate environmental causes. The idea of lucky mutations coming along to create very like flippers and tail as elsewhere in creatures is just asking too much.

Byers, just out of idle curiosity, for I know that in the unlikely event of any answer at all, it will be neither cogent nor coherent, but:

How is it possible to believe that manatees “are indeed adapted land creatures” and that “the idea of lucky mutations…is just asking too much”, both at the same time?

becuz it is much thusly and not top be considered. especialy i further in the far of theg of coarse. Clear to elsewheres pairwise being?

(Sorry, I used one capital appropriately).

DS said:

becuz it is much thusly and not top be considered. especialy i further in the far of theg of coarse. Clear to elsewheres pairwise being?

(Sorry, I used one capital appropriately).

thanks DS, your last two posts have cracked me up!

Cool that they have toenails!

The most important reason for sequencing the manatee genome is to compare it to the elephant genome, when that is sequenced.

It would be thrilling to see how the ERVs align. More death to creationism.

Dave Luckett said:

Byers, just out of idle curiosity, for I know that in the unlikely event of any answer at all, it will be neither cogent nor coherent, but:

How is it possible to believe that manatees “are indeed adapted land creatures” and that “the idea of lucky mutations…is just asking too much”, both at the same time?

Lucky mutations is too much of impossibility by its mechanism claims. Yet there is other mechanisms that are going on to explain diversity within small timelines. People differences are the great case for these mechanisms. Explain the people and one has explained most of it.

diogeneslamp0 said:

The most important reason for sequencing the manatee genome is to compare it to the elephant genome, when that is sequenced.

It would be thrilling to see how the ERVs align. More death to creationism.

Not only how ERVs (endogenous retroviruses) compare between the elephant and manatee, but perhaps also many other independent lines of molecular evidence like transposons (LINE insertions and SINE insertions), pseudogenes, measuring genetic redundancy within otherwise highly conserved genes (like for cytochrome c protein), etc, etc.

Yes indeed, more nails in the coffin of anti-evolutionism. Not that a mind force-fed on bronze-age authoritarianism can see this, though.

Sigh. Cogency and coherence. Prediction confirmed.

I think this word-salad means that Byers rejects the ideas of natural selection and of deep time, but paradoxically, not evolution itself. Not that what he uses for thought is actually coherent.

He thinks that evolution happens, but it’s more like what happens when humans breed animals, except God does the selecting. He also thinks it happens quickly - far more quickly, taking far fewer generations, than evolutionary theory predicts, and so takes thousands, not millions or tens of millions of years.

The first part of this - divine selection - is pure omphalos. It looks like the environment is selecting, but it’s really God, because, well, it is. Because I say so, and you can’t prove it isn’t.

The second part is simply contrary to demonstrable fact. Mutation rates are measurable, have been measured in many species, and are known and knowable. The dateable fossil record confirms them, as a cross-check. The Byers idea that a land-dwelling mammal could evolve into a manatee in the course of a few thousand years is simply ridiculous.

yEs lucky mutations is to much to be believing inwardswise. insteadly the intelligencia of man atees is no doubted to be responding to every aquatic protuberances. yEt there is other mechanisms of which i am not to be saying becuz explaining peoples explains allmostly in the majority of instantaneousness. likewise for man atees

Robert Byers said:

Dave Luckett said:

Byers, just out of idle curiosity, for I know that in the unlikely event of any answer at all, it will be neither cogent nor coherent, but:

How is it possible to believe that manatees “are indeed adapted land creatures” and that “the idea of lucky mutations…is just asking too much”, both at the same time?

Lucky mutations is too much of impossibility by its mechanism claims. Yet there is other mechanisms that are going on to explain diversity within small timelines. People differences are the great case for these mechanisms. Explain the people and one has explained most of it.

And really, why can’t everyone just see that?

Or understand it?

Glen Davidson

Dave Luckett said:

The Byers idea that a land-dwelling mammal could evolve into a manatee in the course of a few thousand years is simply ridiculous.

Not just “a few thousand years”, but a few hundred years. Remember, Noah’s flood happened in 2304 BC, give or take a few years. And, no wild animal has been observed to change appreciably within the span of recorded history (*). Assuming that manatee’s are related to elephants, and that such animals mature in about 15 years, Byers is claiming that a land animal took to the water after Noah’s flood, lost it’s hind legs completely, and turned it’s front feet into flippers all in less that 50 generations.

Yet he claims that evolution is impossible, and that species are immutable.

(*) Of course, the notion of “recorded history” is a bit problematical for Creationists. Noah’s flood happened in 2304 BC, while an unbroken record of written history begins in Egypt in about 3200 BC. While Egyptian records are pretty clear about the annual flooding of the Nile (one of their central religions depended upon it), the Egyptians didn’t seem have to noticed the world wide flood in the middle of the Old Kingdom, at the height of their pyramid building.

Scott F said:

Dave Luckett said:

The Byers idea that a land-dwelling mammal could evolve into a manatee in the course of a few thousand years is simply ridiculous.

Not just “a few thousand years”, but a few hundred years. Remember, Noah’s flood happened in 2304 BC, give or take a few years. And, no wild animal has been observed to change appreciably within the span of recorded history (*). Assuming that manatee’s are related to elephants, and that such animals mature in about 15 years, Byers is claiming that a land animal took to the water after Noah’s flood, lost it’s hind legs completely, and turned it’s front feet into flippers all in less that 50 generations.

Yet he claims that evolution is impossible, and that species are immutable.

(*) Of course, the notion of “recorded history” is a bit problematical for Creationists. Noah’s flood happened in 2304 BC, while an unbroken record of written history begins in Egypt in about 3200 BC. While Egyptian records are pretty clear about the annual flooding of the Nile (one of their central religions depended upon it), the Egyptians didn’t seem have to noticed the world wide flood in the middle of the Old Kingdom, at the height of their pyramid building.

No. The flood happened about 2400 BC. There is no problem with great biological change. people are at least evidence of this. I agree there is great mechanisms for biological change. yet not the impossibility of mutation being selected on over non existent timelines in a clumsy happanchance. Marine mammals all adapted to the empty seas after the flood and so great mecahanism is within biology. Thats fine. We just care about biblical boundaries because they are the truth and no evidence of nature exists to say otherwise. I know most YEC thinkers wouldn’t say marine mammals are adated land creatures but they are not right about everything.

No evidence of nature exists to say otherwise? Really? Really? And exactly how would you know this sir?

Robert Byers said:

The flood happened about 2400 BC.

That is a lie, Robert Byers. Or, if you prefer, a delusion. The proposition is false. There is not the slightest reason to believe it.

While Egyptian records are pretty clear about the annual flooding of the Nile (one of their central religions depended upon it), the Egyptians didn’t seem have to noticed the world wide flood in the middle of the Old Kingdom, at the height of their pyramid building.

Oh, they were probably in de Nile about it.

Robert Byers said: We just care about biblical boundaries

I’d be interested in citations from the Bible about biological boundaries.

TomS said:

Robert Byers said: We just care about biblical boundaries

I’d be interested in citations from the Bible about biological boundaries.

There are none. See this page on Biblical Kinds and look at my two Conclusions. Or search for the strings “bound” and “barrier” on that page.

Carl Drews said:

TomS said:

Robert Byers said: We just care about biblical boundaries

I’d be interested in citations from the Bible about biological boundaries.

There are none. See this page on Biblical Kinds and look at my two Conclusions. Or search for the strings “bound” and “barrier” on that page.

Interesting. Thank you for your work, but I think that you are too generous to “baraminology”. You assume that the word min is an actual word in Biblical Hebrew, that it is a noun, and that it has a referent. Because the word only occurs in a fixed context, usually translated “after his/their kind”, it might be just some obscure idiomatic expression. In addition, there is no reason to believe that “kind”, if it does refer to something, refers to a group of living things; that any living thing belongs to one and only one “kind”; that a living thing belongs to the same “kind” over its lifetime (for example: does a caterpillar change ‘kind” when it becomes a butterfly?; does a clean animal change its “kind” when it becomes unclean? does an animal become of a diffeent “kind” with seasonal change?); or that the descendant of one “kind” of animal also belongs to that “kind”. Even if “kind” does refer to an inherited category, it might be something like a subspecies; maybe different breeds of cattle or different color-patterns in sheep and goats.

I would suggest that a thorough treatment of the expression “after his/their kind” should also examine the Hebrew preposition “after”: l’.

Also does “after its kind” mean all descendants indefinitely, or just the next generation? As I understand it, a change of species in one (or a few) generations is very rare (hybridization or polyploidy (how do you spell that?) might cause it.

Henry J said:

While Egyptian records are pretty clear about the annual flooding of the Nile (one of their central religions depended upon it), the Egyptians didn’t seem have to noticed the world wide flood in the middle of the Old Kingdom, at the height of their pyramid building.

Oh, they were probably in de Nile about it.

Thanks, Henry J, for this. I was about to send it all to the BW, but this, this is worth keeping. :)

Henry J said:

While Egyptian records are pretty clear about the annual flooding of the Nile (one of their central religions depended upon it), the Egyptians didn’t seem have to noticed the world wide flood in the middle of the Old Kingdom, at the height of their pyramid building.

Oh, they were probably in de Nile about it.

This is a good point for creationists. Off thread but quickly since we use the written and oral histories of numerous people groups as evidence for a historical flood THEN the absence in Egypt makes our case. if there was no flood then indeed ancient peoples should have no memory but if it was true they should. most have this memory closest to the flood year where written material is found. Oral histories from tribes never affected by other peoples also attest to the flood. The rare case like the Egyptians can be seen as simply a forgotten history due to the positive virtue of the flooding nile and a extensive wriiten history drowning out the past.

Uh-huh. Flood legends from people who experienced catastrophic local flooding is evidence of a world-wide flood. Absence of flood legends from people who didn’t is also evidence for a world-wide flood.

This’ll end up on the BW, and very right, too.

Robert, my dear poor deluded boy. You have once again missed the point. *IF* the story of Noah’s flood were true, then there would be no Middle Kingdom of Egypt, the written history of Egypt would not exist, and we would see unmistakeable evidence of the Great Pyramids having been under water.

1. But the Middle Kingdom of Egypt *did* exist. The Middle Kingdom consisted of several hundred thousand people. In order for there to be hundreds of thousands of people (in Egypt alone) just 200 years after the Flood, then every single female descendant of Noah’s family must have given birth to 3 live children every year for 20 years of her life, for over two hundred years. And that only counts the population of Egypt, not to mention the rest of Mesopotamia, or China. Not only did Noah’s children live for hundreds of years, they also bred like rabbits.

2. The fact that the written history doesn’t mention a global flood doesn’t mean that the flood was “forgotten”. The fact is that we have an *unbroken* physical written history spanning the centuries around 2400 BC. It doesn’t matter what words they wrote. Most of the written “history” we have is of the little things of life: how much grain was received on this date; what king died; what king was born; what battles were fought, and who won; how many cows were sold; how much olive oil was transported. Very little of that talks about water or floods. But here’s the point. *IF* the Flood story were true, then there would be no people left alive to write these things down!!. The fact that there were people, alive, writing things down during the year of the flood, and after the year of the flood, is by itself physical proof that those living people existed. They were not under water, and they were not dead.

3. The Pyramids of Giza were built before 2400 BC. There is no physical evidence that the Great Pyramids were ever under water.

Well what did you expect? This from the same mind that told you that preventing creationism from being taught in public schools was censorship but that it wasn’t censorship if enough people voted to have evolution banned from public schools! Now an entire civilization that not only survived a “world-wide” flood, in fact never even noticed a “world-wide” flood, is evidence that there was a “world-wide” flood! Literally unbelievable. If Robert had two neurons to rub together you would swear he was a POE. As it is, not so much.

Robert Byers said:

Henry J said:

While Egyptian records are pretty clear about the annual flooding of the Nile (one of their central religions depended upon it), the Egyptians didn’t seem have to noticed the world wide flood in the middle of the Old Kingdom, at the height of their pyramid building.

Oh, they were probably in de Nile about it.

This is a good point for creationists. Off thread but quickly since we use the written and oral histories of numerous people groups as evidence for a historical flood THEN the absence in Egypt makes our case. if there was no flood then indeed ancient peoples should have no memory but if it was true they should. most have this memory closest to the flood year where written material is found. Oral histories from tribes never affected by other peoples also attest to the flood. The rare case like the Egyptians can be seen as simply a forgotten history due to the positive virtue of the flooding nile and a extensive wriiten history drowning out the past.

Byers, you’re dumber than a plateful of hair.

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This page contains a single entry by M. Wilson Sayres published on December 2, 2013 10:04 PM.

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