# CMI and Whale Leg Genes

**URL:** <https://discourse.peacefulscience.org/t/cmi-and-whale-leg-genes/11676>\
**Category:** Side Conversation\
**Tags:** Article\
**Created:** [September 11, 2020, 6:00pm UTC](https://discourse.peacefulscience.org/t/cmi-and-whale-leg-genes/11676 "2020-09-11T18:00:35Z")\
**Posts on this page:** 20\
**Page:** 1

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**Author:** ![Timothy\_Horton](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/timothy_horton/32/9410_2.png) [@Timothy\_Horton](https://discourse.peacefulscience.org/u/Timothy_Horton)\
**Post date:** [September 11, 2020, 6:00pm UTC](https://discourse.peacefulscience.org/t/cmi-and-whale-leg-genes/11676/1 "2020-09-11T18:00:35Z")

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> [@Two Questions for Paul Price About Genesis and Jesus](https://discourse.peacefulscience.org/t/two-questions-for-paul-price-about-genesis-and-jesus/11674/4):
>
> Let me give you an example of what a feedback article looks like, and if you think it would be possible to achieve what you want in that format.
> 
> [https://creation.com/feedback-archives](https://creation.com/feedback-archives)

I noticed in June 2020 [a Joshua S.] asked CMI a question [Do whales have leg ‘genes’](https://creation.com/whales-and-leg-genes)

> Dr. S: Hats off to your work in showing the flaws of evolution! I wanted to ask: Is there any truth to the claim that whales possess genes for hind legs but are not expressed or are dormant in whales. If this is true how would the creation model explain such a fact? I know that supposed vestigial bones have been shown to be functional but i am asking about supposed leg _genes_ here. Thank You

CMI denied it

> First, the short dry answer: No, whales do not have ‘leg’ genes.

CMI is 100% wrong as usual. Cetaceans as well as other marine mammals do have the unexpressed Tbx4 genes for rear limbs

> [Sequence Variation in the Tbx4 Gene in Marine Mammals](https://www.researchgate.net/profile/Hiroko_Koike/publication/5972548_Sequence_Variation_in_the_Tbx4_Gene_in_Marine_Mammals/links/566a3d7508ae1a797e37a130.pdf)
> 
> Abstract: The amino-acid sequences of the T-domain region of the Tbx4 gene, which is required for hindlimb development, are 100% identical in humans and mice. Cetaceans have lost most of their hindlimb structure, although hindlimb buds are present in very early cetacean embryos. To examine whether the Tbx4 gene has the same function in cetaceans as in other mammals, we analyzed Tbx4  
> sequences from cetaceans, dugong, artiodactyls and marine carnivores. A total of 39 primers were  
> designed using human and dog Tbx4 nucleotide sequences. Exons 3, 4, 5, 6, 7, and 8 of the Tbx4  
> genes from cetaceans, artiodactyls, and marine carnivores were sequenced. Non-synonymous  
> substitution sites were detected in the T-domain regions from some cetacean species, but were not  
> detected in those from artiodactyls, the dugong, or the carnivores. The C-terminal regions  
> contained a number of non-synonymous substitutions. Although some indels were present, they  
> were in groups of three nucleotides and therefore did not cause frame shifts. The dN/dS values for  
> the T-domain and C-terminal regions of the cetacean and artiodactylous Tbx4 genes were much  
> lower than 1, indicating that the Tbx4 gene maintains it function in cetaceans, although full expression leading to hindlimb development is suppressed.

Perhaps @PDPrice can explain why CMI posts such demonstrably wrong information.

ETA: Turns out the Joshua S who asked this at CMI was not our Dr. Swamidass but another Joshua S.

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**Author:** ![Timothy\_Horton](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/timothy_horton/32/9410_2.png) [@Timothy\_Horton](https://discourse.peacefulscience.org/u/Timothy_Horton)\
**Post date:** [September 11, 2020, 8:22pm UTC](https://discourse.peacefulscience.org/t/cmi-and-whale-leg-genes/11676/2 "2020-09-11T20:22:05Z")

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No Creationists here want to comment on this before it scrolls into oblivion? PDPrice?

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**Author:** ![swamidass](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/swamidass/32/3_2.png) [@swamidass](https://discourse.peacefulscience.org/u/swamidass)\
**Post date:** [September 11, 2020, 8:24pm UTC](https://discourse.peacefulscience.org/t/cmi-and-whale-leg-genes/11676/3 "2020-09-11T20:24:20Z")

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> [@Timothy\_Horton](#):
>
> I noticed in June 2020 Dr. Swamidass asked CMI

Hmm. I don’t recall asking this question of them. It must be a different Josh S.

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**Author:** ![Timothy\_Horton](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/timothy_horton/32/9410_2.png) [@Timothy\_Horton](https://discourse.peacefulscience.org/u/Timothy_Horton)\
**Post date:** [September 11, 2020, 8:26pm UTC](https://discourse.peacefulscience.org/t/cmi-and-whale-leg-genes/11676/4 "2020-09-11T20:26:49Z")

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OK thanks. What an interesting coincidence. I’ll correct the OP.

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**Author:** ![scd](https://avatars.discourse-cdn.com/v4/letter/s/6f9a4e/32.png) [@scd](https://discourse.peacefulscience.org/u/scd)\
**Post date:** [September 12, 2020, 5:34pm UTC](https://discourse.peacefulscience.org/t/cmi-and-whale-leg-genes/11676/5 "2020-09-12T17:34:06Z")

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this is very simple: the Tbx4 gene is a multifunctional gene. fishes have it too, but they dont have legs:

> **[Genetic basis of hindlimb loss in a naturally occurring vertebrate model](https://bio.biologists.org/content/5/3/359)**
>
> Here we genetically characterise pelvic finless, a naturally occurring model of hindlimb loss in zebrafish that lacks pelvic fin structures, which are homologous to tetrapod hindlimbs, but displays no other abnormalities. Using a hybrid positional...

thus, CMI are right about this since this isnt a just a “leg gene”.

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**Author:** ![Timothy\_Horton](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/timothy_horton/32/9410_2.png) [@Timothy\_Horton](https://discourse.peacefulscience.org/u/Timothy_Horton)\
**Post date:** [September 12, 2020, 5:46pm UTC](https://discourse.peacefulscience.org/t/cmi-and-whale-leg-genes/11676/6 "2020-09-12T17:46:52Z")

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LOL! Brilliant. So it’s a “limb” gene, not a “leg” gene. 😄

**HINT:** The hind limbs on cetacean terrestrial ancestors were legs.

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**Author:** ![scd](https://avatars.discourse-cdn.com/v4/letter/s/6f9a4e/32.png) [@scd](https://discourse.peacefulscience.org/u/scd)\
**Post date:** [September 12, 2020, 6:26pm UTC](https://discourse.peacefulscience.org/t/cmi-and-whale-leg-genes/11676/7 "2020-09-12T18:26:30Z")

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> [@Timothy\_Horton](#):
>
> The hind limbs on cetacean terrestrial ancestors were legs.

this is a belief. not a fact.

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**Author:** ![T.j\_Runyon](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/t.j_runyon/32/9662_2.png) [@T.j\_Runyon](https://discourse.peacefulscience.org/u/T.j_Runyon)\
**Post date:** [September 12, 2020, 6:42pm UTC](https://discourse.peacefulscience.org/t/cmi-and-whale-leg-genes/11676/8 "2020-09-12T18:42:59Z")

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> [@scd](#):
>
> this is a belief. not a fact.

Wait. What? What are you calling a belief?

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**Author:** ![Rumraket](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/rumraket/32/9328_2.png) [@Rumraket](https://discourse.peacefulscience.org/u/Rumraket)\
**Post date:** [September 12, 2020, 6:44pm UTC](https://discourse.peacefulscience.org/t/cmi-and-whale-leg-genes/11676/9 "2020-09-12T18:44:21Z")

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> [@scd](#):
>
> this is a belief. not a fact.

 ![](https://us1.discourse-cdn.com/flex016/uploads/peacefulscience/original/2X/1/157cd73c3a5c79a6489af94f2db191f32f37aa0c.jpeg)

Yeah no way these mere hind limbs are legs.

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**Author:** ![Timothy\_Horton](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/timothy_horton/32/9410_2.png) [@Timothy\_Horton](https://discourse.peacefulscience.org/u/Timothy_Horton)\
**Post date:** [September 12, 2020, 7:27pm UTC](https://discourse.peacefulscience.org/t/cmi-and-whale-leg-genes/11676/10 "2020-09-12T19:27:04Z")

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> [@scd](#):
>
> > [@Timothy\_Horton](#):
> >
> > The hind limbs on cetacean terrestrial ancestors were legs.
> 
> this is a belief. not a fact.

It’s been confirmed well enough to be considered a scientific fact.

![](https://us1.discourse-cdn.com/flex016/uploads/peacefulscience/original/2X/3/3b534fe5bc9c88984d55ffb6199a5c29ef173fe9.jpeg)

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<div class="post-metadata">

**Author:** ![scd](https://avatars.discourse-cdn.com/v4/letter/s/6f9a4e/32.png) [@scd](https://discourse.peacefulscience.org/u/scd)\
**Post date:** [September 12, 2020, 8:20pm UTC](https://discourse.peacefulscience.org/t/cmi-and-whale-leg-genes/11676/11 "2020-09-12T20:20:14Z")

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> [@Timothy\_Horton](#):
>
> It’s been confirmed well enough to be considered a scientific fact.

you probably mean a scientific theory. and im not sure about the scientific part.

> [@T.j\_Runyon](#):
>
> Wait. What? What are you calling a belief?

something that we cant prove.

> [@Rumraket](#):
>
> Yeah no way these mere hind limbs are legs.

again, you assume that this fossil represent whale ancestor.

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**Author:** ![Rumraket](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/rumraket/32/9328_2.png) [@Rumraket](https://discourse.peacefulscience.org/u/Rumraket)\
**Post date:** [September 12, 2020, 8:28pm UTC](https://discourse.peacefulscience.org/t/cmi-and-whale-leg-genes/11676/13 "2020-09-12T20:28:31Z")

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> [@scd](#):
>
> again, you assume that this fossil represent whale ancestor.

Disregarding the fact that fossils are rarely thought to represent direct ancestors(it’s more likely to be a sister taxon closely related to a direct ancestor), the transitional status of this fossil is not an assumption but an evidentially derived conclusion.

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**Author:** ![scd](https://avatars.discourse-cdn.com/v4/letter/s/6f9a4e/32.png) [@scd](https://discourse.peacefulscience.org/u/scd)\
**Post date:** [September 13, 2020, 5:23am UTC](https://discourse.peacefulscience.org/t/cmi-and-whale-leg-genes/11676/14 "2020-09-13T05:23:45Z")

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> [@Rumraket](#):
>
> the transitional status of this fossil is not an assumption but an evidentially derived conclusion.

we can say the same about design, so there is no real difference.

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**Author:** ![Timothy\_Horton](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/timothy_horton/32/9410_2.png) [@Timothy\_Horton](https://discourse.peacefulscience.org/u/Timothy_Horton)\
**Post date:** [September 13, 2020, 5:29am UTC](https://discourse.peacefulscience.org/t/cmi-and-whale-leg-genes/11676/15 "2020-09-13T05:29:47Z")

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> [@scd](#):
>
> we can say the same about design, so there is no real difference.

You can say it all you want but it won’t be true. Evolution has the evidence. We win.

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**Author:** ![Krauze](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/krauze/32/4737_2.png) [@Krauze](https://discourse.peacefulscience.org/u/Krauze)\
**Post date:** [September 13, 2020, 8:18am UTC](https://discourse.peacefulscience.org/t/cmi-and-whale-leg-genes/11676/16 "2020-09-13T08:18:38Z")

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In what sense is Tbx4 a “leg gene” if it arose before the origin of legs?

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<div class="post-metadata">

**Author:** ![Timothy\_Horton](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/timothy_horton/32/9410_2.png) [@Timothy\_Horton](https://discourse.peacefulscience.org/u/Timothy_Horton)\
**Post date:** [September 13, 2020, 2:16pm UTC](https://discourse.peacefulscience.org/t/cmi-and-whale-leg-genes/11676/17 "2020-09-13T14:16:13Z")

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In the sense Tbx4 is the T-box gene responsible for the development of hind limbs in tetrapods.

> [TBX4 T-box transcription factor 4](https://www.ncbi.nlm.nih.gov/gene/9496)
> 
> This gene is a member of a phylogenetically conserved family of genes that share a common DNA-binding domain, the T-box. T-box genes encode transcription factors involved in the regulation of developmental processes. This gene is the human homolog of mouse Tbx4, which is closely linked to Tbx2 on mouse chromosome 11. Similarly this gene, like TBX2, maps to human chromosome 17. **Expression studies in mouse and chicken show that Tbx4 is expressed in developing hindlimb, but not in forelimb buds, suggesting a role for this gene in regulating limb development and specification of limb identity.**

Tbx4 expression is suppressed in cetaceans which is why they no longer develop hind limbs even though they still carry the functioning Tbx4 gene. It’s why we occasionally find atavistic hind limbs on whales when a mutation expresses the gene. Read the paper provided in the OP.

Do you really want to stoop to CMI’s level and argue the semantics of “limb” versus “leg”?

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<div class="post-metadata">

**Author:** ![Krauze](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/krauze/32/4737_2.png) [@Krauze](https://discourse.peacefulscience.org/u/Krauze)\
**Post date:** [September 13, 2020, 5:28pm UTC](https://discourse.peacefulscience.org/t/cmi-and-whale-leg-genes/11676/18 "2020-09-13T17:28:25Z")

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> [@Timothy\_Horton](#):
>
> In the sense Tbx4 is the T-box gene responsible for the development of hind limbs in tetrapods.

But Tbx4 didn’t arise in tetrapods. As @scd pointed out, Tbx4 also exists in zebrafish, indicating that the gene existed at least far back as the Actinopterygii/Sarcopterygii split, during which tetrapod legs did not yet exist. Do zebrafish also have a “leg gene”?

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**Author:** ![John\_Harshman](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/john_harshman/32/1121_2.png) [@John\_Harshman](https://discourse.peacefulscience.org/u/John_Harshman)\
**Post date:** [September 13, 2020, 5:37pm UTC](https://discourse.peacefulscience.org/t/cmi-and-whale-leg-genes/11676/19 "2020-09-13T17:37:22Z")

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It’s really silly to talk about “leg genes” or, as it’s commonly stated, “genes for legs”. There are genes expressed during leg development, which may also be expressed in other places or may not. When expressed they may have varying downstream effects depending on whatever other genes are developmentally downstream. That’s how transcription factors work.

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<div class="post-metadata">

**Author:** ![Krauze](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/krauze/32/4737_2.png) [@Krauze](https://discourse.peacefulscience.org/u/Krauze)\
**Post date:** [September 13, 2020, 5:38pm UTC](https://discourse.peacefulscience.org/t/cmi-and-whale-leg-genes/11676/20 "2020-09-13T17:38:43Z")

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> [@John\_Harshman](#):
>
> It’s really silly to talk about “leg genes” or, as it’s commonly stated, “genes for legs”. There are genes expressed during leg development, which may also be expressed in other places or may not.

Thank you. Exactly the point I’ve been trying to get across.

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**Author:** ![Timothy\_Horton](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/timothy_horton/32/9410_2.png) [@Timothy\_Horton](https://discourse.peacefulscience.org/u/Timothy_Horton)\
**Post date:** [September 13, 2020, 5:54pm UTC](https://discourse.peacefulscience.org/t/cmi-and-whale-leg-genes/11676/21 "2020-09-13T17:54:59Z")

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> [@Krauze](#):
>
> Thank you. Exactly the point I’ve been trying to get across.

Then you agree CMI was being very disingenuous in claiming there were no genes for limb development present in extant whale?

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