New research into the domestic cat tabby pattern does not fully explain how the pattern is created

The news media is having a field day in declaring to the world that we now know how tabby cats get their stripes. And they give thanks to the team of scientists at the Hudson-Alpha Institute for Biotechnology in Huntsville, Alabama, USA who conducted the research.

Cat embryo developing its coat pattern thanks to the Dkk4 gene
Cat embryo developing its coat pattern thanks to the Dkk4 gene. Image: the research team.
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I am sure, like me, the science journalists who have written about this in online news media have struggled with the language of the author(s) who wrote the report on the research which is titled: Developmental genetics of colour pattern establishment in cats. The lead author is Christopher B Kaelin. I will take it that he wrote the report. He would do well to remember that laypeople sometimes read these reports. His write-up is completely unintelligible to the average person and cat lover. I would like to see him rewrite the report in plain, simple English so that the world can understand his work. There’s no point reporting on this sort of science if almost nobody can understand it. Yes, I know the science is complicated but it can be explained clearly. It requires a change in mindset.

And I think I can criticise them further because when you dig around into the report you don’t see a definitive, conclusive explanation as to how tabby cats get their pattern. You see some suggestions as to how it might happen and they do say that a gene which they have labelled Dickkopf 4 (full name: Dickkopf WNT Signaling Pathway Inhibitor 4, or DKK4) is involved but they don’t spell out the actual process in clear, firm, step-by-step detail as to how that gene creates the tabby pattern.

In the summary i.e. the ‘abstract’ as they say in science reports, they state “The secreted Wnt inhibitor encoded by Dickkopf 4 plays a central role in this process, and is mutated in cats with the Ticked pattern type”. So, this gene plays a ‘central role’. They could have briefly stated in the abstract what this role specifically is. And they go on to state that their research “suggest that similar mechanisms….”. Suggesting something is not stating something. What I mean is this research is not definitive as the news media are claiming.

The Dkk4 gene mutates in domestic cats to produce different tabby patterns. When you read that section of the report, they use some pretty vague language. For example, they state that “the genetic basis of Mackerel vs. Spotting is not known”. And they also state, for example, “However, Ticked is also thought to be responsible for the so-called “servaline” pattern of spotted Savannah cats. The word “thought” indicates their lack of certainty. And why is the word ‘ticked’ capitalized?

Dkk4 research
Dkk4 research. Image: the researchers.

National Geographic article

The National Geographic article written by Hannah Seo on this research is probably the best in trying to convert that impenetrable report into plain English. What I gather from this article is that when the researchers studied the skin of cat embryos that were 25-28 days old under a microscope, they found that there were thicker and thinner areas of skin which created a kind of colour pattern that resembled the tabby pattern for that individual cat (there are a variety of tabby patterns).

The researchers were surprised to see these early signs of a tabby pattern within the embryo. They are present long before the existence of hair follicles and pigmentation in the skin. The DKK4 gene is at the heart of the formation of the tabby pattern it seems. They describe it as a “secreted molecule” which sends out signals to other cells around it. And the National Geographic author states that when “everything goes as planned, cells with DKK4 eventually become the dark markings that make tabby cat tabbies”.

I’ve not seen one article on the Internet which adequately explains this research and it needs to be explained properly. This is a failure of science in my opinion. It’s important because the tabby pattern is the original domestic cat coat. For the first few thousand years of domestication of the North African wildcat, the only coat that was seen on the backs of these cats was a tabby one – a faint spotted/mackerel is the original as it is the wildcat coat.

Gradually, over time, through domestic cat evolution, other more exotic cat coat types developed because there was no need for camouflage any more. These were due to mutations. Perhaps if these cats had been wild and not domesticated these mutations would not have lasted because they don’t aid survival.

The tabby cat coat is important, as mentioned, because it is at the heart of the domestic cat in terms of appearance so, please explain how it comes about in a way that the average cat caregiver can understand.

Link to the report (note: external links sometimes break).


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