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Betta Genetics Research Published

The very clever, National Betta Show regular, Ms Abi Rowlands has recently published some exciting new research on Betta splendens colour genetics.

For the last few years Abi has been taking an indepth look into Marble's and how the colours and patterns work at a genetic level as part of her studies at Aberystwyth University.

Well done Abi on all your hardwork!

Here the opening abstract with a link to the paper below;

Project Title:

An Investigation into the Colour Changing Capabilities of Domesticated Betta splendens with a Proposed Link to Vitiligo.


Betta splendens are a hugely important domestic fish in the ornamental hobby. This paper focusses on one specific colour characteristic found in the species, termed the ‘marble’ trait. The trait displays two main characteristics, the ability to cause an individual fish to drastically change colour overtime, and secondly, the apparently random or untraceable inheritance patterns that the trait seems to express. The most popular hypothesis currently presented by the B. splendens keeping hobby is that the trait is caused by a transposable element transpositioning into and out of pigment related genes in the chromatophores, interrupting pigment production leading to the phenotypic effect and inheritance that is seen. However, that hypothesis is flawed in many respects and searching for a single active transposable element in an undefined area of an unannotated genome could be likened to a ‘needle in a haystack’ style scenario. This paper instead investigated the marble traits possible link with the autoimmune condition vitiligo, as it shares many similarities. The candidate gene chosen was cytotoxic T-lymphocyte antigen 4 (CTLA-4), and upon investigation, a retrotransposon was discovered to be located only 4 kb away from the genes coding region. 

The similarities between vitiligo and the marble trait seen in Betta splendens are numerous, as a result, we propose that the marble trait is a form of vitiligo, caused by the knockout/inhibition of the CTLA-4 gene by a retrotransposon. This is the first time to our knowledge that vitiligo has been seen in fish or caused by a transposable element. Further research is required into this phenomenon, as unlike the vitiligo seen in mammals and birds, Betta splendens regrow their colour.