Yes, fascinating subject. I've been reading (and writing) on this for some time-- in a larger context of genetics, adaptation, etc. Small sample of the information out there:
https://royalsocietypublishing.org/doi/abs/10.1098/rspb.1990.0052
Almost every rocky outcrop and island has a unique Mbuna fauna, with endemic colour forms and species. As many of these islands and outcrops were dry land within the last 200-300 years, the establishment of the faunas has taken place within that time.
And:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC283548/
Repeated evolution of the same phenotypic difference during independent episodes of speciation is strong evidence for selection during speciation.
--most color variation among the rapidly radiated Lake Victoria cichlids and Lake Malawi Mbuna appears highly repetitive and can be partitioned into a small number of core patterns that are similar between the lakes.
--Each of the four male nuptial and three X-linked color patterns arose or was lost repeatedly within the zebra complex and additional times between the other Mbuna.
What's interesting to me is this doesn't act like Darwinian selection, even as the paper in the original post suggests:
In each case, Darwin suggested, a bird with the physical advantage was able to survive longer and produce more offspring than run-of-the-mill birds, and the trait was passed down through the generations and amplified over millions of years. He called this process natural selection to contrast it with the artificial selection performed by an animal or plant breeder working to strengthen a pedigree or create a new hybrid.
If that’s the usual understanding of Darwinian evolution, the myriad cichlids of Lake Malawi pose a real challenge to it.
The above-- rapid adaptation and speciation, repeating patterns of species consolidation and radiation producing the same patterns-- makes more sense if we look at the process with a modern understanding of genetics, not as a blueprint accumulating copying errors, which is a dated and overly simplistic model, but as functioning more like software, which is exactly what modern genetics research is finding. In fact, some articles describe it as digital but not binary (there are 4 DNA units, or 'letters'). While academics debate the terminology or implications of this, there's a lot of literature on it and science has been moving in this direction for some years now.
In any case, this or a similar model fits what happens in Lake Malawi, while the
blueprint slowly accumulating copying errors, some of them beneficial model some of us were taught in school does not. To me, having spent some years as a software tech writer, the software analogy was evident early in my reading on the genetic research of the past 15-18 years. Of course, analogy doesn't necessarily exactly equal reality, the reality is quite complex and still being unraveled. This is a huge subject with a great deal of literature. Here are a few quick samples:
https://www.forbes.com/sites/anthon...-the-double-meaning-of-dna-code/#56245afe2e9b
DNA As An App
For so long we have considered the genetic code to be something like a book to be read, a recipe for making proteins. This new discovery makes me think that DNA is actually less like a document and more like an app. These transcription factors bind to to specific sequences of DNA right next to the genes that they regulate. So we can think of these TFs as kinds of functions that employ certain logic to turn the transcription of genetic material on and off and to regulate its speed.
https://www.sciencedaily.com/releases/2014/09/140929105358.htm --
DNA signature in Ice Storm babies
https://ds9a.nl/amazing-dna/
