Peppered moth mutation found, according to reports in Science (AAAS) News, ABC News, BBC News and ScienceDaily 1 June 2016. The peppered moth, Biston betularia, comes in two forms – one speckled and one solid black. The speckled variety is the most common, but during the industrial revolution the black form became dominant in regions where trees where moths rest during the day became blackened by soot. The change from predominately speckled forms to mostly black forms is known as “industrial melanism” and is presented in biology textbooks as a case of evolution in action.
Scientists in the UK have now found a mutation that causes the solid black colour. According to Science News “the scientists found a single genetic variation in 95% of the dark moths that was missing in every pale moth they tested”. The variation is a chunk of DNA known as a transposon has been inserted into a gene named cortex in the black moths.
This was a surprise to the scientists, as the cortex gene does not have a direct connection to pigment formation. It is a gene involved in regulating cell division. However, another study of the gene in butterflies showed that it does influence colour patterns in Heliconius butterflies. Moth and butterfly wings are covered with tiny scales, and it is these that give the wings their colour. According to geneticist Nicola Nadeau of the University of Sheffield, who was involved in the butterfly study, the different coloured scales develop at different rates, so the cortex gene “could be controlling this developmental rate difference, and that is presumably how it’s controlling the butterfly colour patterns”.
Arjen van’t Hof, who was involved in the moth study, commented: “These findings provide an opportunity to further develop peppered moth industrial melanism as a tool for teaching evolutionary biology and the genetic basis of adaptation”.
ABC, BBC, ScienceDaily, Science News
Editorial Comment: This study may provide an opportunity for teaching industrial melanism, but not evolution, because the moth has not evolved. Industrial melanism does involve all the processes that evolutionary biologists like to talk about – mutation, changed environment, natural selection, survival of the fittest, but none of these produce evolution.
This study certainly seems to have revealed that a chunk of extra DNA has altered the function of an already existing gene. Furthermore, in the moth’s natural environment, this mutation is a disadvantage, which is why the black form is rare in places where the trees are their natural colour. In non-polluted trees the black forms are more visible to moth-eating birds, and therefore they get selected for dinner, rather than selected to survive. It is only in a degenerate environment, i.e. industrial pollution, that the mutation was an advantage, and even then it did not turn the moth into another kind of creature, so no evolution was occurring.
Furthermore, a mutation with the same effect must also have occurred in places with no sooty trees in the USA, and the result was the same – changing the percentage of dark and light moths, so it actually has nothing to do with survival or evolution. See our report Peppered Moth Problems and the question: PEPPERED MOTHS changed colour to survive pollution. How do you explain it if evolution isn’t true? Answer by Diane Eager here.
Ultimately, all our observations of this moth are that it has always been the same moth, with dark and light variants, and that it continues to multiply after its kind. (Ref. Lepidoptera, pigmentation, genetics)
Evidence News vol. 16 No. 10
8 June 2016
Creation Research Australia