The same DNA is in all four life cycles - DNA doesn't dictate phenotypes
https://darwinthenandnow.com/archives/1645/butterfly-nightmare/
Excerpts: "Why is the evolution industry silent on butterfly metamorphosis?
The answer is simple. Identifying a natural process for metamorphosis escapes a logical or, more importantly, a scientific explanation. The same DNA is in all four life cycles; the egg, the caterpillar (larva), the cocoon (pupa), and the adult butterfly. Metamorphosis, to the theory of Evolution, is a spectacular scientific enigma."
"Genetics determines the phenotype; it was thought. Francis Frick, British molecular biologist, biophysicist, and neuroscientist, called this the gene-centric theory of evolution, the “central dogma of molecular biology.” In theory, the form of a species, the phenotype, is determined by genetics (DNA), the genotype. The butterfly, however, defies Frick’s central dogma theory. During metamorphosis, the same genetics (DNA) produces different phenotypes. The evidence is clear: DNA does not exclusively control life. Evidence from the butterfly undermines the once-popular central dogma theory of evolution, the foundation of the Modern Synthesis (20th century) theory of evolution.""This gene-phenotype butterfly nightmare, more amazingly, is ubiquitous throughout nature. As Italian geneticist, Giuseppe Sermonti, points out – “Examples of highly divergent forms possessing the same DNA are so conspicuous and so numerous that the marvel is that they have attracted so little attention.”"
Epigenetics
"The same DNA in different life-forms is called “genomic equivalence,” meaning that the control of the cell is beyond the DNA, or “epigenetic.” From a more comprehensive perspective, Brian Goodwin, a Canadian developmental biologist and principal founder of theoretical biology, argues –
“While genes are responsible for determining which molecules an organism can produce, the molecular composition of organisms does not, in general, determine their form.”"
About the mechanisms
"Epigenetics can explain the phenotypic diversity of insect larvae, pupae, and adults sharing a common genome because such mechanisms globally modulate gene expression rather than altering the DNA sequence (Belles, 2017; Glastad et al., 2019).
There are three major epigenetic mechanisms, one of which is the expression of microRNAs. These short, non-coding RNAs (18–24 bp) operate at the post-transcriptional level to inhibit the translation of specific mRNAs by base-pairing with the untranslated regions or occasionally the coding region (Asgari, 2013; Hussain and Asgari, 2014). Individual microRNAs can regulate the expression of single genes or hundreds of genes. The role of microRNAs in the regulation of complete metamorphosis in holometabolous insects is well-established (Belles, 2017; Ylla et al., 2017). The first microRNAs that are differentially expressed during lepidopteran metamorphosis have been identified in the greater wax moth Galleria mellonella (Mukherjee and Vilcinskas, 2014).
The two other principal epigenetic mechanisms regulate transcriptional initiation. The first is the acetylation and deacetylation of histones by enzymes with opposing activities, thus controlling the ability of transcription factors to access chromatin and initiate gene expression. The addition of acetyl groups to histones is mediated by histone acetyltransferases (HATs), which enhance access to DNA by loosening the chromatin, whereas the removal of acetyl groups by histone deacetylases (HDACs) has the opposite effect and therefore causes gene silencing (Marks et al., 2003). We have previously shown that histone acetylation/deacetylation modulates gene expression during the complete metamorphosis of G. mellonella (Mukherjee et al., 2012). The involvement of both histone modification and microRNAs in this process provides evidence for cross-talk between different epigenetic mechanisms (Mukherjee and Vilcinskas, 2014).
The final major epigenetic mechanism is DNA methylation (Glastad et al., 2019). The addition of a methyl group to a cytosine residue in the dinucleotide sequence CpG results in the formation of 5-methylcytosine, which retains the base-pairing specificity of the unmodified nucleoside but influences its interactions with regulatory proteins. The transfer of methyl groups to DNA is mediated by evolutionarily-conserved enzymes collectively known as DNA methyltransferases (DNMTs). These can be divided further into maintenance methyltransferases (DNMT1), which complete the symmetrical methylation marks on newly-replicated DNA by recognizing the hemimethylated sequences inherited from each parent, and de novo methyltransferases (DNMT3), which establish new methylation marks on unmethylated DNA (Bestor, 2000; Klose and Bird, 2006)."
My comment: Butterfly (insect) metamorphosis is a nightmare for gene centric evolutionary theorists and also for those who claim that DNA dictates organismal traits and charactersistics (phenotype). Butterfly metamorphosis clearly points out that DNA is just passive form of information and it does nothing without epigenetic control and regulation. Don't get lost, my friends.
