Emory Moynagh
[Originally published as Evolutionary Novelty: A Fools Quest]
The development of evolutionary novelty is uncommon. This is due to the difficulty and complexity involved in creating new traits. However, there are at least four ways that evolutionists postulate can generate novelty. Of course, novelty alone is not enough, the trait must then be selected for and fixed in a population, but this isn’t possible until novelty exists.
Gene Duplication
One way novelty can arise is through gene duplication. Genes that are duplicated can have multiple fates, of which, neofunctionalization is the only one to produce novelty (Graur, 2016). Gene duplication has been implicated in producing much of the novelty in plants (Flagel and Wendel, 2009).
C4 photosynthesis is one postulated example of a novelty that may have arisen by gene duplication. (Monson, 2003). The problem is that no new information had been produced. This is the equivalent of having two copies of the same Sunday newspaper. What you can learn from one, you can learn from the other. Having two copies does not double the information they contain.
Gene Sequence Duplication
Another method suggested for producing novelty is internal gene duplication. This differs from gene duplication in that it does not produce a new gene. Instead, sequences within the gene are duplicated and the gene is elongated (Graur, 2016).
An example of internal gene duplication occurs in corn, where the ZmHox2a gene has internally duplicated regions that code for parts of proteins (Werr, et al, 1998.) Again the problem is that no new information has been produced. Such duplication could, potentially, produce a different protein, but it’s not enough to produce a new trait, it is simply a different reading frame working on the same existing information.
Exon-shuffling
Exon-shuffling is another method that could potentially generate evolutionary novelty. It occurs when exons cross-over from one gene to another. Exons are the parts of a gene that are read and transcribed. It has been proposed that exon-shuffling is a key element of evolution (de Souza et al, 2012).
Sometimes gene duplications can be paired with exon-shuffling to produce novel genetic expression (Rogers et al, 2017). Such a pathway could create novelty on two separate occasions for the same sequences. However, again, no new information is being formed. The existing information is simply being rearranged to be read differently.
Alternative Splicing
The final potential method for producing evolutionary novelty is alternative splicing. This takes place when multiple mRNA strands can be produced from the same strand of DNA (Graur, 2016).
Alternative splicing is tightly regulated by the genome due to its propensity to cause disease if done incorrectly but is different in various primate lineages, which is interpreted as novelty (Blekhman et al, 2010). Alternative splicing has been associated with species divergence in mice, as well as changes in their transcriptome (Harr and Turner, 2010).
The ability to splice RNA transcripts multiple ways could thus be a valuable path towards evolutionary novelty. However, this is still taking what already exists and making it read differently. This is a natural function of the DNA, not any kind of evolutionary process.
Conclusion
Despite multiple pathways, evolutionary novelty is still presumed to be rare. Each of these pathways has its difficulties. Alternative splicing has been proposed as playing a key role due to the fewness of the mutations needed (Urrutia et al, 2016). While this may generate small novelties, given that at least traits are coded for polygenetically (Kayser et al, 2011), generating new traits in this way seems difficult.
Exon-shuffling and internal gene duplication suffer from the same problem to varying degrees. They can generate novel aspects of the proteome potentially but would need to do more than that to generate novel traits. Gene duplication has been suggested as the primary producer of evolutionary novelty (Gao and Lynch, 2009). While this is probably the majority view, I am uncertain that any of these alone can be a leading producer of novelty.
Alternative splicing and exon-shuffling manipulate existing DNA. Internal gene duplication and gene duplication produce new copies of existing DNA. It seems likely that some combination of the two processes would be needed to produce novel traits, for example a combination of exon-shuffling paired with gene duplications (Rogers et al, 2017).
Given that gene duplications provide most of the raw material for the generation of novelty and have been associated with it in plants (Flagel and Wendel, 2009) and arthropod photoreceptors (Oakley et al, 2007), gene duplications seem the most likely single source for novelty. But even this is a giant stretch, given the need for reams of beneficial mutations to become set in a population, and such a situation has never been observed.
Evolutionists are on a Quixotic quest for novelty that leads to them tilting at windmills.
References
Blekhman R, Marioni JC, Gilad Y, Zumbo P, Stephens M. 2010. Sex-specific and lineage-specific alternative splicing in primates. Genome Res. 20:180-189.
de Souza SJ, Franca GS, Cancherini DV. 2012. Evolutionary history of exon shuffling. Genetica. 140:249-257.
Flagel LE, Wendel JF. 2009. Gene duplication and evolutionary novelty in plants. New Phytol. 183:557-564.
Gao X, Lynch M. 2009. Ubiquitous internal gene duplication and intron creation eukaryotes. Proc Natl Acad Sci USA. 106(49):20818-20823.
Graur, D. 2016. Molecular and genome evolution. 1st. Sunderland, (MA). Sinauer Associates, Inc. 340, 368.
Harr B, Turner LM. 2010. Genome-wide analysis of alternative splicing evolution among Mus subspecies. Mol Ecol. 19(S1):228-239.
Kayser M, Branicki W, Liu F, van Duijn K, Draus-Barini J, Pośpiech E, Walsh S, Kupiec T, Wojas-Pelc A. 2011. Model-based predictions of human hair color using DNA variants. Hum Genet. 129:443-454.
Monson RK. 2003. Gene duplication, neofunctionalization, and the evolution of c4 photosynthesis. Int J Plant Sci. 164(S3).
Oakley TH, Plachetzki DC, Rivera AS. 2007. Furcation, field-splitting, and the evolutionary origins of novelty in arthropod photoreceptors. Arthropod Struct Dev. 36(4):386-400.
Rogers RL, Shao L, Thornton KR. 2017. Tandem duplications lead to novel expression patterns through exon shuffling in Drosophila yakuba. PLoS Genet. 13(5).
Urrutia AO, Bush SJ, Chen L, Tovar-Corona JM. 2017. Alternative splicing and the evolution of phenotypic novelty. Philos Trans R Soc Lond B Biol Sci. 372(1713).
Werr, W, Kirch T, Bitter S, Kisters-Woike B. 1998. The two homeodomains of the ZmHox2a gene from maize originated as an internal gene duplication and have evolved different target site specificities. Nucleic Acids Res. 26(20):4714-4720.
