The Proceedings of the Eighth International Conference on Creationism (2018)

evolution’ is misleading, as it implies directionality in a process [Darwinian evolution] that is near-sighted and agnostic with regard to goal. This has spawned similarly dubious concepts, such as Dollo’s Law, asserting that evolution is intrinsically irreversible…” (p. 2). Considering the dwindling evidence for the law-like nature of Dollo’s Law, Collin and Miglietta (2008) conclude that support for this view has become untenable. The mechanisms for recovery of ancestral states are slowly being deciphered. Evidently, the developmental pathways and genetics for idled traits are often retained. Galis, et al. (2010) found that, after loss of a structure, in many cases “…the genetic and developmental architecture to develop such structures continues to be fully present…” (p.2466). Couzens et al (2016) also reviewed how reversibility may be variably widespread among organisms, and state “…it has been argued that trait reversibility may be promoted when there is reutilization of conserved developmental pathways…[and] the reutilization of regulatory pathways and constituent genes is widespread in development and ancestral states are recoverable across a diverse spectrum of metazoan structures.” (p. 568). Collin and Miglietta. (2008) also describe cases where genetic and developmental pathways of “lost” traits are reactivated. Two other aspects of these reversals make them quite remarkable. First, there are the multiple instances of repeated oscillation between loss-and-reversal which, second, happened over time spans purported to range from tens to hundreds of millions of years—which counterintuitively indicates that the genetic and developmental pathways remained undegraded for astonishingly long times (Couzens et al. 2016; Freed et al. 2016; Wiens 2011). Reversion to a prior phenotype in a populationwould not necessarily involve a back-mutation. Hubert et al. (2016) acknowledge that “reversibility of evolution is a long studied and questioned aspect of evolutionary biology. Especially in small populations, slightly deleterious mutations may accumulate and become fixed by genetic drift” (p. 1). They report on European carp bred to be scale-free (homozygotous.) A population transported in 1912 from France to Madagascar (which had no native carp populations) colonized natural waters. By the 1950s, carp had re-grown scales. This development was inexplicable, since they could cite no studies confirming a survival value of scaled over non-scaled phenotypes. Their analysis found that these fish were still homozygous to be scale-free, but that scale growth was under polygenic control and the current fish were expressing scales by accessing another genetic route. They conclude that these “visible and striking” findings are “…evidence for a rescue of the wildtype-like scale cover…[by] polygenes from standing genetic variation…[through] other routes than reversion mutation, and suggests that natural populations can host enough capacity for adaptation on the short-term to face a sudden environmental change, even if a harmful mutation was formerly fixed” (p. 6). DISCUSSION 1. Variation appears directed, not random Variation perpetuates “in the classical view…[when] species experience spontaneous genetic mutations that produce various novel traits—some helpful, some detrimental. Nature then selects for those most beneficial, passing them along to subsequent generations. It’s an elegant model.” (Whitehead 2013, p. 1) Thus, in the classical view, genetic heterozygosity generated via random mutations, or conceivably originating as a standing assemblage, becomes fractioned into subpopulations by the struggle to survive in challenging environments. In dramatic contrast, the results from our survey of the literature (summarized in the regulated changes described above and further detailed in Table 2) provide evidence of multiple controlled mechanisms that bias or direct phenotypic variation in a population toward specific, adaptive outcomes. However, it has taken several decades to discover these alternative mechanisms; recognize and collate them into non-random, directed mechanistic categories; and then to realize their contributions toward variation, diversification, and adaptation. As Charlesworth et al. (2017) discuss, researchers are just beginning to determine the relative importance with regard to diversification and adaptation of these dissimilar and distinct mechanisms compared to, or perhaps contributing to, the status quo genetic fractionation explanation which they endorse. Our survey of the literature uncovered evidence that epigenetic changes are the product of systems that have sensors to detect changed conditions, that process data within logic mechanisms, and that are observed to have rapid and targeted responses. It appears that regulated, condition-sensing epigenetic mechanisms also “prime the pump” for specific adaptive variation in offspring. For example, after Weyrich (2016) detected that paternal Wild guinea pigs and their offspring had improved long-term resilience to temperature increases, he concludes, “we demonstrated immediate and inherited paternal epigenetic response with a potential adaptation reaction that occurred in response to increased ambient temperature in a wild genetically heterogeneous mammal species, the Wild guinea pig” (p.8). That epigenetic control can be adaptive and transgenerational was corroborated by Ressler commenting on his journal-published research (see Dias and Ressler 2014): “such information transfer would be an efficient way for parents to ‘inform’ their offspring about the importance of specific environmental features that they are likely to encounter in their future environments” (Le Roux 2013). In addition, Rohner et al. (2013) deduce from their results on blind cave fish, Astyanax mexicanas , from a population of sighted river fish that “because multiple variants can be unmasked at the same time, this system provides a mechanism to create complex traits in a single step… (p.1372) [that] would have helped potentiate a rapid response to the cave environment” (p.1375). Variants that can be “unmasked” precede the environmental challenge. Unmasking of variants is under tight, internal regulation so that responses occur only after organisms detect specified changes. Also, the expression of variants occurred repeatedly, within one generation, after fish were exposed during development to either an HSP90 inhibitor or to water conductivity mimicking cave conditions. These internally, self-adjusted phenotypic outputs enable this fish’s adaptive response to migration into cave environments. Taken together, these results indicate that expression of variants is a necessary and predictable consequence of an internal logic- based algorithm altering embryonic development. Those fish with unmasked variants that successfully fit the specific cave conditions tend to become dominant in a new population. Further, we found that directed phenotypic change—enabling Guliuzza and Gaskill ◀ How organisms continuously track environmental changes ▶ 2018 ICC 165