holobaramins were discovered (see Figure 13A). These include the following groups: group #1: the genus Salvelinus (chars or trouts), group #2: Salmo + Parahucho (salmon and taimens), group #3: the genus Oncorhynchus (Pacific salmon and Pacific trout), group #4: Brachymystax + Hucho (lenoks and taimens), group #5: Coregonus + Stenodus (whitefishes), group #7: the genus Thymallus (graylings). Four of the six statistically significant groups have a normalized entropy value greater than 0.9. This means that the species in these four putative baramins are in the process of transitioning from euryhalinity towards stenohalinity. 27 of the 28 species that are anadromous according to the FishBase migration annotation come from these four groups. Groups #4 and #7, with normalized entropy values less than 0.5 have no species that live in saltwater. Only one of the eight species from these two groups with migratory annotation in FishBase lives in saltwater and one is potamodromous and three are non-migratory (see Figure 13C). CONCLUSIONS The original question posed in this study was whether fish would have been able to survive different salinities during the Flood. The evidence presented here gives strong support to the idea that indeed this is possible. Even some evolutionary researchers think that euryhalinity was the ancestral state of many fish groups. According to some researchers, euryhaline species that inhabit estuaries are the most capable of invading new environments with different salinity levels (Lee and Bell 1999; Schultz and McCormick 2012). The great majority of fish before the Flood could have been euryhaline, allowing them to adapt to varying water salinity as they migrated into more specialized ecological niches. Different fish groups would then become obligatory saltwater or freshwater species after a period of adaptation, such as landlocking. Some researchers suggest that the majority of extant fish are stenohaline (Gibbons et al. 2017). In contrast, as we have seen here, 46.8% of all putative groups found in this study (22/47) are euryhaline, where a euryhaline group is defined as having at least one species from saltwater, brackish water, and freshwater (see Figure 14). This also indicates that not much time has elapsed since the Flood since most kinds are still in transition from euryhalinity to stenohalinity. If longer time had elapsed, then we would expect to see the great majority of species having adapted to either freshwater or saltwater environments. In Figure 14 we can also see that seven groups have species adapted to brackish water and freshwater, three adapted to both brackish water and saltwater, and one adapted to both freshwater and saltwater. In total, 33 out of 47 groups (70.2%) have lost the ability to adapt to one of the environments. In comparison, 22 of the 47 groups (46.8%) are ‘still’ adapted to all three water environments. This indicates that some of the species in many groups are still transitioning towards either freshwater or marine environments, whereas almost half are still undifferentiated. The species from ten groups live exclusively in freshwater, and four groups inhabit marine environments only. This means that only 29.8% of all groups have fully adapted to only one environment. Variation of freshwater and saltwater species within a group (a baramin) may also imply rapid adaptation by these species. The Flood also serves as a good explanation as to why there are freshwater species within putative baramins with a majority of saltwater species. For example, shark species such as C. leucas can live in freshwater environments, such as lakes in Nicaragua. It also explains why certain freshwater Clupea species live in Lake Tanganyika, whereas their marine counterparts have not yet diverged from them morphologically. What this may mean is that during and after the Flood, different fish kinds were able to differentiate into either freshwater or saltwater specialists. It is possible that the euryhaline ancestor of species within a kind had a more robust (diverse) genome, which allowed it to survive in environments of varying salinities. Those extant stenohaline species that occupy only freshwater and saltwater niches most likely underwent gene depletion and lost part of their genetic machinery that allowed them to survive in saltwater or freshwater environments. The holobaramins defined here are tentative and need further verification. The mtDNA is only a small fraction of the genome, and thus inferences based on sequence similarity are limited. As we have seen in the case of the three rivulid species, mtDNA substitution rates can vary. It is also worth noting that in some cases, the gene order (or gene configuration) of the mtDNA might be useful to help delineate between kinds, as we have seen in the case of Anguilliformes and Pleuronectiformes. Based on sequence similarity as well as gene order, N. erythrosoma may be classified in its own holobaramin, even into its own family. Since there was little time since the Flood for mutations to accumulate in the mtDNA, the configuration of genes in the mtDNA, mtDNA sequence similarity, the length of the mitochondrial genome, and GC% (the percent of G’s and C’s in the genome) are very similar among species within the same holobaramin. We must note here that mutations themselves are only indicative of divergence from an ancestral mtDNA state. It has been shown that a very large proportion of vertebrates have a highly similar mtDNA gene order Figure 14. The number of putative holobaramins discovered in this study that contain species that live in one or more water salinity categories. F = freshwater, B = brackish water, S = saltwater. CSERHATI Molecular baraminology of fish 2023 ICC 201
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