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Matthew Cserhati has a PhD in bioinformatics, a BSc in software development and an MA in religion. He has written several dozen creation science articles and three Creation Research Society grants. One of his major accomplishments was the assembly of the whole genome sequences of Neanderthal and Denisovan and the analysis of archaic and modern human genome sequences. His main field of creation research is molecular baraminology.
Full Paper Presentation
How did freshwater and saltwater fish survive the Flood? Is it even possible for fish to adapt rapidly between saltwater and freshwater? What kind of biological mechanism make this process possible? What is the distribution of freshwater and saltwater fish species in different fish baramins?
Erosion and volcanic activity would have made the post-Flood waters saltier than the pre-Flood waters. Species richness in freshwater is currently estimated to be 14 times greater than in saltwater (Carrete Vega and Wiens, 2012), and the approximate number of freshwater and saltwater fish is about the same: around 15,000 (Seehausen and Wagner, 2014). This is despite the habitable surface area and volume of saltwater being greater compared to freshwater by a ratio of 100:1 and 10,000:1, respectively (Dawson, 2012).
Many families of fish have both saltwater and freshwater species, and many species migrate between saltwater and freshwater, such as salmon, bass, and sturgeon. Clearly, in order for different fish baramins to survive the Flood, widespread and far-reaching ecological and genetic adaptations to changing salinity were necessary during and after the Flood. The main purpose of this paper is to review the different genetic and ecological factors that allow fish to adapt between freshwater and saltwater environments.
Landlocking is a process whereby diadromous fish (species that migrate between saltwater and freshwater environments during their lifetime) lose their capability of migrating back to the ocean and permanently end up in a landlocked lacustrine environment. Diadromous fish can be either catadromous or anadromous. Catadromous fish migrate from saltwater to spawn in freshwater, whereas anadromous fish migrate from freshwater to spawn in saltwater.
During the process of landlocking, large-scale differential expression of a large repertoire of genes may take place. Due to the disappearance of selective pressures, reduced phenotypic plasticity leads to over-adaptation to a particular niche, leaving the newly landlocked species less capable of adapting to future changes in its new environment (Hunt et al. 2011). This process is similar to how eyeless fish lose genetic information associated with sight in caves.
Evolutionists assert that landlocking is evidence of natural selection producing new species, but there are two main problems with this claim. First, landlocking happens at a much faster rate than expected according to the evolutionary timescale (Palkovacs, 2008). This leaves little chance for new genes to arise during adaptation to lacustrine environments. Rather, the expression of a wide range of already existing genes is differentially expressed. The discovery of such differentially expressed gene (DEG) repertoires is greatly facilitated by RNA-seq technology, whereby dozens, or even hundreds of genes can be identified that take part in the transition between saltwater and freshwater. These pre-existing gene repertoires constitute a divinely engineered regulatory circuitry that is activated upon long-term adaptation to a landlocked environment. These gene repertoires could have allowed for post-Flood adaptation of fish to new environments due to the receding Flood waters (Genesis 8:13–14).
Proposed areas of review
This paper would review the scientific literature to see what kind of biological factors influence the landlocking process. These could include things (among others) such as:
- Change in water salinity
- Change in size
- Changes in pathogen or predator species
- Changes in lifestyles (i.e. Circadian rhythm)
- Geographical location (i.e. mainland or island populations)
- Epigenetic factors
- Sex-based differences (i.e. disproportionate dispersal of one sex due to mating)
The function of DEGs will also be examined, such as those involved in (among others):
- Ion channels, i.e.
- cystic fibrosis transmembrane conductance regulator (CFTR)
- Na+/K+-ATPase (NKA enzyme)
- Na+/K+/2Cl– cotransporter (NKCC protein)
- Transmembrane transport
- Pathogen and immune response
- Hormonal regulation
Furthermore, concrete examples of DEG repertoires will be covered in several example species, such as salmon, carp, and others.
It is also expected that since saltwater/freshwater adaptation only affects the regulation of already existing genes, then both saltwater and freshwater species should exist in the same fish baramins. mtDNA-based baraminology analysis could be performed to verify this. There are 3,305 mtDNA genome sequences in the NCBI Organelle Genome Database. Of these, several smaller sets of species could be analyzed in a series of small studies to examine the distribution of saltwater and freshwater species.
It is expected that several different genetic regulatory mechanisms are responsible for helping fish to survive the Flood and to switch between saltwater and freshwater environments in the post-Flood world. These mechanisms may vary between different baramins. They also represent irreducibly complex systems, that were specifically designed to help various fish species adapt between freshwater and saltwater environments. The mtDNA baraminology studies could verify the simultaneous presence of both freshwater and saltwater species within the same putative baramin.
freshwater, brackish water, saltwater, adaptation, molecular baraminology, Genesis Flood, mitochondrial DNA
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"Molecular Baraminology of Marine and Freshwater Fish,"
Proceedings of the International Conference on Creationism: Vol. 9, Article 29.
Available at: https://digitalcommons.cedarville.edu/icc_proceedings/vol9/iss1/29