When the team deactivated the genes in zebrafish embryos, the fins that developed were “truncated.”
Stiff-finned fish boldly setting “foot” on land millions of years ago is one of the most well-known chapters in the evolutionist’s history book. But while creationists have dismissed such transitions as requiring unfounded increases in genetic information, a new study suggests a loss of genetic information may have contributed to the fish-walking transition. Could it be so?
Reporting in Nature, the team, led by the University of Ottawa’s Marie-Andree Akimenko, describes two genes that play an important role in the development of zebrafish fins. More specifically, the genes code for proteins that build fibers called actinotrichia. Later, the fibers form bony fin rays in mature fish fins. Unsurprisingly, when the team deactivated the genes in zebrafish embryos, the fins that developed were “truncated.”
The team then compared the zebrafish fin development to the maturation of mouse limbs. Akimenko explained, “When we compared fin development and limb development, the early steps are very similar. But at one point there is a divergence, and that correlates with the beginning of the expression of these genes.” The scientists therefore conclude that these genes were lost during the evolutionary transition of some fish to land-walkers.
While BBC News describes the alleged loss as a “key step” in the evolution of tetrapods, we find two major faults with the study. First, the idea that the genes were “lost” during an evolutionary transition presupposes that an evolutionary transition did, in fact, occur—it interprets the presence of the genes in zebrafish and their absence in mice to an event in evolutionary history rather than to differential design. Second, the disappearance of actinotrichia and bony rays in fish fins does not account for the complex genetic changes (leading to skeletal and muscular changes) that would allow fish-like creatures to support their full weight while moving on land. As such, the evidence for this evolutionary transition remains undiscovered and, in our opinion, nonexistent.
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