Giraffe Genome Doesn’t Support Darwinism
When evolutionists ran divination on giraffe genes, did the visage of Darwin appear?
Darwin thought he got the best of Lamarck by using his new ‘natural selection’ hypothesis to explain the giraffe’s long neck. It’s a story all high school biology students learn: Lamarck incorrectly thought that the necks became longer as giraffes stretched for the treetops. Their offspring inherited those acquired characteristics. Student’s hear that August Weismann proved Lamarck’s theory wrong by chopping off the tails of generations of mice; this demonstrated, textbooks all teach, that animals do not inherit acquired characteristics.
Then, with pomp and triumph, Darwin’s superior theory of natural selection is introduced: giraffes are tall because chance variations enabled some to reach the treetops. These survived and the short giraffes died out. The genes of the lucky giraffes were passed on to their baby giraffes. (How the young giraffes, not yet tall enough, survived starvation is not included in the story, but Charlie Darwin is congratulated anyway as the most original thinker in the history of science.)
Incidentally, Darwin became more Lamarckian in later life due to increasing criticism of natural selection by other scientists. Later editions of the Origin sound surprisingly Lamarckian (3 June 2005).
What if both theories are wrong? Lamarck and Darwin both believed that the giraffe evolved from some pre-giraffe with a short neck. What if giraffes, instead, were always tall? That seems reasonable unless one starts with the assumption that all animals have evolved from bacteria ancestors and grew to be what they are by the Stuff Happens Law. That is still the assumption of the majority of secular scientists today. According to evolution, giraffes did not try to become tall. They were never programmed to become tall. Things just turned out that way by unguided natural processes.
Genes Enter the Dispute
Now, a new complete giraffe genome can help settle the issue. Published 17 March 2021 by Liu et al. in Science Advances (open access), it gives biologists a fresh start at connecting genes to traits for this iconic mammal.
The suite of adaptations associated with the extreme stature of the giraffe has long interested biologists and physiologists. By generating a high-quality chromosome-level giraffe genome and a comprehensive comparison with other ruminant genomes, we identified a robust catalog of giraffe-specific mutations. These are primarily related to cardiovascular, bone growth, vision, hearing, and circadian functions.
What? No genes directly accounting for long necks?
The very trait that most interests everyone is never mentioned in most summaries of the paper, including those in
- Science magazine – no mention of evolution or natural selection acting on mutations.
- Copenhagen University – only speculates about “strong selection” for circadian rhythms for sleep.
- The Scientist – only mentions blood pressure and sleep as evolutionary adaptations.
Heart and bone strength are important traits for height—a giraffe needs a powerful heart and strong bones to stand so tall—but none of the articles explain from the genome how giraffes evolved long necks. Instead, they focus their attention on one particular gene named FGFRL1. In humans and mice, this gene is associated with bone strength and with blood pressure. They tried inserting the giraffe version of this gene into mouse embryos. Guess what happened: the mice did not grow long necks. But if they had, wouldn’t that be a nice storybook that Deborah Keleman could write for the kiddies? (See 13 April 2021. But since she makes up imaginary animals anyway, that fact should not stop her from writing about Miceraffes.)
A few other interesting things were found in the genome:
- Circadian rhythm genes differ. This might account for why giraffes get by with little sleep (since getting up off the ground is a “lengthy and awkward procedure”).
- Olfactory genes are reduced. The scientists speculate that smell is not as important when an animal’s nose is up at “5m compared to ground level” but that is debatable; there is a lot to smell up there, especially the leaves giraffes want to eat.
- Eyesight gene changes might account for why giraffe vision is so sharp. The evolutionists speculate that this is an “evolutionary trade-off” for less reliance on the sense of smell. Why is natural selection unable to improve both?
- So far, the genome does not account for many of the most obvious traits of the giraffe – the long neck, long legs, fur patterns and more. The authors admit that “more research on the functional consequences of giraffe-specific genetic variants is needed.”
Getting back to FGFRL1, the scientists noticed it gives two benefits for the price of one. The mouse with the giraffe version of the gene had bones that were more compact and dense. The mice also survived a drug that raises blood pressure. Since giraffe blood pressure is 2.5 times that of humans, their version of the gene is beneficial. Imagine the damage to tissues and organs from high blood pressure when a giraffe’s heart is pumping blood 16 feet off the ground. Wasn’t it lucky for a random mutation that protects from hypertension to simultaneously improve bone density?
These findings provide insights into basic modes of evolution. The dual effects of the strongly selected FGFRL1 gene are compatible with the phenomenon that one gene can affect several different aspects of the phenotype, so called evolutionary pleiotropy. Pleiotropy is particularly relevant for explaining unusually large phenotypic changes, because such changes often require that a suite of traits are changed within a short evolutionary time. Therefore, pleiotropy could provide one solution to the riddle of how evolution could achieve the many co-dependent changes needed to form an animal as extreme as a giraffe.
If pleiotropy is the explanation for the giraffe, what a lucky mutation in FGFRL1 must have occurred! Not only did it protect the giraffe from high blood pressure, it simultaneously switched on some other genes that created denser, faster-growing bones. The giraffe needed both those traits to stand up without breaking its neck and having a heart attack. The authors conclude,
Overall, these results show that pleiotropy is a plausible mechanism for contributing to the suite of co-adaptations necessary in the evolution of the giraffe’s towering stature.
Wait a minute; pleiotropy is not a mechanism. It’s an outcome. A mutation has no way of knowing that a change in one gene will help or hurt another trait. Well, since pleiotropy sounds like a “plausible mechanism” for getting the Giraffe Suite of Traits to harmonize, why not invoke it all over the animal? Think of how fewer lucky mutations would be needed. Evolution could get more done in less time with Magic Pleiotropy. With one lucky mutation, the giraffe could win its new fur patterns, a spongy tissue that keeps the giraffe’s brain from blowing out when the giraffe stoops to drink, new blood vessels and nerves for it to gallop when it raises its head to escape a lion, a new uterus for the mother to give birth to a long-legged baby, and a dozen other specific and necessary traits that would otherwise require separate lucky mutations.
Appealing to Magic Pleiotropy gets ridiculous real fast. Think about it; if the giraffe evolved gradually, all the traits would have to stay in sync as they change. How could that happen? More likely, since chance mutations are overwhelmingly deleterious, pleiotropy would hurt the animal.
Explaining giraffes by the Stuff Happens Law is only one woe for the Darwin Party. They would also have to account for gradual lengthening of necks of sauropod dinosaurs, some of which make giraffes look like pets (15 January 2021). It’s hopeless, evolutionists; give up. Join the empirically better supported view that living things reproduce after their kind (which is often broader than species; see this CMI article about relatives Okapi and Samotherium). While horizontal variations can occur, vertical evolution is pseudoscientific because it relies on sheer dumb luck.